Resonance Raman spectroscopic and density functional theory study of p-nitroacetophenone (PNAP)

Resonance Raman spectra of p-nitroacetophenone(PNAP) have been obtained in resonance with the charge-transfer (CT) band using 252.7, 266 and 273.9 nm in methanol solvent. The spectra indicate that the Franck–Condon region photodissociation dynamics have multidimensional character with motion mainly along the CO stretching ν8(1691 cm−1) and the benzene ring stretch ν10(1593 cm−1). A preliminary resonance Raman intensity analysis was done and the results for PNAP were compared with nitrobenzene and aceptophenone. Our results indicate that –NO2 is more photoactive than –COCH3. The isomerization process of PNAP takes place somewhere after the wave packet leaves the Franck–Condon region.