Viscosity for Isotopes of Helium with HCB Model

The calculation of viscosities for the fluids of Helium isotopes, He³ and He⁴, has been made by using HCB models. The phase shifts required for its calculation of viscosities have been obtained by numerical integration of the radial wave equation expressed by taking a simple form of Leenard-Jones intermolecular potential specified in terms of the support function h(x) and surface to surface coordinate representation K. For both He³ and He⁴ the phase shifts resemble the rigid sphere behavior for high collision energies of the two colliding helium molecules of the same species. The cross-sections required for the calculation of viscosities below temperature 5K for the fluids of helium isotopes has also been discussed.