ION-PAIR AND RYDBERG STATES OF ARH

Ab initio MRD-CI calculations have been carried out on electronic stat es of ArH at intermediate and large internuclear distances, where ion- pair, Ar+H-, states as well as excited Ar(P-3,P-1) states interact wit h the states involving excited H limits. The results show that charge transfer character contributes to the lowest three (2) Sigma(+) states and two (2) Pi states for internuclear distances from 4.0 to 10.0 a(0 ). The ion-pair states are found to have minima at 4.5 a(0) and at 6.5 a(0) where they correspond to the lowest (2) Pi and the first excited (2) Sigma(+) states of ArH. In addition to the above, potential energ y curves have been produced for a large number of Rydberg states of Ar H, correlating with dissociation limits up to H n = 4.