New empirical potential energy function for diatomic molecules

Abstract

A new empirical potential energy function for diatomic molecules, which has the simple form of V(r)=(arb+m)/(1−enr) is introduced, where a,b,m and n are variational parameters of the function. To obtain the parameters of this function, it was fitted to the points, which were obtained previously from the RKR calculations for a wide range of diatomic molecules in both their ground and excited states. The reliability of the proposed function was checked by calculation of some spectroscopic constants such as bond length (Re), dissociation energy (De), force constant (Ke), rotational constant (Be), vibrational frequency (ωe), anharmonicity constant (ωexe) and vibration–rotation coupling constant (αe) for these molecules. For ωexe and αe the results were compared with those of the Morse, Rosen–Morse, Rydberg, Pöschl–Teller, Linnett, Frost–Muslin, Varshni, Lippincott and Rafi functions. Our results are consistent with or have less error than those of the above-mentioned functions.