Gc. Hegerfeldt et T. Kohler, How to study the elusive Efimov state of the He-4(3) molecule through a new atom-optical state-selection technique, PHYS REV L, 84(15), 2000, pp. 3215-3219
Excited states and excitation energies of weakly bound systems, e.g., atomi
c few-body systems and clusters, are difficult to study experimentally. For
this purpose we propose a new and very general atom-optical method which i
s based on inelastic diffraction from transmission gratings. The technique
is applicable to the recently found helium trimer molecule He-4(3), allowin
g for the first time an investigation of the possible existence of an excit
ed trimer state and determination of its excitation energy. This would be o
f fundamental importance for the famous Efimov effect.