Structure of gaseous Kr in the low-q region by neutron scattering and interaction potentials

Accurate experimental information on the long-range triplet interactions in noble fluids, as well as on the two-body potential, can be obtained from the low-density behavior of the static structure factor $S\left(q\right)\mathrm{}$ in the small-q region. The results here reported of a recent low-q neutron diffraction investigation in Kr, devoted to undercritical densities in the range $2.4<n/{\mathrm{nm}}^{\mathrm{-}3}<4.3,$ provide important indications on the pair interactions and allow also a reliable analysis of irreducible three-body potential effects on the measured structure, from which the triple-dipole Axilrod-Teller strength is extracted with unprecedented accuracy.