Overtone spectroscopy of v(C=O) stretching vibration of hexafluoroacetone: Experimental and ab initio determination of peak positions, absolute intensities, and band shapes

Krasnoshchekov, S. V.; Laptev, V. B.; Климин, С. А.; Gainullin, I. K.; Макаров, А. А.

doi:10.1016/j.saa.2020.118396

Cited by 7 publications

(2 citation statements)

References 54 publications

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“…IVR is due to anharmonic coupling between different vibrational modes. Using ab initio molecular dynamics methods at the B3LYP-D3/def2-SVP level of theory, we find the relevant time scale to be ∼3.5 ps, comparable to what has been found for the C─O stretch mode in hexafluoroacetone (34) and sufficiently large for the coherent pump-probe spectroscopy that we suggest.…”

Section: Discussionsupporting

confidence: 83%

Pump-probe spectroscopy of chiral vibrational dynamics

et al. 2022

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A planar molecule may become chiral upon excitation of an out-of-plane vibration, changing its handedness during half a vibrational period. When exciting such a vibration in an ensemble of randomly oriented molecules with an infrared laser, half of the molecules will undergo the vibration phase-shifted by π compared to the other half, and no net chiral signal is observed. This symmetry can be broken by exciting the vibrational motion with a Raman transition in the presence of a static electric field. Subsequent ionization of the vibrating molecules by an extreme ultraviolet pulse probes the time-dependent net handedness via the photoelectron circular dichroism. Our proposal for pump-probe spectroscopy of molecular chirality, based on quantum-chemical theory and discussed for the example of the carbonyl chlorofluoride molecule, is feasible with current experimental technology.

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Section: Discussionsupporting

confidence: 83%

Pump-probe spectroscopy of chiral vibrational dynamics

et al. 2022

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“…предыдущих исследованиях [62][63][64][65][66][67][68][69]. Для графического моделирования итоговых спектров для пика с энергией перехода E j и ИК интенсивностью I (IR) j…”

Section: методика расчетаunclassified

Неэмпирический анализ изотопических сдвигов и резонансных эффектов в инфракрасном спектре высокого разрешения фреона-22 (CHF-=SUB=-2-=/SUB=-Cl), обогащенного -=SUP=-13-=/SUP=-C

Краснощеков¹,

Гайнуллин²,

Лаптев³

et al. 2022

Оптика И Спектроскопия

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The IR transmittance spectrum of an isotopic mixture of chlorodifluoromethane (CHF2Cl, Freon-22) with a 33% fraction of 13C and a natural ratio of chlorine isotopes was measured in the frequency range 1400-740 cm–1 with a resolution of 0.001 cm–1 at a temperature of 20C. An ab initio calculation of the structure and sextic potential energy surface and surfaces of the components of the dipole moment has been carried out by the the electronic quantum-mechanical method of Möller-Plesset, MP2/cc-pVTZ. Then the potential was optimized by replacing the harmonic frequencies with the frequencies calculated by the electronic method of coupled clusters, CCSD(T)/aug-cc-pVQZ. The fundamental and combination frequencies were calculated using the operator perturbation theory of Van Vleck (CVPTn) of the second and fourth order (n=2,4). Resonance effects were modeled using an additional variational calculation in the basis up to fourfold VCI excitation (4). The average prediction error for the fundamental frequencies of the 12C isotopologues was ~1.5 cm–1. The achieved accuracy made it possible to reliably predict the isotopic frequency shifts of the 13C isotopologues. It is shown that the strong Fermi resonance ν4/2ν6 dominates in the 12C isotopologues and is practically absent in 13C. The literature assumption [Spectrochim. Acta A, 44: 553] about the splitting of ν1 (CH) due to the resonance ν1/ν2+ν7+ν9 is confirmed. The coefficients of the polyadic quantum number are determined. The analysis made it possible to carry out a preliminary identification of the centers of the vibrational-rotational bands of isotopologues 13CHF235Cl и 13CHF237Cl in the spectrum of the mixture in preparation for individual analyzes of the vibrational-rotational structures of individual vibrational transitions.

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