Polaris instrument

A different heating protocol was used for the experiment with the Polaris instrument at ISIS (see Figure 3). Here a reference diffraction pattern was collected at room temperature while the furnace was initially evacuated, then the sample was heated rapidly up to a selected temperature (e.g., 1500,1550,1600,1700,andl800 °C) where it was held constant for an extended period during which a series of diffraction patterns, each of 15 minutes duration, were collected. The total time spent at each elevated temperature was manually controlled, based on the level of decomposition observed in the diffraction patterns as they were collected. At the end of each high temperature measurement the furnace was cooled to room temperature. 

Figure 3. The heating protocol used during the experimentwith the Polaris instrument...

A wide variety of FTIR instruments have been used to obtain PA-FTIR spectra. A cursory examination of the literature reveals some of the instruments used JEOL JIR-5500 IBM IR-95, IR-98,9195 Bruker IFS 66, IFS 88, IFS 113V Perkin Elmer 1750,1760-X, 1800 Bomen DA 3.02 Nicolet 20 SX, 20 DXB, SX-170, 7199, 740, 800 Mattson Cygnus 100, Sirius 100, Polaris Digilab FTS-10, FTS-10M, FTS-11, FTS-15, FTS-20, FTS-20E, FTS-60, FTS-65, FTS-6000 Laser Precision Analytical (Analect) RFX-75 and Analect FX-260. The Laser Precision Analytical Instrument required extensive modification. The list is only intended to indicate the wide variety of different instruments which have been used and may not be complete. The normal adjustments for maximum performance should be made, beam splitter alignment, etc. The source aperture, if any, should be opened fully for maximum source intensity. The gain control and other adjustments for best operation at each of the different mirror velocities to be used should be made. The... 

Much as he would like to claim it for his own, the viewpoint just set forth is not original with the present author. It is already implicit in the classical work of Werner Kuhn, . a man far ahead of his time in the field of optical activity, and it may also be found to varying degrees in the work of Condon, Eyring, > > Kauz-mann, Moffitt, > > and others. What makes it so timely now is that experimentalists such as Djerassi and Klyne, taking advantage in their work of the recent advances in polari-metric instrumentation, have stimulated theoretical progress to the point where it is possible, within limits, to feasibly characterize the optical activity associated with a particular electronic transition in terms of experimentally accessible parameters. And it can be shown that these parameters, which are of much the same kind that one encounters in ordinary optical absorption spectroscopy, do contain important molecular information that is unavailable elsewhere. 

---