An ab Initio Study ofthe E 3ΠgState of the Iodine Molecule.

The E 3Πgstate of the iodinemolecule is studied by ab initio multireference methods coupled witheffective core potentials and large basis sets. Two potential minimaare found, a global featuring an ion-pair character, and a local presentinga purely Rydberg nature. Four avoided crossings along the dissociationcoordinate attribute an interesting topology to its potential energycurve, and their effect on the vibrational levels of I2is discussed. [ABSTRACT FROM AUTHOR]