Oscillations and line shapes ofS(Q, ω)in quantum fluids

B. Tanatar, E. F. Talbot, H. R. Glyde
1987 Physical Review B (Condensed Matter)  
The dynamic form factor S(Q, cv) of the quantum liquids 3He and 4He is evaluated in the range 3~Q~10 A ' within the random-phase approximation (RPA) beginning from the He-He pair potential. In He, the width W(Q) of S(Q, cv) is found to oscillate with Q as observed. These oscillations originate in the He-He interaction in the RPA In H W(Q) n e,~agrees in magnitude with experiment but does not oscillate. This suggests W(Q) is not simply related to the total He-He scatter'ing cross section a(Q).
more » ... e calculated S(Q, cv) has high-frequency tails which make the kinetic energy greater than expected from W(Q) and a Gaussian S(Q, cv).
doi:10.1103/physrevb.36.2425 pmid:9943120 fatcat:2pzkt6r5bfbt7okbpbbfqze73u