PROTONATION OF THE OZONE ANALOG S2O - STRUCTURES, ENERGIES AND VIBRATIONAL-SPECTRA OF HS2O+ ISOMERS

Protonation is a simple reaction that can both reveal and induce chang es in the electronic structure of molecules. The protonation of variou s S2O isomers: SSO, cyclic S2O, and SOS does not qualitatively change the underlying potential energy surface of these isomers. The protonat ed SSO isomers are lowest in energy, and cis-SSOH+ is the lowest of th ese. S-protonated and O-protonated cyclic S(2)0 are next highest in en ergy, with the S-protonated isomer slightly lower in energy than the O -protonated isomer. For SOS we find, contrary to previous results, tha t the lowest energy isomer is a B-3(2) rather than a (3)A(2) state. Pr otonated SOS, however, has a singlet ground state. Both geometry chang es and vibrational frequency changes upon protonation illustrate the n ature of the bonding in the various S2O isomers.