SINGLE-CRYSTAL AND POLYCRYSTALLINE CIRCULAR-DICHROISM OF NI(EN)(3)(NO3)(2) BY MEANS OF VISIBLE AND NEAR-INFRARED STEP-SCAN FOURIER-TRANSFORM SPECTROSCOPY WITH MIRAGE DETECTION ((SFT)-F-2-PTD-CD)

The transverse mirage effect (photothermal deflection) has been used w ith step-scan Fourier transform interferometry to measure the circular dichroism (CD) of enantiomorphic single crystals and polycrystalline powders of Ni(en)(3)(NO3)(2) in the visible and near infrared. Compari son of the single crystal and polycrystalline ligand field CD spectra shows clearly that the (3)A(1) level is higher than the (3)E(a) and th at R(E) > R(A). The adiabatic trigonal splitting is estimated to be on the order of 50 cm(-1) The (SFT)-F-2-PTD-CD spectra have been measure d with low frequency circular polarization modulation provided by a pa ir of tandem beat-frequency photoelastic modulators. The results illus trate the ability of (SFT)-F-2-PTD-CD to determine the sign and relati ve magnitude of the rotational strength of enantiomorphic materials, p articularly those which are opaque and/or strongly Light scattering.