AB-INITIO CALCULATIONS OF THE ROTATIONALLY RESOLVED INFRARED-SPECTRUMOF KNA2+

Ab initio variational calculations were performed on the rotationally resolved infrared spectrum of KNa2+. A discrete potential energy surfa ce was generated using the configuration interaction ansatz coupled wi th the frozen core approximation, from which an analytical representat ion was obtained using a power series expansion employing a Dunham exp ansion variable. This force field was embedded in an Eckart-Watson rov ibrational Hamiltonian, from which eigenfunctions and eigenenergies we re calculated. An SCF dipole moment surface was generated and used to calculate absolute fine intensities and square dipole matrix elements between the vibrational ground state and the lowest-lying excited stat es for some of the most intense transitions within the P, Q and R bran ches.