An IC-MRCI ansatz has been used in conjunction with augmented quadruple-ζ basis sets to construct an 89-point potential energy surface of the ground electronic state of BeH²₂⁺. The equilibrium structure was predicted to be of C₂v symmetry, possessing Be–H bond lengths of 1.609Å and a H–Be–H bond angle of 29.4˚. A rational Padé analytical function was fitted to the discrete IC-MRCI grid yielding a (x²)½ value of 5.20 cm⁻¹. It was embedded in the t-coordinate Eckart–Watson Hamiltonian to calculate vibrational and rovibrational wave functions. For the vibrational ground state, the vibration-averaged bond lengths and angle were 1.647Å and 29.2˚, respectively. An embedded analytical IC-MRCI dipole moment function fitted to 73 discrete points was transformed to the space-fixed frame. Rovibrational radiative properties were calculated using this surface in conjunction with a novel integration scheme.
Molecular Physics Vol. 105, Issue 19-22, p. 2527-2539