  Our present studies has shown that the mass dependence of EVF show mass
asymmetry independent behaviour. This is due the fact that with increase in
asymmetry, the number of nucleon-nucleon collisions and repulsive Coulomb
interactions decreases, therefore EVF increases. The increase in EVF with
asymmetry is more for lighter nuclei as compared to heavier nuclei due to the
further less magnitude of Coulomb repulsions in lighter nuclei as compared to
heavier ones.
