Pseudopotential study of some prominent band systems of the spectra of the I2 molecule

Using pseudopotential multiconfiguration self-consistent field (MCSCF) techniques several states of the I2 molecule are studied to explain some important band systems of the spectra of iodine vapor. Spectroscopic parameters of the states X 1Σg+, D 1Σg+, B 3Π0 +u, Π1u3, Π2u3, Π03 +g, Π1g3, Π2g3 are evaluated and compared with known experimental data. Attempts are made to resolve questions in regard to the assignments of molecular states to the above band systems as well as those pertaining to the position and symmetries of various curves that have remained only partially answered over the years.