No abstract

A modified form of 2CLJDQP potential model is proposed to calculate the second virial coefficients of two-center Lennard-Jones molecules. In the presented potential model, the potential parameters σ and ε are considered as the temperature-dependent parameters in the form of hyperbolical temperature function based on the theory of temperaturedependent potential parameters. With this modified model, the second virial coefficients of some homonuclear molecules (such as O 2 , Cl 2 , CH 3 CH 3 , and CF 3 CF 3 ) and heteronuclear molecules (such as CO, NO, CH 3 F, CH 3 Cl, CH 3 CF 3 , CH 3 CHF 2 , and CF 3 CH 2 F) are calculated. Then the Lorentz-Berthelot mixing rule is modified with a temperaturedependent expression, and the second virial coefficients of the heteronuclear molecules (such as CH 3 F, CH 3 Cl, and CH 3 CF 3 ) are calculated. Moreover, CO 2 and N 2 O are also studied with the modified 3CLJDQP model. The calculated results from the modified 2CLJDQP model accord better with the experimental data than those from the original model. It is shown that the presented model improves the positive deviation in low temperature range and negative deviation in high temperature range. So the modified 2CLJDQP potential model with the temperature-dependent parameters can be employed satisfactorily in large temperature range.