AB-INITIO CHARACTERIZATION OF GASEOUS (HNP(O)(O)C)(+) SPECIES

Accurate ab initio G1 and G2 protocols have been used to characterize 14 [GRAPHICS] with n = 1-4, species. We have predicted that the C-site protonation of the earlier characterized [GRAPHICS] (B-2(1)) species is preferred over the P-site by 1.73 eV at the G2 level. For the [GRAP HICS] system, five stable molecular structures have been found fur eac h of the singlet and triplet spin multiplicities. In particular, the [ GRAPHICS] singlet isomers du not present either biradicaloid character or P-C cross bonding, while both the [GRAPHICS] and [GRAPHICS] single t molecules are almost pure biradical species with no P-C cross bondin g. For every case the singlet state has been found to be more stable t han the triplet. Finally, vibrational spectra of these species, which may help in their detection, are discussed.