title: Coupled-Cluster Study of the Lower Energy Region of the Ground Electronic State of the HSO2 Potential Energy Surface.
abstract: This work reports CCSD(T)/aug-cc-pV(T+d)Z ab initio calculations for the lower energy region of the ground electronic state of the HSO2 system. Optimized geometries, total energies, zero-point vibrational energies, frequencies, complete basis set extrapolations, and reaction paths are reported at the same level of calculation. The connection of the two minima (synperiplanar HOSO and HSO2) with the dissociation limit H + SO2 through the van der Waals minimum H···SO2 was established. An important quantitative discrepancy with previous works is the fact that at the present level of calculation the energy difference between transition states connecting the global minimum synperiplanar HOSO to the HSO2 minimum (TS5) and to the van der Waals minimum H···SO2 (TS6) is negligible, implying that the forward barriers after the synperiplanar HOSO global minimum have practically the same height. This result suggests that these two transition states may be involved in the path of the global minimum toward the exit channel H + SO2. As a consequence, trajectories for the OH + SO collisions could evolve through the well formed by the HSO2 minimum, therefore opening two competitive channels for the OH + SO → H + SO2 reaction, a fact never reported in trajectory calculations.
authors.affiliation: †Faculdade União das Américas, Foz do Iguaçu, PR 85870-901, Brazil.
authors.forename: Diana
authors.initials: D
authors.lastname: Rodríguez-Linares
authors.affiliation: ‡Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-909, Brazil.
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Freitas
authors.affiliation: §Departamento de Física, Universidade Federal de Juiz de Fora-UFJF, Juiz de Fora, MG 36036-330, Brazil.
authors.forename: Maikel Y
authors.initials: MY
authors.lastname: Ballester
authors.affiliation: ‡Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-909, Brazil.
authors.forename: Marco Antonio Chaer
authors.initials: MA
authors.lastname: Nascimento
authors.affiliation: ∥Centro Interdisciplinar de Ciências da Natureza, Universidade Federal da Integração Latino-Americana, Foz do Iguaçu, PR 85867-970, Brazil.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Garrido