Long-range interactions in xenon

The small-k behavior of the static structure factor S(k) in a noble gas fluid is related to the two- and three-body part of the long-range interatomic potential, the London and Axilrod-Teller interaction, respec- tively. We have measured the S(k) of xenon at room temperature and four low densities by means of a small angle neutron diffractometer. A careful data analysis has allowed the determination of the strength of the long-range pair potential as well as the clear detection of the three-body effect, whose intensity has been directly obtained.