  We have calculated the quantum correction(QC) in the vibrational partition
function and thermodynamic state functions, e.g., internal energy, specific
heat, free energy and entropy by using improved Manning-Rosen(MR) potential for
Li_2, Na_2 and Cs_2 dimers numerically using Mathematica. Expression for
classical partition function calculated using Poisson summation formula and a
closed expression in the form of error function is calculated. The change in
the partition function and thermodynamic properties with addition of quantum
correction are discussed in detail and then compared with their classical
counterpart.
