We study the structure of triatomic molecules containing two helium atoms and one alkali-metal atom X (X = Li, Na). The three-body Schr\"odinger equation is solved in hyperspherical coordinates using the He-He and He-X pair van der Waals potentials available in the literature. We calculate the structural properties of the ${\mathrm{He}}_{2}\mathrm{Li}$ and ${\mathrm{He}}_{2}\mathrm{Na}$ bound states, and analyze one-dimensional pair and angle distribution functions as well as two-dimensional pair-pair and angle-angle distribution functions. These bound states are characterized by so peculiar weakly bound structures that classifying them into particular sizes and geometrical shapes appears to be elusive. Particularly, the ${J}^{\mathrm{\ensuremath{\Pi}}}={0}^{+}$ excited states of $^{4}\mathrm{He}_{2}^{6}\mathrm{Li}$ and $^{4}\mathrm{He}_{2}^{7}\mathrm{Li}$ are found to constitute giant triatomic molecules with their size amounting to several hundred bohrs.We study the structure of triatomic molecules containing two helium atoms and one alkali-metal atom X (X = Li, Na). The three-body Schr\"odinger equation is solved in hyperspherical coordinates using the He-He and He-X pair van der Waals potentials available in the literature. We calculate the structural properties of the ${\mathrm{He}}_{2}\mathrm{Li}$ and ${\mathrm{He}}_{2}\mathrm{Na}$ bound states, and analyze one-dimensional pair and angle distribution functions as well as two-dimensional pair-pair and angle-angle distribution functions. These bound states are characterized by so peculiar weakly bound structures that classifying them into particular sizes and geometrical shapes appears to be elusive. Particularly, the ${J}^{\mathrm{\ensuremath{\Pi}}}={0}^{+}$ excited states of $^{4}\mathrm{He}_{2}^{6}\mathrm{Li}$ and $^{4}\mathrm{He}_{2}^{7}\mathrm{Li}$ are found to constitute giant triatomic molecules with their size amounting to several hundred bohrs.

Physical Review AJul 11, 201714 citations

Exotic helium dimers: a giant comes out of the cold

M. Walhout, Jérémie Léonard, Michèle Leduc

Europhysics newsMay 1, 20050 citations

{\mathrm{He}}_{2}\mathrm{Li}

and

{\mathrm{He}}_{2}\mathrm{Na}

bound states, and analyze one-dimensional pair and angle distribution functions as well as two-dimensional pair-pair and angle-angle distribution functions. These bound states are characterized by so peculiar weakly bound structures that classifying them into particular sizes and geometrical shapes appears to be elusive. Particularly, the ${J}^{\mathrm{\ensuremath{\Pi}}}={0}^{+}$ excited states of

^{4}\mathrm{He}_{2}^{6}\mathrm{Li}

and

^{4}\mathrm{He}_{2}^{7}\mathrm{Li}

are found to constitute giant triatomic molecules with their size amounting to several hundred bohrs.