The slope and curvature of Isgur Wise function for Bc meson is computed
in a QCD potential model in two different approaches of choosing the
perturbative term of the Cornell potential. Based on heavy quark effective
theory the exclusive semileptonic decay rates of Bc meson into the $c\bar c\
(\eta_c,J/\psi)statesareexploited.SpinsymmetrybreakingeffectsareignoreduptoaparticularpointandtheformfactorsareconnectedwithIsgur−Wisefunctionforotherkinematicpointsincetherecoilmomentumofc\bar cfromB_{c}$ is small due to its heavy mass.Comment: 13 pages, 4 tables, 4 figures,Accepted to Int.J.Mod.Phys.