Ab initio diabatic and adiabatic calculations for francium hydride FrH

Abstract

Explicit ab initio diabatic and adiabatic calculations of potential energy curves (PECs) of the states ^1,3Σ⁺, ^1,3Π, and ^1,3Δ of francium hydride FrH have been carried out with several approaches. We determined for both representations the permanent and the transition dipole moment (PDM and TDM) and the vibrational levels. The calculation was based on the configuration interaction (CI) method, which includes effective core potentials (ECP) and core polarization potentials (CPP). The FrH system is considered as an effective two-electron system, permitting calculation of structural and electronic properties with full configuration interaction (FCI). For the diabatisation method, we perform an efficient diabatisation approach which depends on variational effective Hamiltonian theory (VEH) and a dynamic overlap matrix. This study complete the diabatic and adiabatic ab initio spectroscopic investigations of the series of all the alkali hydrides. In addition, we present our adiabatic results of FrH by comparing it with other alkali hydride systems (Li-Cs)H. This study is essential for a wide range of theoretical and experimental work.