Theoretical investigation of ionized HSO and SOH

Abstract

The anharmonic force-fields of HSO+ and SOH+ have been determined employing the CCSD(T) methodology and the correlation consistent basis sets. The calculated fundamental frequencies of SOH+ are 1009, 1149 and 3317 cm−1, for the υSO, υbend and υOH, respectively. For HSO+ the computed fundamentals are 1060, 1190 and 2307 cm−1, for the υbend, υSO and υSH, respectively. The vibrational frequency observed at 1150 ± 160 cm−1 for HSO+, which was tentatively assigned to the bending-mode, is close to our computed value for the SO-stretching mode. Thus revision of the assignment is suggested. The computed ionization potentials for HSO and SOH are 9.933 and 10.096 eV, respectively. The former value is in excellent agreement with the experimental measurement, 9.918 ± 0.016 eV. The onset to triplet HSO+ is calculated at 11.115 eV, in reasonable agreement with the experimental value 11.15 ± 0.04 eV. To estimate the of HSO+ and SOH+ we considered relativistic, core-valence and higher-order correlation effects. The recommended values are (HSO+) = 223.6 ± 0.5 and (SOH+) = 230.7 ± 0.5 kcal/mol. Finally, employing the experimental ionization potential of HSO and the (HSO+) we recommend (HSO) = −5.5 ± 0.5 and (SOH) = −2.0 ± 0.5 kcal/mol.