The torsional spectrum of the hydrogen trioxide molecule

Abstract

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.

Torsional States and Tunneling Probability in HOSOH, DOSOD, and DOSOH Molecules Analyzed at the CBS Limit

“…It also presents the configuration of the molecule for which the values of the torsional coordinates γ 1 ,γ 2 of hydroxyl groups were set equal to zero. As shown earlier, − the HO­(CH 2 )­OH and HOOOH molecules, and therefore HOSOH molecule, belong to the molecular symmetry group C 2V ( M ), which includes four inverse permutation operations, ( E , (15)(24), E *, (15)(24)*), and the isomorphic point symmetry group is C 2V . Regardless of whether tunneling between configuration-equivalent states of conformers is present or absent, the potential energy must be the same at points with the following coordinates …”

“…The 2D surfaces of the kinematic coefficients calculated at the MP2/cc-pVQZ level of theory are presented in Figure 1 of the Supporting Information. Comparing the shape of the 2D PES and 2D surfaces of the components of the dipole moment of the methanediol (MD) , and hydrogen trioxide (HT) , molecules to the HOSOH molecule presented in Figures and helps to conclude that they are very similar. 2D surfaces of the kinematic coefficients F γ 1 γ 1 and F γ 2 γ 2 equivalent up to 90° rotation through an angle about an axis normal to the coordinate plane and passing through a point with coordinates (180, 180°).…”

“…Recently, we performed calculations of the torsional states of HO­(CH 2 )­OH and HOOOH molecules as well as their deuterated derivatives. , The torsional states were classified using the molecular symmetry group C 2V ( M ), and it was found that the calculated tunneling frequencies in these molecules differ significantly (by several orders of magnitude), but both of them can be assigned to nonrigid molecules. We confirmed that the stability of the cis-conformer in the first molecule is quite uncertain and can only be realized at very low temperatures.…”

“…We confirmed that the stability of the cis-conformer in the first molecule is quite uncertain and can only be realized at very low temperatures. Besides, it was shown that in the case of low values of tunneling frequencies, the correct procedure for calculating 2D PES and kinematic coefficients, as well as taking into account the molecular symmetry, is particularly important . In this study, using previously developed methods, − we calculated 2D potential energy surfaces and kinematic coefficients with a complete account of the properties of the molecular symmetry group C 2V ( M ), which describes the symmetry properties of both conformers of HOSOH and DOSOD molecules.…”

“…Besides, it was shown that in the case of low values of tunneling frequencies, the correct procedure for calculating 2D PES and kinematic coefficients, as well as taking into account the molecular symmetry, is particularly important . In this study, using previously developed methods, − we calculated 2D potential energy surfaces and kinematic coefficients with a complete account of the properties of the molecular symmetry group C 2V ( M ), which describes the symmetry properties of both conformers of HOSOH and DOSOD molecules. Then, the values of the energy of the stationary torsional states of three analyzed molecules were calculated and their torsional IR spectra were modeled at various temperatures.…”