Accommodation of two excess electrons in sodium chloride cluster anions

Abstract

We report photoelectron spectra of sodium chloride cluster anions, (NaCl)nNa~ (n = 1-21), which contain two excess electrons. We observe three distinct types of spectra, corresponding to three different modes for accommodating the two electrons. Our evidence suggests that, in some clusters, the electrons form spin pairs that either occupy a single anion vacancy as an F' color center or localize on a Na"^ cation to form a Na~ anion. In other clusters, the two electrons separately occupy a pair of anion vacancies as a double F color center.

Probing the early stages of salt nucleation—Experimental and theoretical investigations of sodium/potassium thiocyanate cluster anions

“…30 Meanwhile, the larger spatial dimensions of alkali thiocyanate clusters could result in separations large enough for excess charges and lead to the formation of multiply charged anion (MCA) clusters, which have not been observed for alkali halide salt clusters. [9][10][11][12][13][14][15][16][17] The formation of MCAs in return could attract cations and accelerate nucleation and crystal growth. Third, alkali halide cluster anions M n X − n+1 (where M is an alkali metal atom and X is a halogen atom) have been discovered possessing electron binding energies higher than any atomic anions and have been named superhalogen anions.…”

“…Electronic mail: xuebin.wang@pnnl.gov level information of crystal nucleation and growth is still largely unknown, and most experimental studies are performed at the macro-or mesoscopic scale because there are few experimental methods which approach the atomic scale in solutions or vapors. So far, there have been few relevant experiments performed on alkali halide clusters in the gas phase, produced by laser ablation on solid salt samples; these studies employed mass spectrometry, ion mobility measurements, and photodetachment photoelectron spectroscopy [9][10][11][12][13][14][15][16][17] and have provided very useful information about structural evolution in the early growth stage of alkali halide salts. Compared to experiments, molecular dynamics and Monte Carlo simulations have been developed and used for decades to study nucleation, and a large number of studies have been carried out using computer simulations.…”

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

“…Substantial current interest in binding an excess electron to ionic clusters produced a significant number of manuscripts devoted to such phenomenon over the past two decades. [1][2][3][4][5][6][7][8][9][10] The study of such clusters can provide valuable information about the connection between the properties of the isolated atoms, molecules, or ions and those of the bulk material. In addition, clusters with excess electrons exhibit diverse electron binding motifs, especially as the cluster sizes increase.…”

Dissociation pathways and binding energies of (LiH)nLi+ and (LiH)nLi+3 clusters

“…Finally, referring to the rough ionic model used for MX alkali halide clusters, the most pertinent question is how the charge corresponding to the two excess electrons is distributed. Recently, Xia and Bloomfield 35 have studied this problem in negatively charged ͑NaCl͒ n Na Ϫ clusters. The excess electrons tend to be localized on anion vacancies or on a Na ϩ cation ͑to form a Na Ϫ anion͒.…”