Exact quantum mechanical kinetic energy operator in valence coordinates for internal motions of a polyatomic molecule

Makarewicz, Jan; Skalozub, A. S.

doi:10.1016/s0009-2614(99)00466-2

Cited by 27 publications

(17 citation statements)

References 21 publications

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“…The vibrational Schrӧdinger equation with reduced dimensionality has the form (2). It was solved numerically and the values of the energies of the stationary torsional levels were calculated [21][22][23][24][25][26]…”

Section: Calculation Detailsmentioning

confidence: 99%

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

Pitsevich

Malevich

Lazicki³

et al. 2021

Journal of the Belarusian State University. Physics

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The 2D surfaces of potential energy, kinematic coefficients, components of the dipole moment, the heights of potential barriers, the energies of stationary torsional states, and the tunneling frequencies of hydroxyl and methyl groups in the methyl hydroperoxide molecule were calculated at MP2/CBS and CCSD(T)/Aug-cc-pVTZ levels of theory. Additionally, calculations of the 2D surface of zero point vibrational energy of the molecule in the harmonic and anharmonic approximations were performed at MP2/Aug-cc-pVTZ level of theory. The zero point vibrational energy calculated in two approximations is summed up with the potential energy of the methyl hydroperoxide molecule, calculated at two levels of theory, and the resulting four outcomes of the refined potential energy are used to calculate the energies of stationary torsional states and tunneling frequencies. The results obtained are compared with the experimental and theoretical data presented in the literature to evaluate the efficiency of taking into account the zero point vibrational energy when examining the internal rotation in molecules.

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Section: Calculation Detailsmentioning

confidence: 99%

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

Pitsevich

Malevich

Lazicki³

et al. 2021

Journal of the Belarusian State University. Physics

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“…Configurations optimized in each node were used to calculate the kinematic coefficients using Wilson vectors ( s -vectors) [53]. The vibrational Schrödinger equation with reduced dimensionality for the torsional vibrations of two hydroxyl groups can be written as follows [43,[54][55][56]:…”

Section: Calculation Detailsmentioning

confidence: 99%

The torsional spectrum of the hydrogen trioxide molecule

2020

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The energies of the stationary torsional levels of the hydrogen trioxide molecule were calculated at the B3LYP, MP2, and CCSD(T) levels of theory using augmented correlation consistent acc-pVTZ basis set. The molecular symmetry group whose elements are inherent to both equilibrium conformer's symmetry elements (C2 and CS) of the HT molecule was found.Different methods of the molecular parameters calculations were suggested and analyzed. The torsional, spin and total wave functions were classified by irreducible representations of the C2V(M) molecular symmetry group. The 2D dipole moment surface was calculated too. The energies of the stationary torsional states were found using DVR and Fourier methods. With this and acceptable combinations of spatial and spin wave functions, the IR torsional spectrum was calculated at different temperatures. The tunneling frequencies in the ground and some excited torsional states were estimated too.

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“…Configurations optimized in each node were used to calculate the kinematic coefficients using Wilson's vectors ( s -vectors) [24]. The Schrödinger equation with reduced dimensionality for the torsional vibrations of two hydroxyl groups can be written as follows [25][26][27]:…”

Section: Calculation Detailsmentioning

confidence: 99%

The hydroxyl groups internal rotations in a methanediol molecule

Pitsevich

Malevich

Sapeshko

2019

Journal of Molecular Spectroscopy

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Internal rotation of two of hydroxyl groups in a methanediol molecule is analyzed by constructing the 2D surfaces of the potential energy, kinematic coefficients and dipole moment.The molecular characteristics in the nodes of 2D grids with different densities for distinct pairs of dihedral angles of O-H groups were calculated at the MP2/cc-pVQZ level of theory with optimization of the geometry for all other structural parameters. For optimized at the MP2/cc-pVQZ level of theory geometries, the potential energy was additionally calculated at the MP2/cc-pVTZ level of theory in the same grid nodes and then the extrapolation of energies in every node to the complete basis set limit was performed. The kinematic parameters were calculated using the formalism of the Wilson vectors. The Hamiltonian matrix was compiled using the DVR method. As a result of its diagonalization, the wave functions and energies of stationary torsional states were determined. The calculated torsional wave functions were classified by irreducible representations of the C 2V (M) molecular symmetry group. The frequencies and intensities of the torsional spectrum of a methanediol molecule were calculated at different temperatures for the trans-and cis-conformers. The tunneling frequencies for both conformers were calculated too.

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Exact quantum mechanical kinetic energy operator in valence coordinates for internal motions of a polyatomic molecule

Cited by 27 publications

References 21 publications

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

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

The torsional spectrum of the hydrogen trioxide molecule

The hydroxyl groups internal rotations in a methanediol molecule

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