Geometries and energies of electronic states of AsH3, SbH3, and BiH3 and their positive ions

Geometries, potential energy surfaces, bond energies, dipole moments, ionization potentials and other properties of MH3 and MH+3 species (M=As, Sb and Bi) are obtained using complete active space self-consistent field (CASSCF) followed by full second-order configuration interaction (SOCI) and relativistic configuration interaction (RCI) methods. Potential energy surfaces of six electronic states of AsH3 and SbH3 and three states of BiH3 are obtained. The ground states of MH3 species are found to be of X 1A1 symmetries (C3v) with pyramidal geometries. The geometrical and other parameters of MH3 species are AsH3[re=1.517 Å, θe=92.2°, D(H2As–H)=74.6 kcal/mol, IP=9.5 eV], SbH3[re=1.719 Å, θe=91.5°, D(H2Sb–H)=63.3 kcal/mol, IP=8.9 eV], BiH3[re=1.865 Å, θe=90.3°, D(H2Bi–H)=51.8 kcal/mol, IP=9.0 eV]. The equilibrium geometries of MH+3 ions are found to be close to planar. For AsH3 the agreement in IP and bond energy between the present theoretical results and the experimental values obtained recently by Berkowitz [J. Chem. Phys. 89, 7065 (1988)] is excellent.