Spectroscopic Parameters And Potential Energy Function For Ground State Of Small Clusters Of Li,B And Be,H

Molecular potential energy function is one of the important research fields in atomic and molecular physics. It gives one absolute description of molecular and electronic energy with Born-Oppenheimer approximation, namely molecular energy, geometry, force constants and spectrum properties. At the same time, it is also the potential energy function of the core moving, which is basic to study atomic and molecular collision and reaction.The possible electronic states and the reasonable dissociate limits for the ground states of BeH,BeF,BeO, and BeCl have been derived based on the Atomic and Molecular Reaction Statics and the resolution of group representations by Gaussian 03. The molecular structures and harmonic frequencies for the ground states of them have been optimized based on the Density Functional Theory Method B3LYP, B3P86 and Quadratic CI calculation method (QCISD QCISD(T) method) and coupled-cluster theory(CCSD, CCSD(T)), using many basis sets. Comparing the attained results with the experiments, the most suitable method and basis set for each of them has gained. Based on these, the potential energy curves for the ground states of LiH, BH,BeF,BeO and BeCl have further scanned, then has a least-square fitted to the analytic Murrell-Sorbie function form, and the force constants for each of them are calculated, the spectroscopy data for the ground states have been also calculated. Results show that there are in good agreement among the calculations and the least-square fitting data.