METHODS OF EVALUATION OF 2ND GRUNEISEN CONSTANT AND ANDERSON-GRUNEISEN CONSTANT

The second Gruneisen constant Q = [partial derivative 1n gamma(g)/part ial derivative 1n V](T) and Anderson-Gruneisen constant delta(T)[=(1/a lpha K-T)partial derivative K-T/partial derivative T](P) have been the subject of various investigations. In this paper we calculate gamma(g )' = (partial derivative gamma(g)/partial derivative P)(T),c(1)' = (pa rtial derivative c(1)/partial derivative P) = {partial derivative/part ial derivative P(partial derivative K-T/partial derivative P)}(T), Q a nd delta(T) for Cd, As2S3 and C-60 Thurston's method, the Delanoy Cout ris method, Bardeen's potential function and the Girifalco potential f unction (GPF) to derive these properties. Four methods have been appli ed for Cd in the evaluation of gamma(g)'. The results obtained by thre e methods agree very well, while that from the fourth method is found to give a higher value. A relation between gamma(g)' and Q has been de rived. We also compute these properties for As2S3 and C-60. In this co nnection, we point out that the present methods give reasonably good v alues consistent with each other. It is interesting to note that gamma (g)(th) obtained via the GPF scheme and that given by White et al [29] are in close agreement with each other and therefore used in the eval uation of Q. We used the value of White et al. for gamma(g)(th) (exter nal). (C) 1997 Elsevier Science Ltd.