Adiabatic hyperspherical study of weakly bound helium–helium–alkali-metal triatomic systems

Abstract

{sup 4}He{sub 2}-alkali-metal triatomic molecular systems are studied using the adiabatic hyperspherical representation. By adopting the best pairwise He-He and He-X interaction potentials, we search for weakly bound states of {sup 4}He{sub 2}X systems with X={sup 6}Li, {sup 7}Li, {sup 23}Na, {sup 39}K, {sup 40}K, {sup 41}K, {sup 85}Rb, {sup 87}Rb, and {sup 133}Cs. We consider not only zero total angular momentum J=0 states, but also J>0 states. We find that the {sup 4}He{sub 2}{sup 6}Li and {sup 4}He{sub 2}{sup 7}Li systems each possess two bound states with J{sup {Pi}=}0{sup +} symmetry and none with J>0, while the other {sup 4}He{sub 2}-alkali-metal species are found to support one 0{sup +} and one 1{sup -} bound state. We calculate the bound-state energies of these molecular species and discuss the essential features of the wave functions associated with these bound states.