Ab initio study ground-state potential energy function of SiCl+

The potential energies at different internuclear distances for the ground electronic state of SiCl+ molecule are calculated using valence internally contracted multireference configuration interaction (MRCI) method and three large basis sets (aug-cc-pvtz, aug-cc-pvqz, and aug-cc-pv5z). The potential energies are extrapolated to the complete basis sets limit (CBS). It is found that the Si++Cl is the dissociation product of the ground state. The computational energies of potential energy curve (PEC) are fitted to analytical potential energy function (APEF) using generalized function and Murrell-Sorbie potential function. Based on the APEF, 2-8 order force constants are calculated, and spectroscopic constants are determined with Dunham formula. Then, vibrational terms and line positions of four isotopomers are determined by solve ro-vibrational Schrödinger equation with the APEF. All the theoretical results are compared with experimental data available at present.