Calculated long-range potential-energy curves for the 23 molecular states of I2

Abstract

The interaction energy is calculated for the 23 molecular states of I₂ as a sum of the quadrupolar electrostatic and dispersion energy terms in the multipole expansion for values of the internuclear separation R larger than 7 Å. For each state the potential energy curve and the multipolar expansion coefficients C₅ and C₆ are displayed. Results in fair agreement with experimental potential energy curves are obtained for the X O⁺_g and the B O⁺_u states. The relative importance of electrostatic and dispersion energy terms is quoted, as well as the attractive or repulsive feature of each state. The determination of the wave functions is also considered.