Sign In

Chapter 13

Molecular Vibrational Spectroscopy

Infrared (IR) Spectroscopy: Overview
Infrared (IR) Spectroscopy: Overview
When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation ...
IR Spectroscopy: Molecular Vibration Overview
IR Spectroscopy: Molecular Vibration Overview
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental ...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond ...
IR Spectrometers
IR Spectrometers
There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR ...
IR Spectrum
IR Spectrum
When infrared (IR) radiation passes through a molecule, the bonds stretch or bend by absorbing the radiation. This absorption creates the molecule's ...
IR Absorption Frequency: Hybridization
IR Absorption Frequency: Hybridization
Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching absorption bands. These IR stretching frequencies depend on ...
IR Absorption Frequency: Delocalization
IR Absorption Frequency: Delocalization
Electron delocalization refers to the distribution of electrons across multiple atoms within a molecule rather than being confined to a single atom or ...
IR Frequency Region: X–H Stretching
IR Frequency Region: X–H Stretching
In IR spectroscopy, signals produced by the X−H bonds (such as C−H, O−H, or N−H) can be observed in the frequency range of  ...
IR Frequency Region: Alkyne and Nitrile Stretching
IR Frequency Region: Alkyne and Nitrile Stretching
Both alkyne (C≡C) and nitrile (C≡N) functional groups contain triple bonds and show stretching absorptions around the wavenumber range of 2100 ...
IR Frequency Region: Alkene and Carbonyl Stretching
IR Frequency Region: Alkene and Carbonyl Stretching
Double bonds in alkenes and carbonyl compounds exhibit stretching frequencies in the diagnostic region of the IR spectrum. In addition, alkenes exhibit ...
IR Frequency Region: Fingerprint Region
IR Frequency Region: Fingerprint Region
IR spectra are divided into two main regions: the diagnostic region and the fingerprint region. The diagnostic region of the spectrum lies above 1500 ...
IR Spectrum Peak Intensity: Amount of IR-Active Bonds
IR Spectrum Peak Intensity: Amount of IR-Active Bonds
When infrared radiation is passed through a molecule, absorption occurs if the molecule's vibration leads to a substantial change in its bond dipole ...
IR Spectrum Peak Intensity: Dipole Moment
IR Spectrum Peak Intensity: Dipole Moment
The dipole moment of a bond is the product of the partial charge on either atom and the distance between them. Dipole moments influence the efficiency of ...
IR Spectrum Peak Broadening: Hydrogen Bonding
IR Spectrum Peak Broadening: Hydrogen Bonding
The vibrational frequency of a bond is directly proportional to its bond strength. As a result, stronger bonds vibrate at higher frequencies, while weaker ...
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these ...
Applications of IR Spectroscopy: Overview
Applications of IR Spectroscopy: Overview
The non-destructive nature and ability to provide valuable chemical information make IR spectroscopy a versatile technique with broad applications in ...
Attenuated Total Reflectance (ATR) Infrared Spectroscopy: Overview
Attenuated Total Reflectance (ATR) Infrared Spectroscopy: Overview
Attenuated total reflectance (ATR) infrared spectroscopy is a powerful analytical technique used to study the composition of materials. It is widely ...
Raman Spectroscopy: Overview
Raman Spectroscopy: Overview
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of ...
Raman Spectroscopy Instrumentation: Overview
Raman Spectroscopy Instrumentation: Overview
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector. The monochromatic laser ...
JoVE Logo

Privacy

Terms of Use

Policies

Research

Education

ABOUT JoVE

Copyright © 2025 MyJoVE Corporation. All rights reserved