Calculations of long-range three-body interactions forLi(2S2)−Li(2S2

Abstract

General formulas for calculating the several leading long-range interactions among three identical atoms where two atoms are in identical S states and the other atom is in a P state are obtained using perturbation theory for the energies up to second order. The first order (dipolar) interactions depend on the geometrical configurations of the three atoms. In second order, additive and nonadditive dispersion interactions are obtained. The nonadditive interactions depend on the geometrical configurations in marked contrast to the case where all three atoms are in identical S states, for which the nonadditive (also known as triple-dipole or as Axilrod-Muto-Teller) dispersion interactions appear at the third order. The formalism is demonstrated by the calculation of the coefficients for the Li(2 2 S)-Li(2 2 S)-Li(2 2 P) system using variationally-generated atomic lithium wave functions in Hylleraas coordinates. The present dipolar coefficients and additive and nonadditive dispersion coefficients may be useful in constructing precise potential energy surfaces for this three lithium atom system.

Calculations of long-range three-body interactions for He( n0λS )-He( n0λS )-He( Yan1, Tang2, Yan3 et al. 2018Phys. Rev. ASelf Cite5041View full textAdd to dashboardCite

“…According to the perturbation theory, the first-order energy correction for the He(n 0 λ S)-He(n 0 λ S)-He(n 0 λ P ) system is ∆E (1)…”

“…The nonadditive terms may also not be neglected in constructing a three-body potential surface for He(n 0 λ S)-He(n 0 λ S)-He(n 0 λ P ). The curves of potential energy (E) of the He(1 1 S)-He(1 1 S)-He(2 1 P ), He(2 1 S)-He(2 1 S)-He(2 1 P ) and He(2 3 S)-He(2 3 S)-He(2 3 P ) systems, resulting from ∆E (1) and ∆E (2) for this geometrical structure, are shown in Figs. 5 - Fig.…”

“…He 6465.31 (6) 6465.31 (6) 6465.31 (6) 1278.7588 (1) 1278.7588 (1) 1278.7588(1) (1, M = ±1) 3.003980860078 12.220082977532 13.003980860078(1) 7501.37 (5) 5945.01 (7) 1354.73975890 (6) 1354.73975890 (6) 1001.21632520(4) 5946.44 (6) 1355.00602327 (7) 1355.00602327 (7) 1001.41310708(5)…”

“…1: Long-range potentials for the He(1 1 S)-He(1 1 S)-He(2 1 S) system for three different types of the zeroth-order wave functions, where the three atoms form an equilateral triangle, in atomic units. For each curve labeled by a wave function, the plotted curve is the sum of ∆E (1) and ∆E (2) , where ∆E (1) =0.…”

“…We recently demonstrated for the case of three Li atoms with two atoms in their ground states and one atom in the first excited P state that their long-range (i.e. atoms sufficiently separated that electron exchange is negligible) interactions exhibit a first order interaction potential dependent on the geometrical configuration of the atoms and that in second order additive and non-additive dispersion interactions appear [1] (subsequently referred to as Paper I). These long-range interactions are in sharp contrast to the case of three ground state atoms, where geometric-configuration non-additive dispersion interactions (sometimes called Axilrod-Teller-Muto terms) appear in third order, cf.…”