Analytical potential energy functions for some interhalogen diatomic electronic states

The studies of vibrational energies and analytical potential energy functions (APEFs) have been carried out for four interhalogen diatomic electronic states B(3Π0 +) and A(3Π1) of ClF, A′(3Π2u) of Cl2, and the ground state X1 Σg+ of Br2 by using an improved variational algebraic energy-consistent method (VAECM(4)). The full vibrational energies, the vibrational spectroscopic constants, the force constants fn, and the expansion coefficients an of the ECM (energy-consistent method) potential are tabulated. The VAECM(4) APEF with adjustable variational parameter λ for each electronic state is determined, and is shown to be in excellent agreement with available experimental data and has no any artificial barrier in all the calculation ranges that may appear in some other analytical potentials.