Neutron scattering study of liquid helium. Analysis of new data

A new analysis of neutron scattering data obtained earlier for liquid He-4 is presented. The experiments were made on the time-of-flight spectrometer DIN-2P1 in the pulsed reactor IBR-2 The results are analyzed by using a consistent data processing technique including the representation of the dynamic structural factor S(Q,omega) with a constant wave vector e. The one-phonon component of S(Q,omega) is approximated by using the damped harmonic oscillator function taking into account the instrumental resolution. It is shown that the experimental values of S(Q,omega) are in good agreement with the fitting model, i.e., have a simple one-component structure. The presented results indicate a peculiarity in the temperature dependence of S(Q,omega) for liquid helium in the wave vector region 0.5-0.8 Angstrom(-1). Various explanations of such a peculiarity are discussed. (C) 1997 American Institute of Physics.