  We modify the mesonic wavefunction by using a short distance scale r0 in
analogy with Hydrogen atom and estimate the values of masses and decay
constants of the open flavour charm mesons D, Ds and Bc within the framework of
a QCD Potential Model. We also calculate leptonic decay widths of these mesons
to study branching ratios and life time. The results are in good agreement with
experimental and other theoretical values.
