Spectroscopic properties and potential energy surfaces of GeH

Abstract

MCSCF (complete active space SCF) followed by configuration interaction calculations are carried out on 12 electronic states of GeH. Relativistic configuration interaction calculations are carried out with the objective of computing the spin-orbit corrections for the low-lying states. These calculations reveal the existence of 10 bound electronic states of GeH for which spectroscopic properties are computed. The three experimentally observed bands ( a- X, A- X, B- X) are assigned and the uncertainties in the experimental T e and ω e values of these states are corrected. In addition, the spectroscopic properties of 8 states are calculated which are yet to be observed. The spin-orbit coupling constant for the ground state X( 2 Π) is calculated to be 869 cm −1. An accurate dissociation energy of 2.81 eV was obtained using MCSCF SOCI calculation which employed a large Gaussian basis set questioning the experimental D e of ∼3.3 eV obtained from the predissociation in the A 2Δ state. It is shown that the intersection of the repulsive 4Π curve which dissociates into the ground state atoms causes predissociation in the A( 2 Δ) , B( 2 Σ + ) , 2Σ +(III), and 2Π(II) states. The potential energy surfaces of a few excited states contain barriers. The calculated ground state dipole moment of 0.098 D is in disagreement with an experimental value of 1.24 D, questioning the experimental dipole moment.