Spectroscopic investigations on cometary molecules CO +, CH and CH +

Abstract

The experimental potential energy curves for the electronic ground states of molecules like CO +, CH and CH + observed in comets are constructed by using the Rydberg–Klein–Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting technique using the five parameter Hulburt–Hirschfelder (H–H) function. The estimated dissociation energies are 8.33±0.19, 3.48±0.903 and 3.89±0.102 eV for CO +, CH and CH +, respectively. These values are in good agreement with the literature values. Estimated dissociation energies of CO +, CH and CH + are used in the relation given by Gaydon and ionization potentials are evaluated for CO and CH molecules. The estimated ionization potentials are 14.03 and 10.85 eV , respectively for CO and CH. The Franck–Condon factors and r-centroids for the band system of A 2 Π – X 2 Σ + of CO + molecule have been calculated employing an approximate analytical methods of Jarmain and Fraser. The absence of the bands in this system is explained.