Electron binding energies and the fundamental gap of a push-pull dye in a polar environment: p-nitroaniline in liquid water

Abstract

The outer valence electron binding energies and the fundamental gap of p-nitroaniline (PNA) in water were determined by electron propagator theory. The adopted methodology relies on the calculation of electron binding energies by using configurations generated by Born-Oppenheimer molecular dynamics of PNA in water. The fundamental gap (Eg) of PNA in water was estimated from the first ionisation energy (IE) and the first vertical electron affinity VEA (Eg=IE-VEA). In liquid water Eg is predicted to be 6.5±0.5eV (OVGF), which is ∼3.3eV greater than the experimental optical gap (3.25eV).