Electronic states and potential energy surfaces of H2Te, H2Po, and their positive ions

Abstract

Geometries, bond energies, ionization potentials, dipole moments, other one-electron properties, and potential energy surfaces of six valence electronic states of H2Te and H2Po species are obtained using the relativistic complete active space multiconfiguration self-consistent field (CASSCF) followed by full second-order configuration interaction (SOCI) and relativistic configuration interaction (RCI) calculations including spin–orbit coupling. In addition, Rydberg states of H2Te and H2Se are studied to interpret the experimental spectra. The potential energy surfaces of two electronic states of H2Te+ and H2Po+ are obtained. The ground states of both H2Te and H2Po are found to be of X 1A1(A1) symmetry with bent (C2v) equilibrium geometries of H2Te:re=1.668 Å, θe=91.2°; and H2Po:re=1.835 Å and θe=90.9°. The ground states of H2Te+ and H2Po+ are X 2B1 with H2Te+:re=1.676 Å, θe=90.7° and H2Po+:re=1.828 Å and θe=88°. The De (HTe–H) and De (HPo–H) including spin–orbit effects are calculated as 63.2 and 39.4 kcal/mol, respectively. The X 2B1(E)−A 2A1(E) energy separations of H2Te+ and H2Po+ ions are calculated as 66.6 and 76 kcal/mol, respectively. The adiabatic IPs of H2Te and H2Po are calculated as 8.47 and 7.79 eV, respectively. In addition CASSCF/SOCI/RCI calculations are also carried out on the X 2Π3/2 and 2Π1/2 states of TeH and PoH diatomics. The X 2Π3/2–2Π1/2 energy separations of TeH and PoH are computed as 3710 and 9920 cm−1, respectively. Spin–orbit effects are thus found to be very significant for PoH and H2Po. All excited states of H2Te and H2Po are above 3.7 and 3.1 eV, respectively. Properties and energy separations of H2Te and H2Po are compared with the lighter group (VI) H2Ch species.