Ab Initio Vibration And Ro-Vibrational Spectrum Of The (1)A(1) State Of He2si2+

The low-lying ro-vibrational states for the ground electronic state ((1)A(1)) of HeSi2+ have been calculated using an ab initio variational solution of the nuclear Schrodinger equation. A 96 point CCSD(T)/cc-pCVQZ potential energy surface (PES) has been calculated and a Ogilvie-Pade (3,6) potential energy function has been generated. This force field was embedded in the Eckart-Watson Hamiltonian from which the vibrational and ro-vibrational eigenfunctions and eigenenergies have been variationally calculated. A 70 point QCISD/aug-cc-pCVTZ discrete dipole moment surface (DMS) was calculated and a 5th order power series expansion (in terms of the two bond lengths and the included bond angle) has been generated, Absolute line intensities have been calculated and are presented for some of the most intense transitions between the vibrational ground state and the low-lying ro-vibrational states of this ion. (C) 2002 Elsevier Science B.V. All rights reserved.