OBSERVATION OF THE DIPOLE-BOUND EXCITED-STATE OF THE I-CENTER-DOT-ACETONE ION-MOLECULE COMPLEX

Photofragmentation action spectra of the I- .acetone ion-molecule complex reveal the existence of an excited state, located just below the electron detachment threshold, which is thought to correspond to a dipole-bound state derived primarily from the electric dipole moment of acetone. The excited state relaxes by fragmentation into the acetone anion, a dipole-bound ground state anion. This type of excited state should be a general property of ion-molecule complexes, X- .M, where M has a significant dipole moment and X does not, and is a microscopic precursor of the charge transfer to solvent bands observed for anions in dipolar solvents. © 1995 American Institute of Physics.