Ro‐vibrational energy and thermodynamic properties of molecules subjected to <scp>Deng–Fan</scp> potential through an improved approximation

Accurate solution of the Schrödinger equation with Deng–Fan potential is presented by means Nikiforov–Uvarov method. A modified Pekeris-type approximation proposed for centrifugal term, from a linear combination r → 0 and re limits. It can potentially offer series approximations (depending on an adjustable parameter λ). The existing in literature then be recovered certain special cases. Its efficiency feasibility demonstrated critical comparison eigenvalues produced at various λ's four molecules, namely, H2, LiH, HCl CO. Analytical expressions are derived energies, eigenfunctions thermodynamic properties such as vibrational mean free energy, entropy specific heat. effect quantum correction partition function discussed including up to 10th-order, H2 LiH. λ these also studied.