EFFICIENT CALCULATION OF THE INTRAMOLECULAR CONTRIBUTION TO ORIENTATIONAL AUTOCORRELATION FUNCTIONS USING DYNAMIC ROTATIONAL ISOMERIC STATE THEORY

A matrix formulation of the time-dependent transition partition function is combined with a generator matrix formalism to permit rapid and accurate calculation of the first and second orientation autocorrelation functions, m(0)-m(r)) and {(3/2)(m(0)-m(r))2 - 1/2), for a chain molecule. Here m is a unit vector rigidly attached to a bond in the chain, and 0 and r denote this vector at times 0 and r. The time-dependent a priori probabilities of the type p*(x\xo), which denotes the probability that a bond i in state x at time 0 is still in state x at time r, reduce correctly to those obtained from conventional equilibrium rotational isomeric state theory at zero and infinite times. © 1990, American Chemical Society. All rights reserved.