Vibrational circular dichroism (VCD) is a measure of the differential absorption of left versus right circularly polarized infrared radiation due to the vibrational transitions of chiral molecules. This is a new branch of molecular spectroscopy with potential for providing the three dimensional structure of molecules in solution phase. Currently VCD measurements can be made from anywhere in the near infrared to about 600 cm-l.
The specific aims of this project are to extend these VCD measurements into the far infrared region, 600 - 1 cm-l and to identify the use of low frequency vibrations or deducing the molecular stereochemistry. For these measurements a Marrin-Puplett interferometer based far infrared instrument will be used. In this instrument, linearly polarized input beam is converted into the desired polarization state by moving one of the two roof-top mirrors. The optically active samples are placed at the output end of the interferometer and sine Fourier transform of the interferograms recorded provides the VCD information. The experiments will be carried out on carbohydrates and other biologically significant molecular systems to understand the relation of stereochemistry to the VCD associated with low frequency vibrations, such as torsional and skeletal variations. With the establish of such relations, applications will be projected to the stereochemical investigations on the chemical species that play vital role in life cycle. The analytical application of VCD spectroscopy in the life sciences can thus be established.
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