MULTICHANNEL QUANTUM-DEFECT THEORY OF DOUBLE-MINIMUM 1-SIGMA-G+ STATES IN H2 .1. POTENTIAL-ENERGY CURVES

Multichannel quantum-defect theory is applied to the highly accurate 1SIGMA(g)+ ab initio excited-state potential-energy curves calculated by Wolniewicz and Dressler [J. Chem. Phys. 82, 3262 (1985); and (private communication)]. We show that the three double-minimum states, EF, GK, and HH, can be represented to within 8 cm-1 by a smooth R-dependent 3 X 3 nondiagonal quantum-defect matrix. This quantum-defect matrix corresponds to a collision of the Rydberg electron with the H-2(+)target, which may be in either the 1sigma(g) or 1sigma(u) state. Also discussed is the use of this quantum-defect matrix to calculate diabatic states, more highly excited Born-Oppenheimer states, and the electronic ionization width of the superexcited (1sigma(u))2 doubly excited state.