Extended improved multiparameter exponential‐type potential energy function for diatomic molecules

Based on the improved multiparameter exponential‐type potential (IMPET), an extended IMPET (EIMPET) potential has been suggested to reduce the discrepancy between the calculated and experimental values, improving the accuracy near the equilibrium and in the asymptotic region. The average fitting deviation δ av and Root‐Mean‐Square (RMS) error is used to evaluate the performance of the potential which generates potential energy curves (PECs) and vibrational energy levels for ClF‐A( 3 Π 1 ), CP‐X 2 Σ + , ICl‐X 1 Σ + , IBr‐X 1 Σ + , CO‐X 1 Σ + , and 6 Li 2 ‐X 1 Σ + molecules that agree better with the Rydberg‐Klein‐Rees (RKR) data than Morse, Huxley‐Murrell (HM) and IMPET potentials. This work provides a reference for the construction and improvement of potential energy functions for diatomic molecules.