Infrared transient absorption and electronic state of localized self-trapped excitons in KCl:I

The infrared transient absorption and electronic state of the on-center-type self-trapped exciton (STE) localized at an iodine dimer in KCl:I were investigated. The polarization properties and vibronic structure of the absorption band indicate that the electronic state of the on-center-type STE is rather extended so that the splitting of the 2p-like sublevels is very small.