The interaction between excited and ground state rare gas atoms. II. Homonuclear excimers with spin–orbit coupling

A model of potential is proposed to describe the potential curves of the first excited states of rare gas homonuclear excimers [X(np6, 1So)−X(np5(n+1)s, 1,3P)]. The model is composed of three terms: the long range part of the interaction given by a partial summation of the multipole series, the short range term which is the exchange Fermi potential, and the core–core interaction deduced from the ion–atom asymptotic model of Duman and Smirnov. The spin–orbit coupling is added using the semiempirical method of Cohen and Schneider. Three adjustable parameters are introduced to obtain the best value of the O+u(3P1) and of the O+u(1P1) potential well. Comparison with ab initio potential curves is made, and also with experimental data for the Ne*2, Ar*2, Kr*2 and Xe*2 excimers.