Study on structure and potential energy function of the ground state for BeO molecule using coupled-cluster theory

The possible electronic states and their reasonable dissociation limits for BeO are determined based on the atomic and molecular reaction statics.The energy,equilibrium geometry and harmonic frequency of the ground state X 1∑+have been calculated.Using CI theory QCISD and CCSD(T)method at the basis sets of D95(3df,3pd),cc-PVQZ and 6-311G(3df,3pd),the whole potential curves for the ground state and scanned using CCSD(T)/ cc-PVQZ,have a least square fitted to Murrell-Sorbie function,and last spectroscopy Constants(Be,α e,ω e,and χe)are calculated,which are in good agreement with the experimental data.