Study on the potential energy function for the ground state （X1Σ+）of SiO molecule by density functional theory

Abstract

The structural optimization for the ground state (X1Σ+) of SiO molecule has been calculated using density functional theory B3P86 method with the basis sets STO-3G, D95**, 6-311G, 6-311++G, 6-311++G** and cc-PVTZ. The conclusion is draun by comparison that the basis set cc-PVTZ is the most suitable for the structural optimization calculation of the ground state (X1Σ+) of SiO molecule. The analytical potential energy curve for the ground state (X1Σ+) of SiO molecule is scanned using B3P86/cc-PVTZ method, and then fitted to the Murrell-Sorbie function using least squares. At last the spectroscopy constants (Be，αe，ωe and ωeχe) related to the analytical potential energy function are calculated and compared with the experimental data.