Electronic Excitation and Thermal Effects in Alkali-Halide Cluster Anions

Abstract

We have observed electronically excited states in alkali-halide cluster anions with one excess electron. Using photoelectron spectroscopy, we have found two narrow states in (KI)-2, (NaI)-2, and (NaCl)-2, consistent with a dipole-bound electron, while larger cluster anions exhibit a single broad excited state. In the larger systems, electronic excitation is often accompanied by vibrational excitation and thus a change in cluster temperature. Such temperature changes affect cluster structure and in some cases lead to rapid thermal isomerization.

Photodesorption of Alkali Anions from Alkali-Halide Cluster Anions

“…In a previous study, on one-excess-electron AHCs, we attributed such broad absorptions to strong couplings between electronic and vibrational excitations [24] and found that those absorptions often lead to substantial heating or cooling of the clusters.…”

5 Gas-phase stabilities of small anions

“…Fatemi et al 123 used photoelectron spectroscopy to investigate the alkaline halide dimers (MX) 2 2 (M = Na, K; X = Cl, I). The spectra of these dimers show a relatively sharp single peak without notable vibrational progression, consistent with a linear C Hn chain arrangement.…”

First Evidence of Rhombic (NaCl)2‐. Ab initio Reexamination of the Sodium Chloride Dimer Anion.

“…3,14,15 Although reliable and informative, the experimental measurements cannot determine the geometrical structure of the anion or neutral species. In contrast, theoretical treatments, especially ab initio methods, are able to provide precise information about the origin of the electron binding by describing the potential responsible for it.…”