Models for low-temperature helium dimers and trimers

摘要

We have shown that a simle model based on pairwise deltafunction potentials can,with an appropriate choice of parameters,represent the general behavior of ultra-low temperature helium dimers and trimers,including allpossible isotopomers.The species ~4He_2,~4He_3,and ~4He_2~3He are stable,with binding energies of approximately 1.3,100,and 10 mK,respectively.An Efimov state for ~4He_2~3He is also predicted,bound by 2.4mK.The remaining dimers and trimers,~4He~3He,~3He_2,~4He_2,~4He~3He_2,and ~3He_3,are evidently unstable.