Analytical formulas for long-range energies of the 16 Ωg,u(+/-) states of alkali dimers dissociating into M(ns)+M(np 2PJ)

Analytical formulas for long-range energies of the 16 Omega(g,u)((+/-)) states of alkali dimers dissociating into M(ns) + M(np P-2(J)) are displayed in terms of the long-range C-n coefficients for the 2(S+1)Lambda(g,u)((+)) corresponding stales, and including exchange interaction energy contributions. Corrections due to retardation effects fur resonant-dipole interactions are also included. For values of the internuclear distance IZ large enough so that only Coulombic interactions in R-3 are nonnegligible, the variation with R of the long-range energy is seen to be different rent the usually assumed C-3/R-3 form. Present formulas can be used both to predict accurately long-range energies and to fit experimental energies now available in such long-range of R from photoassociative spectroscopy. As an example, they have been used, together with more accurate values of C-n coefficients than those used some 10 years ago, to predict again tie three states of Rb-2 displaying structures (well and barrier) at long range, i.e., O-g(-)(3/2), 1(u)(3/2). and 1(u)(1/2). (C) 1998 Academic Press.