Photoelectron Spectroscopy of 4-Bromochlorobenzene Dimer and Trimer Anions

摘要

Clusters are the aggregates of molecules or ions which have intrinsic properties that are not found in their monomer unit. Their structure and charge distribution greatly affect the properties of the clusters. Charge resonance is the key factor that determines the structure of the cation clusters of aromatic hydrocarbons. T. Shida and S. Iwata also calculated the charge resonance band and observed it experimentally, With advances in molecular beam apparatus and quantum calculations, anion clusters have been extensively studied. Benzene does not form a stable dimer anion in the gas phase, and naphthalene forms a dimer anion which may have T-shaped geometry due to the strong repulsion from the π-electron. Dimer anions larger than naphthalene all have parallel-displaced (PD) geometries with charge resonance. Sometimes homocluster anions show ion core switching with the increase of the cluster size.