Potential energy curve of the X0+(1Σ++) ground state of HgAr determined from A0+(3Π) → X0+ and B1(3Σ+ → X0+ fluorescence spectr

A0+(3Π) → X0+(1Σ+) and B1(3Σ+) → X0+(1Σ+) fluorescence spectra of HgAr van der Waals molecules were previously produced in a pulsed supersonic molecular beam crossed with a pulsed dye-laser beam, following excitation of single vibronic levels. The dispersed fluorescence displayed characteristic Condon internal diffraction (CID) patterns consisting of bound-free reflection type, continuous spectra, and also bound-bound discrete features. An analysis of the AO+ → X0+ and B1 → XO+ bound-bound spectra indicates that a Morese function is an adequate representatation of the X0+ potential energy (PE) curve below the dissociation limit. In simulation of the AO+ → X0+ bound-free spectra of the Morse, Lennard-Jones (n − 6) and Maitland-Smith functions were tested, and the Maitland-Smith potential was found to be a good representation of the repulsive wall of the X0+ PE curve above the dissociation limit over the internuclear separation range R = 2.8–3.5 Å.