Ab initio rovibrational spectra of [image omitted], BeHD2+ and [image omitted].

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 [image omitted]. The equilibrium structure was predicted to be of C2v symmetry, possessing Be-H bond lengths of 1.609 Å 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 [image omitted] 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 1.647 Å 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. [ABSTRACT FROM AUTHOR]