Experimental absorption spectra in the IR and vis-uv are obtained in our labs with commercial instrumentation, as is electronic circular dichroism (ECD) in the uv. To realize the experimental aspects of vibrational CD (VCD) in the IR, we have constructed instrumentation capable of measuring circular dichroism in the IR down to 600 cm^-1. Our original dispersive spectrometer, based on a J-Y 1m monochromator with various gratings, a C-rod source for IR (W-I or Xe for vis), Hinds modulator and various detectors, with the signal demodulated via a 3-lockin detection system under computer control, was originally assembled and optimized by Eric Su and Vic Heintz. This VCD instrument followed the early work by Nafie, Keiderling and Stephens (1976) on near IR VCD that was progressively extended to the mid IR, computer interfaced, converted to the C-rod, as summarized in some of our reviews (1981, 1990, 2003). This also operates in the visible and can accomodate a magnet for MVCD studies of crystals and solutions (work of Barbara Kozikowski). A later separate instrument, constructed by Gorm Yoder, is more compact and was optimized for the midIR, especially the C=O stretch region.

Various FTIR-based VCD instruments capable of measurements at moderate resolution and high S/N have been assembled in the lab by Petr Malon, Ryong Yoo and the latest by Paul Croatto. The current version uses a Digilab FTS60A (Win IR Pro-3) capable of 0.1 cm^-1 resolution, step-scan (developed by Baoliang Wang) and digital signal processing (DSP, with Joe Hilario in collaboration with Dave Drapcho of Digilab) It can measure VCD in rapid scan, slow- (or continuous step-) scan and DSP (step-scan with full digitization of the time varying signal) modes. Even measurement with a spinning quarter wave plate modulator has been demonstrated (Malon). A series of reports from our lab in Applied Spectroscopy addressed this as well as other FT-VCD developments including: artifact control using lens focusing, determination of zero path difference without baseline offset and phase problems of high resolution FT-MVCD, step-scan FT-VCD, and most recently DSP signal processing. However, for measurements, of single broad bands, such as are often of interest for proteins in aqueous solution, the FTIR advantages do not benefit the S/N in practice, and the dispersive approach remains more useful in our lab. This may change with the commercialization of FT-VCD. This instrument is now being modified for stop-flow FTIR measurements (Joe Hilario and Qi Xu). Routine FTIR and temperature variation experiments (using interfaced and manual Neslab controllers) are obtained on an older Digilab FTS -40, converted to WinIR. All of these are in 4355 SES.

For measuring ROA, a cooled multi-channel photodiode array detector-based Raman spectrometer with a J-Y 0.67m monochromator, a Coherent Innova 4W Ar⁺ laser, and a KDP electro-optic modulator was constructed originally by Mark Vavra and later upgraded by Vladimir Baumruk and Cheok Tam for use in a back scattering mode. It is used for normal Raman, particularly of proteins (by Jan Kubelka), with a 90^o scattering sampling configuration. A shared use, J-Y Ramanor (double 1m monochromator), donated by Amoco, having conventional and microscope sampling and CCD and photon counting detection, is available for higher resolution, but lower sensitivity Raman, and has been of use in a few small molecule studies (Tam). These set-ups are located in 4359 SES.

Beyond the above, commercial instrumentation (shared with other groups in a Departmental lab, located in 4315 SES) includes a Jasco J-810 CD with a BioLogic SFM400 stop-flow, quench-flow and fluorescence, titration and temperature control attachments, a Cary 17DX and OLIS modified Cary 14 uv-vis spectrometer, and a Digilab FTS-40.

In the past, as an unrelated project, a two-photon excitation fluorescence spectrometer was constructed by Barbara Kozikowski with a N₂-laser pumped dye (upgraded by Ryong Yoo for YAG pumping) for studies of electronic excited states transition metal complexes, and then modified by Sang Lee to be part of a molecular-beam apparatus usable for multi-photon ionization studies. This is now disassembled and in storage.

To learn more about these developments, check out our publications on instrumentation. However, the design of our VCD and ROA instruments is often just summarily described in the original literature focussed on applications, but is fully documented in theses of the students involved in its development. These are available from University Microfilms or (for a fee covering copying charges) personal use copies can be obtained from the author or from us, provided no copyright problems occur.

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