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

Exactly solvable reference potentials of several smoothly joined Morse-type components were constructed for the lowest two excimer states of the Ar(2) 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 (r >= 1.9 angstrom). A large number of quantum mechanical Franck-Condon factors for the 0(u)(+) --> 0(g)(+) and 1(u) --> 0(g)(+) 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 Ar(2)(*) 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 (1988 J. Chem. Phys. 89 4535) have been confirmed. The calculated spectroscopic parameters, omega(e) = 296.26 cm(-1), D(e) = 6128.3 cm(-1) for the 0(u)(+) state and omega(e) = 287.30 cm(-1), D(e) = 5929.6 cm(-1) for the 1(u) state, are consistent with previous estimations. Separation between the minima of the potential wells at R(e) = 2.3893 angstrom was found to be 416.1 cm(-1) (51.59 meV), compared with 606.8 cm(-1) (75.24 meV) splitting in the separated-atom limit.