The isomerisation of H2XY to HXYH (X, Y = O, S, and Se)

• Published in: Molecular physics Vol. 119; no. 17-18
• Main Authors: Bralick, A. K., Abbott, B. Z., Douberly, G. E., Schaefer III, H. F.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 17.09.2021
• Subjects: chalcogens; Computational chemistry; isomerisation
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268976.2021.1976429

Oxywater(H OO) is an intermediate in the oxidation of hydrogen peroxide (HOOH), and along with its relatives H SS and H SeSe, plays an important role in atmospheric and biochemical processes. In this research, we study the isomerisation of H XY species to HXYH (X, Y = O, S, Se) using ab initio methods. Geometries and harmonic frequencies were obtained using both a scalar relativistic X2C-1e-CCSD(T) approach and non-relativistic CCSD(T) using an effective core potential on Se. A focal point approach was used to extrapolate electronic energies at CCSD(T)/aug-cc-pVTZ geometries to a CCSDT(Q)/CBS level of theory. The isomerisation reactions of H XX to HXXH have barriers of 6.6, 20.6, and 14.1 kcal mol and exothermicities of 45.8, 27.2, and 28.3 kcal mol for X=O, S, and Se, respectively. The isomerisation reactions of H OS and H SO to HOSH have barriers of 15.4 and 44.2 kcal mol and exothermicities of 36.2 and 17.7 kcal mol . The isomerisation reactions of H OSe and H SeO to HOSeH have barriers of 10.1 and 36.2 kcal mol and exothermicities of 33.5 and 31.7 kcal mol . The isomerisation reactions of H SSe and H SeS to HSSeH have barriers of 16.2 and 18.1 kcal mol and exothermicities of 23.3 and 32.1 kcal mol .