TWO PARTICLE VERSUS THREE PARTICLE CONTRIBUTIONS TO A DYNAMICAL CORRELATION FUNCTION IN LIQUIDS

That part of nuclear spin relaxation rate in a liquid which is caused by electric interaction with neighbour particles, RQ, is determined by the sum of a two particle and a three particle correlation function. In order to explain the weak temperature dependence generally found in pure liquid metals, we present and discuss a simple model description for the time development of the first neighbour shell. Two- and three-particle terms cancel in liquid metals for intermediate and long times, leading to a short correlation time. This is in agreement with the general trend of RQ data and with recent thorough theoretical treatments of a particular case