Nonempiric Anharmonic Computations of IR Spectra of Ethanol Conformers in B3LYP/сс-pVQZ Approximation (Stretch С-Н Vibrations)

Abstract

Low-temperature FTIR spectra of ethanol in the argon matrix have been recorded in the spectral interval 2800-4000 cm-1. The spectra were obtained for several temperatures over the range 20-50 К and for the number ratios 1:1000 and 1:2000 of the molecules studied and atoms in the matrix. A tentative interpretation has been performed on the basis of the temperature and concentration changes in FTIR spectra with the use of the relevant literature data. The computations of harmonic and anharmonic IR spectra for gauche - and trans-rotamers of the ethanol molecule and its two deuterated derivatives (СD3CH2OH and CH3CD2OH) have been carried out in the approximation B3LYP/cc-pVQZ. An interpretation of the bands and lines in the region of stretching С-Н vibrations has been proposed with regard to the anharmonicity effects and Fermi resonances using the literature data on IR and Raman spectra of the molecule under study.