TY - JOUR

T1 - Isotope Effects in the Spectra of Hydrogen-Bonded Complexes. Experimental and Theoretical Study of an IR Absorption Spectrum of the (12CH3)213 CO…HF Complex

AU - Bulychev, V. P.

AU - Engalycheva, E. A.

AU - Tokhadze, K. G.

PY - 2019/4/1

Y1 - 2019/4/1

N2 - Abstract: IR absorption spectra of mixtures (12CH3)213CO/HF and free (12CH3)213CO molecules are recorded in the region of 4000−800 cm−1 with a Bruker IFS-125 HR vacuum Fourier spectrometer at room temperature with a resolution of 0.05 cm−1. Absorption bands of the (12CH3)213CO…HF complex are obtained by subtracting the absorption bands of free HF and acetone molecules and absorption lines of atmospheric water from the experimental spectrum of mixtures. Spectral characteristics of the 2ν(13C=O) overtone band of free acetone were also recorded. Comparison of the spectral data obtained with the analogous data measured earlier for the (12CH3)213CO…HF complex shows changes in the absorption spectra of complexes caused by 12C → 13C isotopic substitution. The frequencies and intensities for absorption bands of both complexes are calculated using the perturbation theory and methods MP2/6-311++G(2d,2p) and MP2/6-311++G(3df,3pd) with allowance for the error of superposition of basis functions of the monomers. The calculated results are in good agreement with the experimental data and are used to interpret the observed spectra. The influence of anharmonic effects on the frequencies and intensities of the strongest ν(H–F) and ν(13C=O) bands is examined with the help of variational calculations. It is shown that, unlike the (12CH3)213CO…HF complex, the 2ν(13C=O)/ν(H–F) resonance is virtually absent in the (12CH3)213CO…HF complex.

AB - Abstract: IR absorption spectra of mixtures (12CH3)213CO/HF and free (12CH3)213CO molecules are recorded in the region of 4000−800 cm−1 with a Bruker IFS-125 HR vacuum Fourier spectrometer at room temperature with a resolution of 0.05 cm−1. Absorption bands of the (12CH3)213CO…HF complex are obtained by subtracting the absorption bands of free HF and acetone molecules and absorption lines of atmospheric water from the experimental spectrum of mixtures. Spectral characteristics of the 2ν(13C=O) overtone band of free acetone were also recorded. Comparison of the spectral data obtained with the analogous data measured earlier for the (12CH3)213CO…HF complex shows changes in the absorption spectra of complexes caused by 12C → 13C isotopic substitution. The frequencies and intensities for absorption bands of both complexes are calculated using the perturbation theory and methods MP2/6-311++G(2d,2p) and MP2/6-311++G(3df,3pd) with allowance for the error of superposition of basis functions of the monomers. The calculated results are in good agreement with the experimental data and are used to interpret the observed spectra. The influence of anharmonic effects on the frequencies and intensities of the strongest ν(H–F) and ν(13C=O) bands is examined with the help of variational calculations. It is shown that, unlike the (12CH3)213CO…HF complex, the 2ν(13C=O)/ν(H–F) resonance is virtually absent in the (12CH3)213CO…HF complex.

KW - INFRARED-SPECTRUM

KW - HF COMPLEXES

KW - PARAMETERS

KW - CARBONYL

UR - http://www.scopus.com/inward/record.url?scp=85066486235&partnerID=8YFLogxK

U2 - 10.1134/S0030400X19040052

DO - 10.1134/S0030400X19040052

M3 - Article

AN - SCOPUS:85066486235

VL - 126

SP - 321

EP - 330

JO - OPTICS AND SPECTROSCOPY

JF - OPTICS AND SPECTROSCOPY

SN - 0030-400X

IS - 4

ER -