Molecular Constants and Potential Energy Curves for Diatomic Molecules

Abstract

By using the function U = Ce^{—a(r—r_e)} — C′e^{—a′(r—r_e)} with C = 10^—12e^{—a(r_e—r₁₂)}, and taking a = 6.0 × 10⁸ cm^—1, r₁₂ values calculated from the band spectrum constants are nearly the same (1.46A) for all except highly excited states of all diatomic molecules containing only elements in the first row of the periodic table and having 12 or more electrons. This indicates that the repulsive term is nearly the same in all of these cases. This relation enables one to calculate, from experimental values of two of the molecular constants (e.g., ω_e and ω_ex_e) the magnitudes of others (e.g., r_e, B_e and α). Calculated values of ω_ey_e and ω_ez_e are invariably small but not zero. The dissociation energy is (empirically) about 0.8 (C′ — C), calculated using a = 4.0 × 10⁸ cm^—1.