Wydział Chemii

Krzysztof B. Beć

Justyna Grabska

Christian W. Huck

Mirosław A. Czarnecki

2019

Molecules

24

2189/1-2189/23

10.3390/molecules24112189

Naukowa

Angielski

Artykuł

The effect of isotopic substitution on near-infrared (NIR) spectra has not been studied in
detail. With an exception of few major bands, it is dicult to follow the spectral changes due to
complexity of NIR spectra. Recent progress in anharmonic quantum mechanical calculations allows
for accurate reconstruction of NIR spectra. Taking this opportunity, we carried out a systematic
study of NIR spectra of six isotopomers of ethanol (CX3CX2OX; X = H, D). Besides, we calculated
the theoretical spectra of two other isotopomers (CH3CD2OD and CD3CH2OD) for which the
experimental spectra are not available. The anharmonic calculations were based on generalized
vibrational second-order perturbation theory (GVPT2) at DFT and MP2 levels with several basis
sets. We compared the accuracy and eciency of various computational methods. It appears that
the best results were obtained with B2PLYP-GD3BJ/def2-TZVP//CPCM approach. Our simulations
included the first and second overtones, as well as binary and ternary combinations bands. This way,
we reliably reproduced even minor bands in the spectra of diluted samples (0.1 M in CCl4). On this
basis, the eect of isotopic substitution on NIR spectra of ethanol was accurately reproduced and
comprehensively explained.

near-infrared spectroscopy, ethanol, anharmonic quantum mechanical calculations, isotopic substitution, Overtones, combinations bands

CC-BY

http://dx.doi.org/10.3390/molecules24112189

http://www.mdpi.com/journal/metals