ClF diatomic molecule: rovibrational spectra

TL;DR

This paper develops an analytic Born-Oppenheimer potential for ClF's ground state, accurately modeling rovibrational spectra across all internuclear distances and predicting a large number of rovibrational states and van der Waals constant.

Contribution

It introduces a novel two-point Pade approximant for the ClF ground state potential, covering the entire internuclear distance range and supporting extensive rovibrational state calculations.

Findings

Supports 5719 rovibrational states with high vibrational and angular momentum quantum numbers.

Predicts the van der Waals constant C6 for ClF as approximately 29.3 a.u.

Includes 36 weakly-bound states near the dissociation threshold.

Abstract

Following the first principles the analytic Born-Oppenheimer (BO) potential curve for the ground state $X^1\Sigma^+$ of the molecule ClF is proposed for whole range of internuclear distances $R \in [0,\infty)$. It is based on matching the perturbation theory at small internuclear distances $R$ and multipole expansion at large distances $R$, it has the form of two-point Pade approximant and provides 3-4 figures in rovibrational energies. It supports 5719 rovibrational states with maximal vibrational number $\nu_{max} = 47$ and maximal angular momentum $L_{max} = 210$ including 36 weakly-bound states close to threshold (to dissociation limit) with the energies $\lesssim 10^{-4}$ Hartree. The van der Waals constant $C^{(ClF)}_6\ \sim\ 29.3$ a.u. is predicted.