Comparison of empirical closed-form functions for fitting diatomic interaction potentials of ground state first- and second-row diatomics

Molecular energies of the improved Rosen−Morse potential energy model

“…The wellknown Rosen−Morse potential has been widely used to investigate the properties of diatomic molecules. [21][22][23][24][25] The drawback to the original form (eq. 1) of the Rosen−Morse potential is that the parameters appearing in the original Rosen−Morse potential lack clear physical definitions.…”

Improved expressions for the Schiöberg potential energy models for diatomic molecules

“…We adopt the expressions given by Royappa et al [37] for the Morse potential [3], Varshni potential [9], and Sage potential [11]. These three potential function expressions and expressions of parameter a are also listed in Table 1.…”

Elementary isotope effects – Sensitivity to potential energy shape

“…The harmonic potential function was chosen as the simplest and because it is the foundation of the HA. The Morse potential is the most commonly used function with two parameters (excluding bond length as not relevant to the present research) and turns out to be also on average the most exact twoparameter function for common diatomic molecules [10]. Note that E-mail address: mabuch@wmf.univ.szczecin.pl some molecules, like F 2 , display steep non-Morse-type PEC as well as a small maximum towards dissociation limit [11]; fortunately at the energies typical for equilibrium phenomena they still can be approximated correctly by the simple PECs.…”

“…Note that E-mail address: mabuch@wmf.univ.szczecin.pl some molecules, like F 2 , display steep non-Morse-type PEC as well as a small maximum towards dissociation limit [11]; fortunately at the energies typical for equilibrium phenomena they still can be approximated correctly by the simple PECs. The Wei-Hua PEC possess one parameter more which allows a desired flexibility of shape and is also on average the most exact in its class [10]. Additional advantage of the Wei-Hua PEC is the possibility to measure deviations from the Morse potential since its free parameter can be set to reduce the Wei-Hua to the Morse function.…”