This research was funded by the Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences &#38; Biosciences of the U.S. Department of Energy (DOE). GEJ acknowledges support from the Linus Pauling Fellowship and the Laboratory Directed Research and Development Program at the Pacific Northwest National Laboratory (PNNL). This work was performed using EMSL, a national scientific user facility sponsored by the Department of Energy&#39;s Office of Biological and Environmental Research and located at PNNL. PNNL is operated by Battelle for the U.S. DOE.

1. Preparation of COOH-SAM Surfaces on Gold for Soft Landing of Mass-selected Ions
<ol>
	<li>Obtain flat gold substrates on silicon (Si) or mica backing materials. Alternatively, prepare gold films on Si or mica surfaces according to procedures described in the literature118,119. Note: Use surfaces that have the following specifications: 1 cm2 or circular and 5 mm in diameter, 525 &#181;m thick Si layer, 50 &#197; thick Ti adhesion layer, 1,000 &#197; Au layer.</li>
	<li>Place fresh gold-on-silicon surfaces into glass scintillation vials and immerse in pure (non-denatured) ethanol.</li>
	<li>Place scintillation vials containing gold surfaces immersed in ethanol into an ultrasonic cleaner and wash for 20 min to remove any surface debris. Note: Do not ultrasonically wash gold on mica surfaces as this will detach the gold film from the mica backing material.</li>
	<li>Remove washed gold surfaces from vials and dry with a stream of pure N2 to prevent the formation of any residual spots from the ethanol.</li>
	<li>Place the dried gold surfaces face up in an ultraviolet (UV) cleaner and irradiate for 20 min to remove surface organic matter.</li>
	<li>In glass scintillation vials, prepare 5 ml of 1 mM solutions of 16-mercaptohexadecanoic acid (COOH-SAM) in non-denatured ethanol.</li>
	<li>Add hydrochloric acid to a final concentration of 1% HCl in ethanol to ensure protonation of the carboxylic acid groups of the molecules.</li>
	<li>Place the washed, dried and UV-cleaned gold surfaces face up into the COOH-SAM solutions ensuring that the entire gold surface is fully immersed in each vial. Allow the monolayer surfaces on gold to assemble for at least 24 hr in the dark (wrap vials in foil).</li>
	<li>Remove the surfaces from the COOH-SAM solutions and place in new scintillation vials containing 5 ml of 1% HCl in ethanol. Ultrasonically wash the SAM surfaces for 5 min to remove any physisorbed molecules from the monolayer surface.</li>
	<li>Remove the washed surfaces from the vials and rinse with several 1 ml aliquots of 1% HCl in ethanol. Dry the COOH-SAM surfaces under a stream of N2.</li>
	<li>Using clean metal forceps and wearing gloves place a SAM surface onto one of three metal sample mounts that are compatible with each soft landing instrument taking care not to touch the front facing gold surface in the process. Ensure that the surface is fixed tightly in place and that there is strong electrical contact between the back side of the surface and the metal sample mount.</li>
	<li>Employing the load-lock sample introduction capabilities of the soft landing instruments (each is slightly different), ensure that the gate valve separating the sample introduction region of the instrument from the soft landing chamber is closed. Bring the sample introduction chamber up to atmospheric pressure by turning off the turbomolecular vacuum pump and ionization pressure gauge and closing the valve to the foreline mechanical vacuum pump.</li>
	<li>When the sample introduction chamber reaches atmospheric pressure open the sample door and secure the sample holder firmly to the manipulator (xyz-stage or z-translator) inside of the instrument. Close the door and open the valve to the foreline mechanical vacuum pump. When the sample introduction chamber reaches a pressure of 10-3 Torr, turn on the turbomolecular vacuum pump and ionization pressure gauge.</li>
	<li>When the sample introduction chamber reaches a pressure of 10-5 Torr, open the gate valve to the soft landing chamber. Use the magnetic manipulator or xyz-stage to position the SAM surface in line with the ion beam to begin soft landing.</li>
</ol>
2. Soft Landing of Mass-selected Ru(bpy)32+ onto COOH-SAM Surfaces
<ol>
	<li>Obtain tris(2,2&#39;-bipyridyl)dichloro-ruthenium(II) hexahydrate solid. Dissolve the red crystals in pure methanol to create stock solutions with a concentration of 10-3&#8201;M. Dilute the stock solutions by a factor of either 10 or 100 with methanol to achieve optimum electrospray ion current of mass-selected Ru(bpy)32+ m/z = 285.</li>
	<li>Load the diluted solutions into 1 ml glass syringes. Use a syringe pump to infuse the solution through a 360 &#181;m outer diameter 80 &#181;m inner diameter fused silica capillary that is biased between +2 to +3 kV to generate positive ions. Adjust the syringe pump flow rate between 20-40 &#181;l/hr to obtain optimum ion current and stability at the surface.</li>
	<li>Adjust the quadrupole mass-filter to the mass of the Ru(bpy)32+ ion m/z = 285 to prevent soft landing of species other than Ru(bpy)32+ onto the surface. Using a high-resistance electrometer connected to the substrate through a vacuum electrical feed-through, adjust the voltage settings of the ion optics and radiofrequency ion guides to maximize the ion current and stability of Ru(bpy)32+ measured at the SAM surface. Allow the experiment to run for a selected period of time to achieve the desired coverage of ions on the surface of the COOH-SAM.</li>
	<li>Increase the potential gradient in the high-pressure collision quadrupole region of the soft landing instruments to create the harsh conditions that enable gas-phase ligand stripping from the organometallic ion through collision induced dissociation. Note: Examine the schematic diagram of one of the three soft landing instruments, which is also representative of the early stages of the other two instruments, which is presented in Figure 1. The fragmentation of the Ru(bpy)32+ ion occurs in region 4. Increase the voltage applied to the back plate of the electrodynamic ion funnel to remove one bipyridine ligand from Ru(bpy)32+ m/z = 285 producing gas-phase Ru(bpy)22+ m/z = 207 in region 4 of the instrument81. Mass select the highly reactive undercoordinated fragment ion using the quadrupole mass filter in region 6 of the instrument and soft land onto COOH-SAM surfaces to examine how the extent of ligation influences the properties of supported organometallic ions.</li>
	<li>Adjust the surrounding ion optics, including the DC voltages applied to the quadrupole rods as well as the conductance limit to maximize the current of mass-selected Ru(bpy)22+ fragment ions at the surface.</li>
</ol>
3. Analysis by In Situ TOF-SIMS Before and After Exposure to Reactive Gases
<ol>
	<li>Turn off the syringe pump and high voltage to the ESI emitter. Open the gate valve that separates the two regions of the instrument during operation. Use the magnetic manipulator to move the prepared surface from the soft landing chamber to the analysis stage inside the TOF-SIMS part of the instrument.</li>
	<li>Disengage the manipulator from the sample and retract it fully from the SIMS analysis chamber. Close the gate valve between the soft landing and SIMS parts of the instrument because the TOF-SIMS operates at a much lower pressure than the soft landing region of the instrument.</li>
	<li>To conduct the TOF-SIMS experiment, load the instrument control file in the software and ensure that the Ga+ source is producing a sufficiently stable current of primary ions. Note: Employ 15 keV primary gallium ions (Ga+, 500 pA, 5 nsec pulse width, 10 kHz repetition rate) to induce desorption of soft landed material from the surfaces. Extract secondary ions ejected from the surface into the mass analyzer, which consists of three separate electrostatic sectors.</li>
	<li>Acquire x- and y-axis line profiles across the surface to determine the center of the deposited spot of ions on the substrate (typically at the center of the surface and 3 mm in diameter). Position the surface so that the Ga+ primary ion beam is incident on the center of the deposited spot of ions. Acquire a TOF-SIMS mass spectrum for 5 min.</li>
	<li>Turn off the primary Ga+ ion beam and high voltages of the TOF-SIMS. Use the magnetic manipulator to move the sample back into the soft landing part of the instrument. Make sure that the gate valve separating the two chambers is closed before proceeding further.</li>
	<li>Use a high-vacuum leak valve on the soft landing chamber to introduce a controlled flow of ultra-high purity oxygen (O2) gas from a cylinder into the instrument. Use the adjustable gate valve in front of the turbomolecular vacuum pump to throttle the pumping speed of the pump to achieve a steady-state pressure of 10-4 Torr of O2 inside the soft landing chamber.</li>
	<li>Following exposure of the surface to O2 for 30 min close the leak valve, open the gate valve over the turbomolecular vacuum pump and allow the remaining O2 to pump away. After the pressure in the chamber has decreased, open the gate valve to the SIMS part of the instrument and use the magnetic manipulator to position the surface on the analysis platform for a second round of TOF-SIMS analysis.</li>
	<li>After the second TOF-SIMS spectrum is obtained as described in sections 3.3-3.4, open the gate valve and position the surface back in the soft landing chamber for exposure to 10-4 Torr of C2H4 for 30 min. Perform a SIMS analysis again as described above.</li>
</ol>
4. Analysis by In Situ FT-ICR-SIMS During and After Soft Landing
<ol>
	<li>Prepare the SAM surfaces for experiments with the in situ FT-ICR-SIMS instrument in a manner similar to that described in section 1 but on circular substrates 5 mm in diameter. Note: Use substrates that are laser cut from a gold coated silicon wafer (5 nm chromium adhesion layer and 100 nm of polycrystalline vapor-deposited gold). Be aware that the most notable difference is that in the FT-ICR-SIMS instrument the surface is positioned inside the bore of a superconducting magnet. The presence of the magnet necessitates that the surfaces be placed at the end of a 5&#160;ft manual z-translator to enable them to be positioned safely and adjustably at the rear plate of the ICR cell.</li>
	<li>Using the load-lock interface, position a circular SAM surface at the rear trapping plate of the ICR cell located inside of the 6&#160;Tesla magnet. Note: Be aware that this instrument is a specially designed 6-Tesla FT-ICR mass spectrometer configured for studying ion-surface interactions97,120.</li>
	<li>Operate the ion soft landing portion of the FT-ICR-SIMS instrument in a manner similar to that described in section 2.</li>
	<li>Use a cesium ion source to create a continuous beam of 8 kV Cs+ primary ions to sputter the surface during and after ion soft landing.</li>
	<li>Utilize the ESI source positioned at 90&#176; toward the main instrument axis to generate ions for soft landing. Focus the ions through a 90&#176; bending quadrupole120. Note: Be aware this instrument geometry facilitates simultaneous soft landing of Ru(bpy)32+ and transmission of the primary Cs+ ion beam to the surface thereby enabling the monitoring of the soft landing process both during and after ion deposition.</li>
	<li>Trap and analyze the secondary ions ejected from the surface using FT-ICR-MS. Note: Employ static SIMS conditions corresponding to a total ion flux of about 1010 ions/cm2 (current 4 nA, duration 80 &#181;sec, spot diameter 4.6 mm, 10 shots per spectrum, ~200 data points) for these experiments that last for about 7 hr. Average each SIMS spectrum over 10 shots corresponding to an acquisition time of ~10 sec.</li>
	<li>Acquire kinetics data by sampling the SAM surface every 4 min for approximately 7 hr during and after ion deposition.</li>
	<li>Perform data acquisition and instrument control using an automated modular data control system described in the literature121.</li>
</ol>
5. Analysis by In Situ IRRAS During and After Soft Landing
<ol>
	<li>Prepare the SAM surfaces for experiments with the in situ IRRAS instrument in a manner similar to that described in section 1. Note: Be aware that the largest difference with the IRRAS instrument results from the precise positioning of the surface with the z-translator that is necessary to locate the substrate at the focal point of the parabolic mirrors and in line with the beam of ions. Maximize the overlap between the infrared beam and the spot of deposited ions on the surface.</li>
	<li>Conduct the IRRAS experiments in a grazing-incidence geometry employing an FTIR spectrometer equipped with a liquid nitrogen cooled mercury-cadmium-telluride (MCT) detector.</li>
	<li>Utilize a gold-coated flat mirror to direct the light exiting the FTIR spectrometer onto a parabolic gold mirror. Reflect the light from the parabolic mirror through a mid-infrared wire grid polarizer and into the vacuum chamber through a viewport.</li>
	<li>Direct the infrared light from the spectrometer onto the COOH-SAM surface positioned inside the vacuum chamber. Note: The vacuum chamber is held at a pressure of 10-5 Torr during ion soft landing.</li>
	<li>Position the reflective SAM on gold surface inside the vacuum chamber at the focal point of the first parabolic mirror using the motor-driven z-translator.</li>
	<li>Reflect the IR light entering the vacuum chamber from the surface of the SAM and out of the chamber through a second viewport. Use a second parabolic gold mirror to focus the reflected light from the surface onto an MCT detector.</li>
	<li>Purge the pathway of the IR beam outside of the vacuum chamber with N2.</li>
	<li>Acquire spectra at set intervals during the deposition.</li>
</ol>

The authors have nothing to disclose.

Soft landing of mass-selected ions is generally conducted employing unique custom-built instrumentation that exists in several laboratories around the world that are specially equipped for these experiments. Modifications are constantly being made to these instruments to facilitate the ionization of a wider array of compounds, to achieve larger ion currents and shorter deposition times, to multiplex soft landing and thereby achieve simultaneous deposition of several species at different locations on the surface, and to a...

Soft landing of mass-selected ions onto surfaces remains a subject of current research interest due to the demonstrated capabilities of the technique for the highly-controlled preparation of novel materials1-6. Recent efforts have indicated potential future applications of soft landing of mass-selected ions in the preparation of peptide and protein arrays for use in high-throughput biological screening7,8, separation of proteins and conformational enrichment of peptides9-12, covalent attachment of peptides to surfaces9,10,13,14, chiral enrichment of organic compounds15, electrochemical characterization of specific redox-active proteins16-18, production of thin molecular films19,20, processing of macromolecules such as graphene21 and preparation of model catalyst systems through soft landing of ionic clusters22-39, nanoparticles40-48 and organometallic complexes onto support materials19,49-56. The concept of modifying surfaces through soft landing of polyatomic ions was initially proposed by Cooks and co-workers in 197757. In the subsequent years a wide range of instrumental approaches have been developed for the controlled deposition of mass-selected ions from the gas-phase onto surfaces1,4,5. Ions have been produced through processes such as electrospray ionization (ESI)10,58,59, matrix- assisted laser desorption/ionization (MALDI)21, electron impact ionization (EI)60,61, pulsed arc discharge62, inert gas condensation36,63, magnetron sputtering64,65, and laser vaporization25,66,67. Mass selection of gas-phase ions prior to soft landing has been achieved principally employing quadrupole mass filters58,68,69, magnetic deflection devices70, and linear ion trap instruments8,59. A particularly notable advance in ion soft landing methodology occurred recently with the successful implementation of ambient ion soft- and reactive landing by Cooks and co-workers71,72. Using these various ionization and mass-selection techniques, the interactions of hyperthermal (&#60;100 eV) polyatomic ions with surfaces have been studied in order to better understand the factors influencing the efficiency of ion soft landing and the competing processes of reactive and unreactive scattering as well as surface induced dissociation4,73-75.
The preparation of well-defined model catalysts for research purposes has been a particularly fruitful application of soft landing of mass-selected ions25,34,35,56,76-81. In the size range of nanoscale clusters, where physical and chemical behavior does not scale linearly with cluster size, it has been demonstrated that the addition or removal of single atoms to or from clusters may drastically influence their chemical reactivity82-84. This nanoscale phenomenon, which results from quantum confinement, was demonstrated convincingly by Heiz and co-workers85 for a model catalyst consisting of soft landed clusters of eight gold atoms (Au8) supported on a defect-rich MgO surface. Several additional studies have provided evidence of the size-dependent reactivity of clusters supported on surfaces34,77,86,87. Moreover, high resolution electron microscopy images indicate that clusters containing as few as ten88 and fifty five89 atoms may be largely responsible for the superior activity of bulk-synthesized gold catalysts supported on iron oxides. Employing soft landing of mass-selected ions, it is possible to prepare stable arrays of size-selected clusters and nanoparticles that do not diffuse and agglomerate into larger structures on the surface of support materials90-92. These previous studies indicate that with continuing development, soft landing of mass-selected clusters and nanoparticles may become a versatile technique for the creation of highly active heterogeneous catalysts that exploit the emergent behavior of large numbers of identical clusters and nanoparticles in extended arrays on surfaces. These extremely well-defined systems may be used for research purposes to understand how critical parameters such as cluster size, morphology, elemental composition and surface coverage influence catalytic activity, selectivity and durability.
Organometallic complexes that are typically used in the solution-phase as homogeneous catalysts also may be immobilized on surfaces through soft landing of mass-selected ions56,80,81. Attaching ionic metal-ligand complexes to solid supports to produce hybrid organic-inorganic materials is currently an active area of research in the catalysis and surface science communities93. The overall goal is to obtain the high selectivity toward a desired product of solution-phase metal-ligand complexes while facilitating an easier separation of products from catalysts and reactants remaining in solution. In this manner, surface immobilized organometallic complexes reap the benefits of both homogeneous and heterogeneous catalysts. Through selection of an appropriate substrate it is possible to maintain or even enhance the organic ligand environment around the active metal center while also achieving strong surface immobilization94.&#160;Self-assembled monolayer surfaces (SAMs) on gold may be terminated with a number of different functional groups and are, therefore, ideal systems to investigate the feasibility of tethering organometallic complexes to surfaces through soft landing of mass-selected ions95. Furthermore, ionization methods such as atmospheric pressure thermal desorption ionization (APTDI) have been demonstrated previously to yield gas-phase mixed-metal inorganic complexes that are not accessible through synthesis in solution96. In a similar vein, non-thermal kinetically-limited synthesis and ionization techniques such as magnetron sputtering65, gas aggregation63 and laser vaporization66 also may be coupled with ion soft landing instrumentation to provide a versatile route to novel inorganic clusters and nanoparticles supported on surfaces.
In order to evolve soft landing of mass-selected ions into a mature technology for the preparation of materials, it is critical that informative analytical methods be coupled with soft landing instrumentation to probe the chemical and physical properties of surfaces before, during and after deposition of ions. To date, a multitude of techniques have been applied for this purpose including secondary ion mass spectrometry (SIMS)19,97-100, temperature programmed desorption and reaction50,52, laser desorption and ionization101, pulsed molecular beam reaction102, infrared spectroscopy (FTIR and Raman)98,103,104, surface enhanced Raman spectroscopy103,105, cavity ringdown spectroscopy106, x-ray photoelectron spectroscopy35,107, scanning tunneling microscopy33,108-111, atomic force microscopy112-114, and transmission electron microscopy39. However, to most accurately characterize surfaces prepared or modified by ion soft landing, it is crucial that the analysis be performed in situ without exposure of the substrate to the environment in the laboratory. Previous analyses conducted in situ have provided insight into phenomena such as the reduction of ionic charge of soft landed ions over time37,38,115,116, the desorption of soft landed ions from surfaces52, the efficiency and kinetic energy dependence of ion reactive landing14,81, and the influence of size on the catalytic activity of clusters and nanoparticles deposited onto surfaces117. By way of example, in our laboratory, we have systematically studied the charge reduction kinetics of protonated peptides on the surfaces of different SAMs3. These experiments were performed with a unique soft landing instrument coupled to a Fourier transform ion cyclotron resonance secondary ion mass spectrometer (FT-ICR-SIMS) that enables in situ analysis of surfaces both during and after soft landing of ions97. To expand upon these analytical capabilities, another instrument was constructed that allows in situ characterization of soft landed ions on surfaces using IRRAS104. This surface-sensitive infrared technique enables bond formation and destruction processes as well as conformational changes in complex ions and surface layers to be monitored in real time both during and after soft landing12. For instance, using IRRAS it was demonstrated that ion soft landing may be used to covalently immobilize mass-selected peptides on N-hydroxysuccinimidyl ester functionalized SAMs13,14.
Herein, we illustrate the capabilities of three unique custom-built instruments located at the Pacific Northwest National Laboratory that are designed for in situ TOF-SIMS, FT-ICR-SIMS, and IRRAS analysis of substrates produced through soft landing of mass-selected ions onto surfaces. As a representative system, we present results for soft landing of mass-selected organometallic ruthenium tris(bipyridine) dications [Ru(bpy)3]2+ onto carboxylic acid terminated SAMs (COOH-SAMs) to prepare immobilized organometallic complexes. It is shown that in situ TOF-SIMS offers the advantages of extremely high sensitivity and large overall dynamic range which facilitates identification of low abundance species including reactive intermediates that may only be present for short periods of time on the surfaces. TOF-SIMS also provides insight into how the removal of a ligand from an organometallic ion in the gas-phase, prior to soft landing, influences its efficiency toward immobilization on surfaces and its chemical reactivity towards gaseous molecules. Complementary characterization using in situ FT-ICR-SIMS provides insights into the charge reduction, neutralization and desorption kinetics of the doubly charged ions on the surface while in situ IRRAS probes the structure of the organic ligands surrounding the charged metal centers, which may influence the electronic properties and reactivity of the immobilized ions. Collectively, we illustrate how soft landing of mass-selected ions combined with in situ analysis by SIMS and IRRAS provides insight into the interactions between well-defined species and surfaces which have implications for a broad range of scientific endeavors.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Gold on Silicon Substrates 1 cm2</td>
			<td style="width:187px;">Platypus Technologies</td>
			<td style="width:209px;">Au.1000.SL1custom</td>
			<td style="width:287px;"> </td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:347px;">Gold on Silicon Substrates 4.8 mm diameter circular</td>
			<td style="width:187px;">SPI Supplies</td>
			<td>4176GSW-AB</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Glass Scintillation Vials</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:209px;">03-337-14</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Non-denatured Ethanol</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:209px;">459836-1L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Ultraviolet Cleaner</td>
			<td style="width:187px;">Boekel Scientific </td>
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			<td height="21" style="height:21px;width:347px;">16-Mercaptohexadecanoic Acid</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:209px;">448303-5G</td>
			<td></td>
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			<td height="21" style="height:21px;width:347px;">Hydrochloric Acid</td>
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			<td style="width:209px;">320331-500ML</td>
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			<td height="21" style="height:21px;width:347px;">Aluminum Foil</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:209px;">Z185140-1EA</td>
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			<td height="21" style="height:21px;width:347px;">Metal Forceps/Tweezers</td>
			<td style="width:187px;">Wiha</td>
			<td style="width:209px;">49185</td>
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			<td height="21" style="height:21px;width:347px;">Nitrile Gloves</td>
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		<tr height="42">
			<td height="42" style="height:42px;width:347px;">Tris(2,2&#8242;-bipyridine)dichlororuthenium(II) hexahydrate</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:209px;">224758-1G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Methanol</td>
			<td style="width:187px;">Sigma-Aldrich</td>
			<td style="width:209px;">322415-1L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">1 mL Gas Tight Glass Syringe</td>
			<td style="width:187px;">Hamilton</td>
			<td style="width:209px;"> </td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Syringe Pump</td>
			<td style="width:187px;">KD Scientific</td>
			<td style="width:209px;">100</td>
			<td></td>
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			<td height="21" style="height:21px;width:347px;">360 um ID Fused Silica Capillary</td>
			<td style="width:187px;">Polymicro Technologies</td>
			<td style="width:209px;">TSP075375</td>
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			<td height="21" style="height:21px;width:347px;">High Resistance Electrometer</td>
			<td style="width:187px;">Keithley</td>
			<td style="width:209px;">6517A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Commercial TOF-SIMS Instrument</td>
			<td style="width:187px;">Physical Electronics</td>
			<td style="width:209px;">TRIFT </td>
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		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Ultra High Purity Oxygen</td>
			<td style="width:187px;">Matheson</td>
			<td style="width:209px;">G1979175</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Research Purity Ethylene</td>
			<td style="width:187px;">Matheson</td>
			<td style="width:209px;">G2250178</td>
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			<td height="21" style="height:21px;width:347px;">Cesium Ion Source</td>
			<td style="width:187px;">Heat Wave Labs</td>
			<td style="width:209px;">101502</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:347px;">Commercial FTIR Spectrometer</td>
			<td style="width:187px;">Bruker</td>
			<td style="width:209px;">Vertex 70</td>
			<td></td>
		</tr>
	</tbody>
</table>

in situ sims and ir spectroscopy of well-defined surfaces prepared by soft landing of mass-selected ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)3]2+ (bpy = bipyridine), onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.

1. Investigating the Reactivity of Ru(bpy)32+ on COOH-SAMs Using In Situ TOF-SIMS
Soft landing of mass-selected organometallic ions onto functionalized SAMs is first illustrated using in situ TOF-SIMS to provide maximum sensitivity toward detection of adducts formed between the deposited ions and the individual molecules in the monolayers as well as any products of chemical reactions following exposure of the surfaces to reactive gases. The doubly charged ...

Watch this Scientific Journal Video about In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions at JoVE.com

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of novel materials. Coupled with analysis by in situ secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS), soft landing provides unprecedented insights into the interactions of well-defined species with surfaces.

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using ...

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Chemistry

18.0K Views.  Pacific Northwest National Laboratory. Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of novel materials. Coupled with analysis by in situ secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS), soft landing provides unprecedented insights into the interactions of well-defined species with surfaces.

Video: In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Dynamic Electrochemical Measurement of Chloride Ions

This protocol describes the dynamic measurement of chloride ions using the transition time of a silver silver chloride (Ag/AgCl) electrode. Silver silver chloride electrode is used extensively for potentiometric measurement of chloride ions concentration in electrolyte. In this measurement, long-term and continuous monitoring is limited due to the inherent drift and the requirement of a stable reference electrode. We utilized the chronopotentiometric approach to minimize drift and avoid the use of a conventional reference electrode. A galvanostatic pulse is applied to an Ag/AgCl electrode which initiates a faradic reaction depleting the Cl&#713; ions near the electrode surface. The transition time, which is the time to completely deplete the ions near the electrode surface, is a function of the ion concentration, given by the Nernst equation. The square root of the transition time is in linear relation to the chloride ion concentration. Drift of the response over two weeks is negligible (59 &#181;M/day) when measuring 1 mM [Cl&#713;]using a current pulse of 10 Am-2. This is a dynamic measurement where the moment of transition time determines the response and thus is independent of the absolute potential. Any metal wire can be used as a pseudo-reference electrode, making this approach feasible for long-term measurement inside concrete structures.

Dynamic measurement of chloride ions is presented. Transition time of an Ag/AgCl electrode, during a chronopotentiometric technique, can give the concentration of chloride ions in electrolyte. This method does not require a stable conventional reference electrode.

This protocol describes the dynamic measurement of chloride ions using the transition time of a silver silver chloride (Ag/AgCl) electrode. Silver silver ...

In Situ Characterization of Hydrated Proteins in Water by SALVI and ToF-SIMS

This work demonstrates in situ characterization of protein biomolecules in the aqueous solution using the System for Analysis at the Liquid Vacuum Interface (SALVI) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The fibronectin protein film was immobilized on the silicon nitride (SiN) membrane that forms the SALVI detection area. During ToF-SIMS analysis, three modes of analysis were conducted including high spatial resolution mass spectrometry, two-dimensional (2D) imaging, and depth profiling. Mass spectra were acquired in both positive and negative modes. Deionized water was also analyzed as a reference sample. Our results show that the fibronectin film in water has more distinct and stronger water cluster peaks compared to water alone. Characteristic peaks of amino acid fragments are also observable in the hydrated protein ToF-SIMS spectra. These results illustrate that protein molecule adsorption on a surface can be studied dynamically using SALVI and ToF-SIMS in the liquid environment for the first time.

In Situ Characterization of Hydrated Proteins in Water by SALVI and ToF-SIMS

This work presents a protocol for liquid handling and sample introduction to a microchannel for in situ time-of-flight secondary ion mass spectrometry analysis of protein biomolecules in an aqueous solution.

This work demonstrates in situ characterization of protein biomolecules in the aqueous solution using the System for Analysis at the Liquid Vacuum ...

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153&#176;) but a lower sliding angle (16&#176;) than F-SCHGM, with a contact angle of 141.2&#176; and a sliding angle of 67&#176;. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m&#183;K), was quite like the original HGM, which was 0.0475 W/(m&#183;K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m&#183;K) and 0.0543 W/(m&#183;K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method

This manuscript proposes a soft-chemistry method to synthesize superhydrophobic, TiO2-coated hollow glass microspheres (HGM) with high IR-reflective properties.

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 ...

In Situ Characterization of Shewanella oneidensis MR1 Biofilms by SALVI and ToF-SIMS

Bacterial biofilms are surface-associated communities that are vastly studied to understand their self-produced extracellular polymeric substances (EPS) and their roles in environmental microbiology. This study outlines a method to cultivate biofilm attachment to the System for Analysis at the Liquid Vacuum Interface (SALVI) and achieve in situ chemical mapping of a living biofilm by time-of-flight secondary ion mass spectrometry (ToF-SIMS). This is done through the culturing of bacteria both outside and within the SALVI channel with our specialized setup, as well as through optical imaging techniques to detect the biofilm presence and thickness before ToF-SIMS analysis. Our results show the characteristic peaks of the Shewanella biofilm in its natural hydrated state, highlighting upon its localized water cluster environment, as well as EPS fragments, which are drastically different from the same biofilm's dehydrated state. These results demonstrate the breakthrough capability of SALVI that allows for in situ biofilm imaging with a vacuum-based chemical imaging instrument.

In Situ Characterization of Shewanella oneidensis MR1 Biofilms by SALVI and ToF-SIMS

This article presents a method for growing a biofilm for in situ time-of-flight secondary ion mass spectrometry for chemical mapping in its hydrated state, enabled by a microfluidic reactor, System for Analysis at the liquid Vacuum Interface. The Shewanella oneidensis MR-1 with green fluorescence protein was used as a model.

Bacterial biofilms are surface-associated communities that are vastly studied to understand their self-produced extracellular polymeric substances (EPS) ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity and convenient colorimetric readout. However, high densities of nanoparticles are typically needed for detection. The available synthesis-based enhancement protocols are either limited to gold and silver nanoparticles or rely on precise enzymatic control and optimization. Here, we present a protocol to enhance the colorimetric readout of gold, silver, silica, and iron oxide nanoprobes. It was observed that the colorimetric signal can be improved by up to a 10000-fold factor. The basis for such signal enhancement strategies is the chemical reduction of Au3+ to Au0. There are several chemical reactions that enable the reduction of Au3+ to Au0. In the protocol, Good&#39;s buffers and H2O2 are used and it is possible to favor the deposition of Au0 onto the surface of existing nanoprobes, in detriment of the formation of new gold nanoparticles. The protocol consists of the incubation of the microarray with a solution consisting of chloroauric acid and H2O2 in 2-(N-morpholino)ethanesulfonic acid pH 6 buffer following the nanoprobe-based detection assay. The enhancement solution can be applied to paper and glass-based sensors. Moreover, it can be used in commercially available immunoassays as demonstrated by the application of the method to a commercial allergen microarray. The signal development requires less than 5 min of incubation with the enhancement solution and the readout can be assessed by naked eye or low-end image acquisition devices such as a table-top scanner or a digital camera.

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

In this work, a protocol for signal enhancement of nanoprobe-based biosensing is presented. The protocol is based on the reduction of chloroauric acid onto the surface of existing nanoprobes that consist of gold, silver, silica or iron-oxide nanoparticles.

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity ...

In Situ Lithiated Reference Electrode: Four Electrode Design for In-operando Impedance Spectroscopy

Extending operating voltage of Li-ion batteries results in higher energy output from these devices. High voltages, however, may trigger or accelerate multiple processes responsible for long-term performance decay. Given the complexity of physical processes occurring inside the cell, it is often challenging to achieve a full understanding of the root causes of this performance degradation. This difficulty arises in part from the fact that any electrochemical measurement of a battery will return the combined contributions of all components in the cell. Incorporation of a reference electrode can solve part of the problem, as it allows the electrochemical reactions of the cathode and the anode to be individually probed. A variation in the voltage range experienced by the cathode, for example, can indicate alterations in the pool of cyclable lithium ions in the full-cell. The structural evolution of the many interphases existing in the battery can also be monitored, by measuring the contributions of each electrode to the overall cell impedance. Such wealth of information amplifies the reach of diagnostic analysis in Li-ion batteries and provides valuable input to the optimization of individual cell components. In this work, we introduce the design of a test cell able to accommodate multiple reference electrodes, and present reference electrodes that are appropriate for each specific type of measurement, detailing the assembly process in order to maximize the accuracy of the experimental results.

The incorporation of reference electrodes in a Li-ion battery provides valuable information to elucidate degradation mechanisms at high voltages. In this article, we present a cell design that accommodates multiple reference electrodes, along with the assembly steps to assure maximum accuracy of the data obtained in electrochemical measurements.

Extending operating voltage of Li-ion batteries results in higher energy output from these devices. High voltages, however, may trigger or accelerate ...

Elemental-sensitive Detection of the Chemistry in Batteries through Soft X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid based on volatile solar and wind sources. The pressing demand of developing high-performance electrochemical energy storage solutions, i.e., batteries, relies on both fundamental understanding and practical developments from both the academy and industry. The formidable challenge of developing successful battery technology stems from the different requirements for different energy-storage applications. Energy density, power, stability, safety, and cost parameters all have to be balanced in batteries to meet the requirements of different applications. Therefore, multiple battery technologies based on different materials and mechanisms need to be developed and optimized. Incisive tools that could directly probe the chemical reactions in various battery materials are becoming critical to advance the field beyond its conventional trial-and-error approach. Here, we present detailed protocols for soft X-ray absorption spectroscopy (sXAS), soft X-ray emission spectroscopy (sXES), and resonant inelastic X-ray scattering (RIXS) experiments, which are inherently elemental-sensitive probes of the transition-metal 3d and anion 2p states in battery compounds. We provide the details on the experimental techniques and demonstrations revealing the key chemical states in battery materials through these soft X-ray spectroscopy techniques.

Here, we present a protocol for typical experiments of soft X-ray absorption spectroscopy (sXAS) and resonant inelastic X-ray scattering (RIXS) with applications in battery material studies.

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid ...

Accumulation and Analysis of Cuprous Ions in a Copper Sulfate Plating Solution

Knowledge of the behavior of cuprous ions (monovalent copper ion: Cu(I)) in a copper sulfate plating bath is important for improving the plating process. We successfully developed a method to quantitatively and easily measure Cu(I) in a plating solution and used it for evaluation of the solution. In this paper, a quantitative absorption spectrum measurement and a time-resolved injection measurement of Cu(I) concentrations by a color reaction are described. This procedure is effective as a method to reproduce and elucidate the phenomenon occurring in the plating bath in the laboratory. First, the formation and accumulation process of Cu(I) in solution by electrolysis of a plating solution is shown. The amount of Cu(I) in the solution is increased by electrolysis at higher current values &#8203;&#8203;than the usual plating process. For the determination of Cu(I), BCS (bathocuproinedisulfonic acid, disodium salt), a reagent that selectively reacts with Cu(I), is used. The concentration of Cu(I) can be calculated from the absorbance of the Cu(I)-BCS complex. Next, the time measurement of the color reaction is described. The color reaction curve of Cu(I) and BCS measured by the injection method can be decomposed into an instantaneous component and a delay component. By analysis of these components, the holding structure of Cu(I) can be clarified, and this information is important when predicting the quality of the plating film to be produced. This method is used to facilitate the evaluation of the plating bath in the production line.

Here, accumulation of cuprous ions in a copper sulfate plating solution in a model experiment and an analysis based on quantitative measurements are described. This experiment reproduces the accumulation process of cuprous ions in the plating bath.

Knowledge of the behavior of cuprous ions (monovalent copper ion: Cu(I)) in a copper sulfate plating bath is important for improving the plating process. ...

Analysis of Complex Molecules and Their Reactions on Surfaces by Means of Cluster-Induced Desorption/Ionization Mass Spectrometry

Desorption/Ionization Induced by Neutral SO2 Clusters (DINeC) is employed as a very soft and efficient desorption/ionization technique for mass spectrometry (MS) of complex molecules and their reactions on surfaces. DINeC is based on a beam of SO2 clusters impacting on the sample surface at low cluster energy. During cluster-surface impact, some of the surface molecules are desorbed and ionized via dissolvation in the impacting cluster; as a result of this dissolvation-mediated desorption mechanism, low cluster energy is sufficient and the desorption process is extremely soft. Both surface adsorbates and molecules of which the surface is composed of can be analyzed. Clear and fragmentation-free spectra from complex molecules such as peptides and proteins are obtained. DINeC does not require any special sample preparation, in particular no matrix has to be applied. The method yields quantitative information on the composition of the samples; molecules at a surface coverage as low as 0.1 % of a monolayer can be detected. Surface reactions such as H/D exchange or thermal decomposition can be observed in real-time and the kinetics of the reactions can be deduced. Using a pulsed nozzle for cluster beam generation, DINeC can be efficiently combined with ion trap mass spectrometry. The matrix-free and soft nature of the DINeC process in combination with the MSn capabilities of the ion trap allows for very detailed and unambiguous analysis of the chemical composition of complex organic samples and organic adsorbates on surfaces.

Neutral SO2 clusters of low kinetic energy (&#60; 0.8 eV/constituent) are used to desorb complex surface molecules such as peptides or lipids for further analysis by means of mass spectrometry using an ion trap mass spectrometer. No special sample preparation is required, and real-time observation of reactions is possible.