Name: probing the structure and dynamics of interfacial water with scanning tunneling microscopy and spectroscopy
Uploaded: 2018-05-27T13:00:00
Description: Watch this Scientific Journal Video about Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy at JoVE.com

Dette arbejde er finansieret af den nationale nøgle R & D Program under Grant No. 2016YFA0300901 2016YFA0300903 og 2017YFA0205003, National Natural Science Foundation of China under Grant No. 11634001, 11290162/A040106. Y.J. anerkender støtte fra National Science Fond for fremtrædende unge akademikere og Cheung Kong Young Scholars Program. J. G. anerkender støtte fra de nationale postdoc Program for Innovative talenter.

Bemærk: Eksperimenter er udført på vandmolekyler adsorberet på Au-støttede NaCl(001) film (figur 1en) på 5 K med en ultrahigh-vakuum (UHV) kryogene STM udstyret med Nanonis elektronisk controller.
1. fabrikation af eksperimentel prøve
<ol><li>
Ren Au(111) enkelt krystal
	<ol>
<li>Pumpe gas linje til presset af ~ 10-7 mbar og derefter skylle gas linje med Ar gas. Sætte gennem pumpe/flush cyklus for tre gange.<b...

<ol>
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For at undersøge den indre struktur, dynamik og vibrationelle spektroskopi af vandmolekyler adsorberet til de faste overflader, med særlig vægt på frihedsgrader af hydrogen, er nogle eksperimentelle trin af afgørende betydning, som vil blive drøftet i de følgende afsnit.
Den orbital billeddannelse af vandmolekyler er opnået, baseret på to vigtige skridt. Først, de isolerende NaCl film afkoble vand elektronisk fra Au substrat, andet orbital gating effekt af STM-tip via tip-vand koblin...

Vekselvirkninger mellem vand og overflader af faste stoffer er involveret i forskellige overflade reaktion processer, såsom Heterogen katalyse, photoconversion, elektrokemi, korrosion og smøring et al. 1 , 2 , 3 generelt for at undersøge interfacial vand, spektroskopiske og diffraktion teknikker er almindeligt anvendt, såsom infrarød og Raman spektroskopi, sum-frekvens generation (SFG), røntgen diffraktion (XRD), Kernemagnetisk resonans (NMR), neutron spredning4,5,6,7,8. Men disse metoder lider af begrænsning af rumlige opløsning, spektrale udvidelse og gennemsnit effekter.
STM er en lovende teknik til at overvinde disse begrænsninger, som kombinerer den sub-Ångström rumlige opløsning, atomic manipulation, og single-bond vibrationelle følsomhed9,10,11,12 , 13 , 14. siden begyndelsen af dette århundrede, STM er blevet flittigt anvendt til at undersøge strukturen og dynamikken i vand på faste overflader3,15,16,17, 18,19,20. Derudover vibrationelle spektroskopi baseret på STM kunne indhentes fra anden-afledte differential tunneling ledningsevne (d2jeg / dV2), også kendt som uelastisk elektron tunneling spektroskopi (IETS). Løse den interne struktur, dvs. H-bond direktionalitet, og erhverve pålidelige vibrationelle spektroskopi af vand er dog stadig udfordrende. Den største vanskelighed ligger i, at vand er en tæt shell molekyle, hvis grænse orbitaler er langt væk fra EF, således elektroner fra STM-tip kan næppe tunnel i molekylær resonans stater af vand, hvilket fører til dårlig signal / støj-forhold molekylær billeddannelse og vibrationelle spektroskopi.
Vand adsorberet på Au-støttede NaCl(001) film giver et ideelt system for atomic-scale undersøgelse af STM med Cl-afsluttet spids (figur 1en), som er udført på 5 K i ultrahigh-vakuum (UHV) miljø med en base pres bedre end 8 × 10-11 mbar. På den ene side afkoble de isolerende NaCl film vandmolekyler elektronisk fra Au substrat så native grænse-orbitaler vand bevares og levetid af elektronerne bosat i den molekylære resonant stat er forlænget. På den anden side kunne STM-tip effektivt tune den grænse orbital vand mod EF via tip-vand kobling, især når spidsen er functionalized med en Cl atom. Disse vigtige trin aktiverer høj opløsning orbital imaging og vibrationelle spektroskopi af vand monomerer og klynger. Derudover kunne vandmolekyler manipuleres i et godt kontrolleret måde, på grund af den stærke elektrostatiske interaktion mellem de negativt ladede Cl-tip og vand.
I denne betænkning, er forberedelse procedurer af prøven og Cl-afsluttet spidsen for STM undersøgelse beskrevet i detaljer i afsnit 1 og 2, henholdsvis. I afsnit 3 beskriver vi orbital imaging teknik, som O-H retning for indtastning af vand monomere og tetramer er løst. Tip-forstærket IETS er indført i afsnit 4, som giver mulighed for påvisning af vibrationelle tilstande af vandmolekyler på single-bond grænse og bestemmelse af H-bonding styrken med høj nøjagtighed fra red shift i ilt-brint stretching hyppigheden af vand. I afsnit 5 viser vi hvordan vand tetramer kan være konstrueret og skiftet af kontrollerede tip manipulation. Baseret om orbital billeddannelse og spektroskopi og manipulation teknikker, kan isotopisk substitution eksperimenter udføres for at sonde kvante karakteren af protoner i interfacial vand, såsom quantum tunneling og nul-punkt motion.

<table border="0" cellpadding="0" cellspacing="0" style="width:632px;" width="633">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Au(111) single crystal</td>
			<td style="width:131px;">MaTeck</td>
			<td style="width:119px;">NA</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">NaCl</td>
			<td style="width:131px;">Sigma Aldrich</td>
			<td align="right">450006</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Water, deuterium-depleted&#160;</td>
			<td style="width:131px;">Sigma Aldrich</td>
			<td align="right">195294</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Deuterium oxide&#160;</td>
			<td style="width:131px;">Sigma Aldrich</td>
			<td align="right" style="width:119px;">364312</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Sealed-off glass-UHV adapters</td>
			<td style="width:131px;">MDC vacuum products</td>
			<td align="right" style="width:119px;">46300</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Diaphragm-sealed valve</td>
			<td style="width:131px;">any</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Bellows-sealed valve</td>
			<td style="width:131px;">any</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Leak valve</td>
			<td style="width:131px;">Kurt J. Lesker&#160;</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scanning tunneling microscopy</td>
			<td style="width:131px;">CreaTec</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Electronic controller.</td>
			<td style="width:131px;">Nanonis&#160;</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tungsten wire</td>
			<td style="width:131px;">any</td>
			<td style="width:119px;"></td>
			<td>diameter:0.3 mm; purity: 99.95%</td>
		</tr>
	</tbody>
</table>

probing the structure and dynamics of interfacial water with scanning tunneling microscopy and spectroscopy

Vand/solid grænseflader er allestedsnærværende og spille en central rolle i mange miljømæssige, biofysiske og teknologiske processer. Løse den interne struktur og sondering brint-bond (H-bond) dynamikken i de vandmolekyler adsorberet på faste overflader er grundlæggende spørgsmål om vand videnskab, som stadig er en stor udfordring på grund af lys masse og lille størrelse af brint. Scanning tunneling mikroskopi (STM) er et lovende redskab for at angribe disse problemer, takket være dens kapaciteter af sub-Ångström rumlige opløsning, single-bond vibrationelle følsomhed og atomar/Molekylær manipulation. Designet eksperimentelle systemet består af en Cl-afsluttet spids og en prøve fabrikeret af dosering vand molekyler i situ på Au (111)-understøttet NaCl(001) overflader. De isolerende NaCl film afkoble elektronisk vand fra de metal substrater, så iboende grænse-orbitaler af vandmolekyler bevares. Cl-tip letter manipulation af de indre vandmolekyler, samt gating orbitaler af vand til nærhed af Fermi niveau (EF) via tip-vand kobling. Dette papir beskriver de detaljerede metoder til submolecular opløsning imaging, Molekylær/atomic manipulation og single-bond vibrationelle spektroskopi interfacial vand. Disse undersøgelser åbner en ny rute for at undersøge de H-bonded systemer på atomar skala.

Figur 1 en illustrerer skematiske af STM eksperimentel opsætning. Første, Au(111) substrat er renset ved sputtering og udglødning cyklusser i UHV kammer. Ren Au(111) prøven viser 22 × √3 rekonstruerede overflade, hvor atomer af slidlaget besætte både hcp og fcc steder danner sildeben strukturer (indsatser af figur 1b). For NaCl er fordampet på Au(111) substrat, danner tolagede øer (<st...

Watch this Scientific Journal Video about Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy at JoVE.com

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Sondering struktur og dynamik Interfacial vand med Scanning Tunneling Mikroskopi og spektroskopi

Vi præsenterer her, en protokol for at undersøge strukturen og dynamikken i interfacial vand på atomar skala, submolecular opløsning imaging, Molekylær manipulation og single-bond vibrationelle spektroskopi.

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal ...

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This study discusses a synthesis route for soft polysiloxane-based urea (PSU) elastomers for their applications as accommodating intraocular lenses ...

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics

Multiscale prøveudtagning af en heterogene vand/Metal katalysator Interface ved hjælp af tæthed funktionelle teori og kraftfelt Molekylær dynamik

A significant number of heterogeneously-catalyzed chemical processes occur under liquid conditions, but simulating catalyst function under such conditions ...

Performing Spectroscopy on Plasmonic Nanoparticles with Transmission-Based Nomarski-Type Differential Interference Contrast Microscopy

Udfører spektroskopi på Plasmonic nanopartikler med transmission-baseret Nomarski-type differential interferens kontrast mikroskopi

Differential interference contrast (DIC) microscopy is a powerful imaging tool that is most commonly employed for imaging microscale objects using ...

Probing Surface Electrochemical Activity of Nanomaterials using a Hybrid Atomic Force Microscope-Scanning Electrochemical Microscope (AFM-SECM)

Probing Surface Electrochemical Activity of Nanomaterials using a Hybrid Atomic Force Microscope-Scanning Electrochemical Microscope AFM-SECM

Sondering Overflade elektrokemisk aktivitet af nanomaterialer ved hjælp af en Hybrid Atomic Force Mikroskop-Scanning elektrokemiske mikroskop (AFM-SECM)

Scanning electrochemical microscopy (SECM) is used to measure the local electrochemical behavior of liquid/solid, liquid/gas and liquid/liquid interfaces. ...

Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package

Analyse af smelter og væsker fra Ab Initio Molecular Dynamics Simulations med UMD-pakken

We have developed a Python-based open-source package to analyze the results stemming from ab initio molecular-dynamics simulations of fluids. The package ...

Atomic Force Microscopy Combined with Infrared Spectroscopy as a Tool to Probe Single Bacterium Chemistry

Atomprøvesprængningsmikroskopi kombineret med infrarød spektroskopi som et værktøj til sonde enkelt bakteriekemi

Atomic Force Microscopy-Infrared Spectroscopy (AFM-IR) is a novel combinatory technique, enabling simultaneous characterization of physical properties and ...

Preparation of Nanoparticles for ToF-SIMS and XPS Analysis

Forberedelse af nanopartikler til ToF-SIMS- og XPS-analyse

Nanoparticles have gained increasing attention in recent years due to their potential and application in different fields including medicine, cosmetics, ...