Knowledge Bank

A new resonance Raman spectrometer tunable between 217-800 nm has been constructed for studies of aromatic molecules with absorption bands 217-260 nm. The excitation source is a high-power Nd Yag laser which is frequency doubled or tripled, and pumps a dye laser, yielding tunable light between 370-800 nm. The dye laser light is either mixed with the 1.06 $\mu m$ Yag fundamental, frequency doubled, or frequency doubled and mixed with the 1.06 $\mu m$ radiation to yield light between 217-420 nm. The spectrometer uses reflective collection optics to avoid chromatic aberrations and the Raman light is dispersed by using either a triple or high resolution modified double monochromator. The Raman scattered light is detected by using intensified Reticon detector which is gated on during the 4 nsec Yag laser pulse. The gating decreases interference from sample fluorescence. The novel features of the instrument will be discussed in the context of the sampling methodologies required for UV resonance Raman measurements using pulsed laser excitation sources.