Vibrational circular dichroism (VCD) can be used to determine the absolute configuration of chiral compounds. It can also be used to monitor the course of stereospecific reactions and to study the reactions and to study the secondary structures of proteins and peptides. It is a spectroscopic technique which detects differences in attenuation of left and right circularly polarized light passing through a sample. It is basically circular dichroism spectroscopy in the infrared and near infrared ranges. Because VCD is sensitive to the mutual orientation of distinct groups in a molecule, it provides three-dimensional structural information. Thus, it is a powerful technique as VCD spectra of enantiomers can be simulated using ab initio calculations, thereby allowing the identification of absolute configurations of small molecules in solution from VCD spectra.