This study demonstrates that the slope B' of the linear isotherm of (Z - 1)V-8.5/3 versus (1/rho)(4.5/3) for liquid cesium metal has a contribution from the noncentral part of interaction potential energy function, where Z is the liquid compressibility and V = 1/rho (where rho is the molar liquid density). First, it is shown macroscopically that B' conforms to the second virial coefficient B-2. However, it is exceedingly smaller at low temperatures and approaches close agreement at high temperatures. The substitution of B' for B-2 in the Ihm-Song-Mason statistical mechanical equation of state has led to a prediction of the liquid density of cesium metal within +/-5% in the temperature range of 300-1400 K. The fact that the Ihm-Song-Mason equation of state has been derived for nonpolar and slightly polar fluids, with the dispersive interaction potentials as their major intermolecular interaction, has led us to propose that B' is related to the interaction potential that is contributed from dispersive interaction between the Cs atoms. Although a microscopic approach, we have used the angular perturbation method in the second part and calculated the noncentral second virial coefficient (B-2(angular)). Angular distribution of the electron density is approximated by the usual multipoles of the electrostatic nature. The Gaussian 98W program at the LanL2DZ and LanL2MB levels of theory has been used to assign and determine components of the multipoles moment required for the calculation of B-2(angular). The Boltzmann factor, which comprises the pair potential function used to derive the isotherm, is applied as the energy distribution required for the calculation of B-2(angular). The results of the first and second parts of the calculations show that dispersive interaction, which can be described and approximated by the multipole expansion of the noncentral electron density of the Cs atom, contributes to B'.