Molecular Reorientation as a Stochastic Process

Repeating this procedure allows to be obtained. Thus 

Many physical phenomena may be described by a second-order process or the so-called Markov process. For convenience, the time instants are ordered in the sense that 2 n- Now the conditional probability function, /(xi,ti X2,t2) is defined as the probability density that X has the value X2 at time t2 given that it had the value xi at time ti. Hence, the values taken by X at two diflFerent times are correlated in a Markov process. The distribution functions are given by (n 1) 

for a stationary Markovian process, the following is obtained  

Furthermore, when the system attains an equihbrium state, 

Finally, it may be shown [7.13] that the conditional probability for a stationary Markov process is subject to the Smoluchowski-Chapman-Kolmogorov 

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Molecular Reorientation as a Stochastic Process 179 In terms of Rs Cl, Q), the master equation becomes... 

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