Sensitive Optical Multichannel Spectrometer for Time-Resolved Resonance Raman Studies of Transient Photomerocyanines

A sensitive time-resolved Raman spectrometer for structural studies of short-lived species, up to the ns time range, is described. Raman spectra are memorized onto the target of the camera detection head of a modified CODERG UF 76 multichannel spectrometer. To process the spectral information each spectrum is digitized over 500 points and transferred to a PDP 11 minicomputer by a home-built line integrating video digitizer; this design allows very low intensity spectra to be recorded. We have used this apparatus to obtain resonance Raman spectra, excited by a 30 ns, 531 nm laser pulse, of short-lived pyrrolidinic photomerocyanines in toluene solutions. The assignment of certain Raman lines is proposed, providing details about the structure of transient species.