Vibrational circular dichroism

Vibrational circular dichroism (VCD) is a <a href="/facts/Spectroscopy/mj71FuNK">spectroscopic</a> technique which detects differences in attenuation of left and right <a href="/facts/Circular_polarization/fYQvT0mI">circularly polarized light</a> passing through a sample. It is the extension of <a href="/facts/Circular_dichroism/sMKgzpF2">circular dichroism</a> spectroscopy into the <a href="/facts/Infrared/44XdJNcc">infrared</a> 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. Among such quantum computations of VCD spectra resulting from the chiral properties of small organic molecules are those based on <a href="/facts/Density_functional_theory/wwz4Gqdg">density functional theory</a> (DFT) and gauge-including <a href="/facts/Atomic_orbitals/tKhgl6mL">atomic orbitals</a> (GIAO). As a simple example of the experimental results that were obtained by VCD are the spectral data obtained within the carbon-hydrogen (C-H) stretching region of 21 <a href="/facts/Amino_acid/WDxYwBny">amino acids</a> in <a href="/facts/Heavy_water/3dbSrTw5">heavy water</a> solutions. Measurements of vibrational optical activity (VOA) have thus numerous applications, not only for small molecules, but also for large and complex biopolymers such as muscle proteins (<a href="/facts/Myosin/7zGeRkpS">myosin</a>, for example) and <a href="/facts/DNA/nB89Iauz">DNA</a>.

Vibrational circular dichroism open-in-new

Vibrational circular dichroism