The electron affinity of phenanthrene.

Phenanthrene is studied by photodetachment-photoelectron spectroscopy. Due to the absence of a parent ion peak in the anion mass spectrum the electron affinity could not be determined directly. However, this absence is the first indication that this molecule has a negative electron affinity. The first three water complexes of phenanthrene were studied, supplying insights into its microsolvation property. Moreover, the electron affinity of the bare molecule could be determined to be -0.01+/-0.04 eV by an extrapolation method using the water cluster data. The experimental work is supported by ab initio calculations for determining the structure of the water complexes. Finally a correlation between the electron affinity and the reduction potential of polycyclic aromatic hydrocarbons is investigated.