Unified Approximation for the Velocity Autocorrelation Function and the Structure Function of a Simple Liquid
Abstract
A theory of oneparticle and twoparticle motions in monatomic classical liquids, which employs the twoparticle positiondependent Green's function in a fundamental way is developed. An equation of motion for the autocorrelation function is derived by assuming that a Brownian particle diffuses in a meantimedependent field. The motion of the atoms which generate the timedependent field is described by the Green's function. In addition, the Green's function is directly related to the Van Hove scattering function in a simple way. The velocity autocorrelation function and neutron scattering cross sections are computed for liquid argon by assuming a relaxation approximation for the twoparticle Green's function. Comparisons are made with recent experimental results.
 Publication:

Physical Review
 Pub Date:
 December 1968
 DOI:
 10.1103/PhysRev.176.239
 Bibcode:
 1968PhRv..176..239G