Knowledge Bank

We have constructed a new Raman optical activity (ROA) spectrometer at Syracuse University that is equipped with a charge coupled device (CCD) detector, and zeroth-order quarter wave plates held in computer-controlled, motorized rotation mounts. Precise polarization modulation can be carried out for both the incident and scattered beams, either separately as in incident (ICP) and scattered (SCP) circular polarization modulation ROA, or synchronously in-phase ($DCPI$) or out-of-phase dual circular polarization ($DCP\Pi$) ROA. We have carried out a variety of CP ROA measurements using both right-angle and backward scattering geometry. To date, we find that the depolarized Raman and ROA setup associated with backscattering $DCPI$ measurements is the optimum ROA configuration for the instrument that we have constructed. Examples of ROA spectra measured with this instrument will be presented which include backscattering $DCPI$ spectra of amino acids, sugars and peptides measured in either $H2O$ or $D2O$. Comparisons will also be presented for various forms of CP ROA together with a comparison of the theoretical expressions associated with these forms.""