Temperature dependence of S(Q, Ω) for liquid 4HE at high pressure

Abstract

The results of a detailed neutron scattering study of the temperature dependence of S(Q, ३) for liquid 4He at 20 bars are presented. As was observed in an earlier study at saturated vapour pressure (SVP), it is found that there is a qualitative change in the character of S(Q, ३) on passing through Tॕ and that one-phonon excitations are unique to the superfluid phase. The results are analysed in terms of the Woods-Svensson model, which does not give as good a description as at SVP, and one-phonon intensities, frequencies and intrinsic widths are extracted. © 1987 The Japan Society of Applied Physics.