The force of cohesion and a new equation of internal energy in the condensed phase are exploited to obtain the intermolecular energies of different fluids in the gaseous and liquid states for polar and nonpolar molecules The am active energies of dispersion. orientation, and induction are expressed in the form of a unique and general relationship taking into account only the polarizability alpha, the dipole moment beta, and the excluded volume V(tau) of the molecule under consideration It thus becomes possible to calculate the critical temperature on the basis of these three molecular parameters