Ro-vibrational energy and thermodynamic properties of molecules subjected to Deng-Fan potential through an improved approximation

Abstract

Accurate solution of the Schrödinger equation with Deng-Fan potential is presented by means of Nikiforov-Uvarov method. A modified Pekeris-type approximation is proposed for the centrifugal term, from a linear combination of the $r\to 0$ and $r\to r_e$ limits. It can potentially offer a series of approximations (depending on an adjustable parameter $\lambda$). The existing approximations in the literature can then be recovered in certain special cases. Its efficiency and feasibility is demonstrated by a critical comparison of eigenvalues produced at various $\lambda$'s for four molecules, \emph{viz.}, H${}_2$, LiH, HCl and CO. Analytical expressions are derived for energies, eigenfunctions and the thermodynamic properties such as vibrational mean free energy, vibrational free energy, vibrational entropy and vibrational specific heat. The effect of quantum correction on partition function and thermodynamic properties is discussed by including the correction up to 10th-order, for H${}_2$ and LiH. The effect of $\lambda$ parameter on these properties is also studied.

21 pages, 6 figures, 1 table

References in corpus (5)

• Equivalence of the empirical shifted Deng-Fan oscillator potential for diatomic molecules
• On the ro-vibrational energies for the lithium dimer; maximum-possible rotational levels
• Studies on bound-state spectra of Manning-Rosen potential
• The Rotation-Vibration Spectrum of Diatomic Molecules with the Tietz-Hua Rotating oscillator
• Energy states of some diatomic molecules: Exact quantization rule approach

Cited by in corpus (2)

• Analytical solution of $D$ dimensional Schrödinger equation for Eckart potential with a new improved approximation in centrifugal term
• Ro-vibrational energy analysis of Manning-Rosen and Pöschl-Teller potentials with a new improved approximation in the centrifugal term