FREQUENCY/WAVELENGTH CALIBRATION OF MULTIPURPOSE MULTICHANNEL RAMAN SPECTROMETERS .2. CALIBRATION FIT CONSIDERATIONS AND CALIBRATION STANDARDS

Approaches for frequency/wavelength calibration of multichannel Raman spectrometers are presented. These approaches are directed towards practical use in laboratories in which multipurpose or specialized applications result in the need for frequent spectrometer calibration. These approaches are also useful when the sample type or configuration does not permit calibration by more routine methods. Guidelines are presented for effective use of polynomials commonly found in spectrometer calibration software for conversion of pixel number to either wavenumber or wavelength. Guidelines for the selection and use of Raman calibration standards are also presented. Standards currently used for calibration of Raman spectrometers are reviewed. Improved frequency data for indene and the Ar+ plasma lines are presented, along with frequency data for two materials (imidazole and alpha-cyclodextrin) which are recommended for use as solid Raman standards.