Ab initio Calculated Rotation-Vibration Linestrengths for HeH2+

Together with the recently determined potential energy surface for the ground electronic state of HeH2+ [V. Spirko and W. P. Kraemer, J. Mol. Spectrosc. 172, 265-274 (1995)], the electric dipole moment components were calculated directly as expectation values with the corresponding length operators at the center of mass of the ion and using the variationally optimized configuration interaction wavefunctions. From the fitted potential energy and dipole moment functions all bound rotation-vibration energy levels and the line strengths of all dipole-allowed bound-bound transitions were evaluated variationally within the framework of the Sutcliffe-Tennyson Hamiltonian. Strong transitions, especially for the (He...H2)+ stretching motion, were obtained in the 500-800 cm-1 infrared frequency range. The present calculations demonstrate that the conditions for detecting the still unobserved rotation-vibration spectrum of HeH2+ are rather promising. Copyright 1997Academic Press