Potential energy curves and transition moments for the excimer states 0u+ (3P1) and 1u (3P2) of Ar2

TL;DR

This paper develops accurate, exactly solvable potential energy curves for Ar2 excimer states, fitting experimental data to compute transition moments and Franck-Condon factors, thereby explaining observed spectroscopic features.

Contribution

It introduces reliable Morse-type reference potentials for Ar2 excimer states, fitted to experimental data, enabling precise calculation of transition moments and spectral features.

Findings

Potential energy curves reproduce emission spectra

Vibrational levels confirmed by previous studies

Transition moments match radiative lifetimes

Abstract

Exactly solvable rererence potentials of several smoothly joined Morse-type components were constructed for the lowest two excimer states of Ar2 molecule. The parameters of the potentials have been ascertained by fitting to the experimental data, and they are reliable in a wide range of nuclear separations. A large number of quantum mechanical Franck-Condon factors for bound-free and bound-bound transitions have been calculated and compared with the observed spectroscopic features. The fitting procedure also involved dipole transition moments, which have been adjusted to the known radiative lifetimes of the vibrational levels. The resulting potential energy curves accurately reproduce the first and the second emission continua of Ar2* as well as the oscillatory spectrum related to their inner turning point region. The numbering and the positions of the vibrational levels reported by Herman et al. [P. R. Herman, P. E. LaRocque, and B. P. Stoicheff, J. Chem. Phys. 89, 4535 (1988)] have been confirmed.