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

Abstract

Torsional vibrations of a sulfoxylic acid molecule (HOSOH) and its two deuterated isotopologues were analyzed for the first time. Harmonic and anharmonic calculations of the vibrational frequencies of the trans- and cis-conformers were performed. More rigorous consideration of the torsional vibrations was made based on 2D potential energy and kinematic coefficient surface calculations. These calculations were made at the MP2/cc-pVTZ and MP2/cc-pVQZ levels of theory, and then the results were extrapolated to the complete basis set limit. The 2D surface of the zero-point vibrational energy of a sulfoxylic acid molecule was calculated at the MP2/cc-pVTZ level of theory in anharmonic approximation and taken into account. The energies of the torsional states were found by numerical solution of the vibrational Schrödinger equation of the restricted dimensionality using the Fourier method. 2D surfaces of the dipole moment components were calculated too. Using all these data, the torsional IR spectra of the trans- and cis-conformers of the HOSOH, DOSOD, and DOSOH molecules were also modeled at different temperatures.

Successive Hydrogenation of SO and SO2 in Solid para-H2: Formation of Elusive Small Oxoacids of Sulfur

“…The barrier height between the forms is computed to be less than 35 kJ mol –1 (or approximately 2900 cm –1 , Figure and Table S46 in the Supporting Information). Therefore, the IR source of the spectrometer can generate a higher energy conformer in situ . Similar to the HS­(O)­OH system, it also applies that their computed vibrational frequencies lie too close to each other to safely distinguish between them.…”

“…Therefore, the IR source of the spectrometer can generate a higher energy conformer in situ. 145 Similar to the HS(O)OH system, it also applies that their computed vibrational frequencies lie too close to each other to safely distinguish between them.…”

Potential and kinetic interaction of two internal tops in molecules belonging to C2v(M) molecular symmetry group

“…Among them, noteworthy works [48][49][50][51] in which the structure, conformational composition and spectroscopic constants of the molecules HSSSH [48,49], HOSOH [50], and HOOOH [51] are analyzed. The experimentally determined values of rotational constants, potential barriers and relative energies of molecular conformers are in good agreement with the calculated values in the above-mentioned works [7,35,33,34]. However, in the experimental works noted above, it was not possible to detect the splitting of spectral lines due to tunneling between equivalent configurations of molecular conformers.…”

“…We have previously calculated the two-dimensional PES and torsional spectra of several molecules containing two hydroxyl groups (HO(CH 2 )OH (II) [31,32], HOOOH (III) [33,34], HOSOH (IV) [35] and C 6 H 4 (OH) 2-ortho (I) [36]), as well as two molecules containing two thiol internal tops (HSOSH (V) [37] and HSSSH (VI) [7]). All calculations for the molecules listed above were performed at the MP2/CBS(T,Q) [38][39][40][41][42] level of theory.…”

Torsional IR spectra of three conformers of the resorcinol molecule

“…Let us recall that the RES molecule belongs to the same molecular symmetry group (C 2V (M)) as the CTL molecule. Previously, we calculated the torsional IR spectra of a number of molecules (HO(CH 2 )OH, HOOOH, HOSOH, HSOSH, HSSSH) belonging to this molecular symmetry group [37][38][39][40][41]. Based on an analysis of literature data and relying on the experience gained from analyzing torsional vibrations of similar molecules, we performed calculations of the torsional states of the RES molecule.…”