Chapter 13
Molecular Vibrational Spectroscopy
Espectroscopia de infravermelho (IR): Visão geral
When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation ...
Espectroscopia IR: Visão geral da vibração molecular
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental ...
Espectroscopia IR: Aproximação da Vibração Molecular da Lei de Hooke
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond ...
Espectrômetros IR
There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR ...
Espectro IR
When infrared (IR) radiation passes through a molecule, the bonds stretch or bend by absorbing the radiation. This absorption creates the molecule's ...
Frequência de absorção de infravermelho: hibridização
Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching absorption bands. These IR stretching frequencies depend on ...
Frequência de absorção de infravermelho: deslocalização
Electron delocalization refers to the distribution of electrons across multiple atoms within a molecule rather than being confined to a single atom or ...
Região de frequência IR: Alongamento X–H
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 ...
Região de frequência IR: alongamento de alcino e nitrilo
Both alkyne (C≡C) and nitrile (C≡N) functional groups contain triple bonds and show stretching absorptions around the wavenumber range of 2100 ...
Região de frequência IR: alongamento de alceno e carbonila
Double bonds in alkenes and carbonyl compounds exhibit stretching frequencies in the diagnostic region of the IR spectrum. In addition, alkenes exhibit ...
Região de frequência IR: região de impressão digital
IR spectra are divided into two main regions: the diagnostic region and the fingerprint region. The diagnostic region of the spectrum lies above 1500 ...
Intensidade de pico do espectro IR: quantidade de ligações ativas IR
When infrared radiation is passed through a molecule, absorption occurs if the molecule's vibration leads to a substantial change in its bond dipole ...
Intensidade de pico do espectro IR: momento de dipolo
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 ...
Alargamento do Pico do Espectro IR: Ligação de Hidrogênio
The vibrational frequency of a bond is directly proportional to its bond strength. As a result, stronger bonds vibrate at higher frequencies, while weaker ...
Divisão de pico do espectro IR: vibrações simétricas vs assimétricas
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these ...
Aplicações da espectroscopia IR: visão geral
The non-destructive nature and ability to provide valuable chemical information make IR spectroscopy a versatile technique with broad applications in ...
Espectroscopia de infravermelho de refletância total atenuada (ATR): visão geral
Attenuated total reflectance (ATR) infrared spectroscopy is a powerful analytical technique used to study the composition of materials. It is widely ...
Espectroscopia Raman: Visão geral
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of ...
Instrumentação de espectroscopia Raman: visão geral
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser ...
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