Dispersion forces and long-range electronic transition dipole moments of alkali-metal dimer excited states
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)
A formalism of degenerate perturbation theory is presented, in which the initial basis set of functions is fully adapted to the perturbation. This full adaptation is obtained by imposing a simple condition which leads to an iteration procedure free of singularities. The formalism includes as a special case nondegenerate perturbation theory. By using it we calculate the dispersion coefficients of alkali-metal dimers for molecular states which dissociate into one atom in the ground state and the other in one of the first two {ital S}, {ital P}, or {ital D} excited states. The dispersion forces are extracted from the first- and second-order energy corrections. Model potentials are used in order to describe the motion of the valence electron in the field of the alkali-metal positive-ion core. Using the first-order wave-function correction, we investigate the leading terms of the long-range expansion of the electronic transition dipole moments. An extension of the Dalgarno-Lewis method is developed in order to handle the radial matrix elements which involves a reduced Green`s function for real and complex energies. The results are compared with previous computations.
- OSTI ID:
- 76493
- Journal Information:
- Physical Review A, Vol. 52, Issue 1; Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
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