The torsional states of methyl hydroperoxide molecule calculated using anharmonic zero point vibrational energy

Pitsevich, G. А.; Malevich, Alexander E.; Lazicki, Uladzimir V.; Sapeshka, Uladzimir

doi:10.33581/2520-2243-2021-2-15-24

Cited by 7 publications

(3 citation statements)

References 41 publications

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“…The vibrational Schrödinger equation of restricted dimensionality for two torsional coordinates has the form (8) [60][61][62][63]:…”

Section: Calculation Detailsmentioning

confidence: 99%

Torsional IR spectra of three conformers of the resorcinol molecule

Pitsevich,

Malevich

2023

Molecular Physics

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Conformational states, barriers to internal rotation, 2D potential energy surfaces, kinetic coefficients and dipole moment components of the resorcinol molecule are calculated at the MP2/CBS(T,Q), MP2/Aug-cc-pVTZ, MP2/dAug-cc-pVTZ and B3LYP/Aug-cc-pVTZ levels of theory. After symmetrization of the calculated data, they were approximated by the symmetryadapted sets of basis functions. Using the calculated data sets, the energies and wave functions of stationary torsional states were determined for the first time using a numerical solution of the vibrational Schrödinger equation of limited dimensionality. This made it possible to establish the values of the tunneling splitting of the ground vibrational and a number of excited torsional states of the energetically most preferred conformer of the molecule, belonging to the point symmetry group C S . The 100 lowest torsional states of the resorcinol molecule are classified according to the symmetry species of the molecular symmetry group C 2V (M), which unites all three conformers of the molecule. The calculations of the matrix elements of the dipole moment operator and the partition functions made it possible to simulate the torsional IR spectra of three conformers of the molecule at different temperatures. The calculated values of the frequency of the most intense torsional vibration in the most stable conformer of the molecule (316 and 320 cm -1 ), obtained at the MP2/dAug-cc-pVTZ and MP2/CBS(T,Q) levels of theory are in good agreement with the experimental value of the frequency of this vibrations (318 cm -1 ), obtained in [

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“…The vibrational Schrödinger equation of restricted dimensionality for two torsional coordinates has the form (8) [60][61][62][63]:…”

Section: Calculation Detailsmentioning

confidence: 99%

Torsional IR spectra of three conformers of the resorcinol molecule

Pitsevich,

Malevich

2023

Molecular Physics

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“…Previously, we have analyzed torsional states and IR spectra of a number of molecules with similar structure: HO(CH 2 )OH [16,17], HOOOH [18,19], HSOSH [20,21], HOSOH [22], C 6 H 4 (OH) 2 -ortho [23], CH 3 CH 2 OH [24], and CH 3 OOH [25]. Although the trans-conformers of all these molecules are energetically preferable to the cis-conformers, their relative energies differ significantly.…”

Section: Introductionmentioning

confidence: 99%

Modelling of the torsional IR spectra of the HSSSH, DSSSH, and DSSSD molecules

Pitsevich

Malevich

Sapeshka

et al. 2023

Computational and Theoretical Chemistry

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“…Recently, when calculating PES, some authors took into account zero-point vibrational energy (ZPVE). Sometimes it leads to an improvement in the agreement between calculated and experimental data, and sometimes it rather worsens the agreement between them [1,2]. To obtain more complete information on the efficiency of taking into account ZPVE, we have made a calculation of energy of stationary torsional states for hydrogen peroxide and methyl alcohol molecules with and without taking into account ZPVE.…”

mentioning

confidence: 99%

Is It Possible to Improve Theoretical Prediction of the Frequencies of the Torsional Vibrations by Accounting Zpve? Testing Most Simple Molecules

Sapeshka¹,

Kisuryna²,

Khrapunova³

et al. 2022

Proceedings of the 2022 International Symposium on Molecular Spectroscopy

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Torsional vibrations and internal rotation are the one kind of large amplitude motion in polyatomic molecules and clusters. It is well known that the standard approach within the frame of harmonic approximation to calculating the frequencies of torsional vibrations is unworkable. In this case, one must calculate full potential energy surface (PES) while varying torsional coordinates throughout all intervals of their determination. Recently, when calculating PES, some authors took into account zero-point vibrational energy (ZPVE). Sometimes it leads to an improvement in the agreement between calculated and experimental data, and sometimes it rather worsens the agreement between them [1,2]. To obtain more complete information on the efficiency of taking into account ZPVE, we have made a calculation of energy of stationary torsional states for hydrogen peroxide and methyl alcohol molecules with and without taking into account ZPVE. It is well known that there is much more experimental data about the energy of excited torsional states for these molecules than for any others. The calculations were performed on several levels of theory.

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The torsional states of methyl hydroperoxide molecule calculated using anharmonic zero point vibrational energy

Cited by 7 publications

References 41 publications

Torsional IR spectra of three conformers of the resorcinol molecule

Torsional IR spectra of three conformers of the resorcinol molecule

Modelling of the torsional IR spectra of the HSSSH, DSSSH, and DSSSD molecules

Is It Possible to Improve Theoretical Prediction of the Frequencies of the Torsional Vibrations by Accounting Zpve? Testing Most Simple Molecules

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