title: Photodesorption of excited iodine atoms from KI (100).
abstract: Band-to-band photoexcitation of potassium iodide single crystals with UV photons produces thermal and hyperthermal I-atom emission in both the ground I((2)P(3/2)) and spin-orbit excited I( *)((2)P(1/2)) states. Thermal halogen atom emission is preceded by H-center diffusion from bulk to surface and excited atom emission indicates that the excited hole spin state relaxation is incomplete before H-center diffusion to the surface. The hyperthermal I-atom kinetic energy distribution is inverted in the sense that the electronically excited I( *)((2)P(1/2)) atoms are more energetic than the ground state I((2)P(3/2)) atoms. The mechanism for hyperthermal emission of halogen atoms and their kinetic energy distributions are discussed in terms of recent calculations and a simple curve crossing model for the dynamical desorption process.
authors.affiliation: Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA.
authors.forename: Alan G
authors.initials: AG
authors.lastname: Joly
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Beck
authors.forename: Wayne P
authors.initials: WP
authors.lastname: Hess