系综分布和涨落的准热力学理论及小涨落近似

Ensemble Distribution Quasi-Thermodynamical Theory of Fluctuation and Small Fluctuation Approximation

通常都认为涨落分布公式W∞exp(-△E-T△S+P△V/KT)只有依据涨落的准热力学理论才能得到,其实不然,实际上它和T-P系综分布是可以互相推导的,不论是从W∞exp(-△E-T△S+P△V/KT),还是T-P系综出发,利用准热力学理论都可求出各有关热力学量的涨落,而且求得的结果是彼此相等的.

It is usually supposed that fluctuation distribution formula W∝exp(-(△E-T△S+P△V)/KT) can be derived only from quasi-thermodynamical theory of fluctuation. But it is not true. In fact,the fluctuation distribution formula and T-P ensemble can be drived from each other. Using quasi-thermodynamical theory, whether from W∝exp(-(△E-T△S+P△V)/KT) or from T-P ensemble,we can get the fluctuation of relevant thermodynamical quantities, and the results by both methods are same.