Resonance Raman study of the solvation of p-nitroaniline in supercritical water

Abstract: Resonance Raman spectra of p-nitroaniline (pNA) have been measured in various states of water. The relative intensities of two bands assigned to the NO2 stretching mode show a large temperature dependence along the 30.4MPa isobar between ambient temperature and 669K. Along the supercritical isotherm at 668.5K, the higher frequency band shifts by 8cm−1 over the accessible density range (0.3–1.7ρ c). We also performed density-functional calculations of the Raman spectra of water clusters of pNA. The calculated changes in electronic structure and Raman spectra with cluster size are used to rationalize these experimental observations. [Copyright &y& Elsevier]