Deep inelastic atomic scattering of x rays in liquid neon

An inelastic x-ray scattering (IXS) experiment in liquid neon has been performed in the +/-100 meV exchanged energy range and at exchanged wave numbers, q, comprised between 1 and 16 A(-1). At the highest probed q's a deep inelastic scattering regime is reached where the Ne core electrons, after collision with the x rays, recoil almost freely with an effective mass equal to the Ne atomic mass. IXS in this high q regime is here shown to provide quantitative information on the atomic momentum distribution of liquid Ne, thus supplying a complementary technique to neutron scattering. There are several open problems in quantum and classical liquids which can benefit from this complementarity.