Second harmonic generation by p-nitrophenol at water/air and water/heptane interfaces

Abstract
Interfacial second harmonic generation by p-nitrophenol at air/water and heptane/water interfaces has been investigated. The preliminary results indicate that the orientation of the p-nitrophenol is slightly different in the two cases, but the influence of the resonant enhancement on the two important components of the molecular hyperpolarisability (βzzz and βzxx) differs significantly in the two systems. The difference is attributed to the change in the absorption spectrum of p-nitrophenol in heptane and water.