Improved q-deformed Scarf II oscillator

In this work, the improved q-deformed Scarf II oscillator (IQSO) is formulated through the Varshni conditions for diatomic molecule potential. Equation for bound state energy eigenvalues of the IQSO is obtained by the SUSYQM method, a Pekeris-like approximation scheme is used to model the centrifugal term of the Schrodinger equation. Expressions for molar entropy and Gibbs free energy are deduced for the IQSO from equations of energy eigenvalues and partition function within the context of Poisson summation formula. The IQSO is used to model experimental Rydberg-Klein-Rees (RKR) data of six diatomic molecules including: KRb (B (1)pi), CO+ (X (2)sigma(+)), Cl-2 (X (1)sigma(g) (+)), ICl (X (1)sigma(g) (+)), NbO (X (1)sigma(+)), and K-2 (X (1)sigma(g) (+)). The average absolute deviation and mean absolute percentage deviation are used as accuracy indicators. Computed data revealed that the IQSO is an excellent model in fitting the RKR data of the diatomic molecules examined in this work. Numerical values of molar entropy and Gibbs free energy calculated for ICl (X (1)sigma(g) (+)) molecule are almost indistinguishable from existing experimental data for gaseous ICl (X (1)sigma(g) (+)) molecules. This suggests that the IQSO is a near perfect model for representing the internal vibrations of the ICl (X (1)sigma(g) (+)) molecule.