The H3O Rydberg radical Original Research Article

Ab-initio calculations on the CEPA level are presented for the wave functions of a number of electronic states of the Rydberg radical H3O. We make predictions for wavelengths and transition probabilities of the vertical emission spectrum of Rydberg excited H3O∗ as well as for their equilibrium geometries. Furthermore we have investigated possible dissociation paths of some low-lying final electronic states. Three semivalence electronic states are thermodynamically unstable: The 3sa1 ground state has an adiabatic IP of about 5.4 eV and a barrier to dissociation of less than 0.1 eV whereas for the components of 3pe, connected by conical intersections, the IP is 3.3 eV and the barrier about 0.8 eV.