V. Spirko et al., Adiabatic energies and perturbative non-adiabatic corrections for Coulombic three-particle systems in the hyperspherical harmonics formalism, J PHYS B, 32(2), 1999, pp. 429-441
Citations number
29
Categorie Soggetti
Physics
Journal title
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
The adiabatic energies and non-adiabatic corrections of the bound and lowes
t-lying quasi-bound S states of the light Coulombic three-particle systems,
the negative positronium Ps(-) and muonium Mu(-) ions and the neutral He(1
s(2)) atom, are evaluated using the hyperspherical harmonics formalism. The
calculations are based on the adiabatic separation of the hyperradial and
the hyperangular degrees of freedom. The non-adiabatic corrections are dete
rmined using high-order Rayleigh-Schrodinger perturbation theory. Although
the adiabatic perturbation series do not always converge, they can be accur
ately summed for isolated states applying Wynn's epsilon algorithm. The per
turbation treatment exhibits high numerical stability with respect to the n
umber of basis functions and it is therefore possible to perform these calc
ulations employing very large basis set expansions. The perturbation series
pertaining to the well-isolated ground states are summable even in the dia
batic representation.