Theoretical investigation about the possible consequence of artificial discontinuity in pair potential function on overall phase behavior.

摘要: On the basis of a traditional hard sphere square well (HSSW) model, we first test performance recently proposed thermodynamic perturbation theory (TPT) originating from coupling parameter expansion. It is concluded that (1) expansion-TPT predicts second-order term expansion far more accurately than several previous approximations including well-known macroscopic compressibility approximation; (2) fifth-order TPT generally little accurate third-order TPT. Next, global phase diagrams HSSW model with representative potential range values are calculated by for fluid combined first-order solid phase, and found in satisfactory agreement those as available computer simulation. Once more, theoretically compute critical curve, isostructural triple curve function an additional core attractive Yukawa (HCAY) respectively. these lines gauging outlines display abnormity compared HCAY model; particularly huge case always related to participation phase. We explain originates combination discontinuity SW tail highly discrete situation particles The present investigation eliminates possibility feasible real fluids; opportunity perhaps narrowed sample testing theories harshly.