INFRARED AND RAMAN VIBRATIONAL OPTICAL ACTIVITY: Theoretical and Experimental Aspects

Abstract

Advances in the field of vibrational optical activity (VOA) are reviewed over the past decade. Topics are surveyed with an emphasis on the theoretical and instrumental progress in both vibrational circular dichroism (VCD) and Raman optical activity (ROA). Applications of VOA to stereochemical and biological problems are reviewed, with a bias toward new kinds of experiments made possible by theoretical and instrumental advances. In the field of VCD, the most notable advances have taken place in the quality and size of ab initio calculations of VOA intensities and in the quality of step-scan Fourier transform instrumentation. For ROA, the most dramatic progress has occurred in the areas of theoretical formulation and high-throughput instrumentation. Applications of VOA now include all major classes of biological and pharmaceutical molecules. VOA's importance as a diagnostic tool will likely grow as the control of molecular chirality increases in research and industrial areas.

Nuclear velocity perturbation theory for vibrational circular dichroism: An approach based on the exact factorization of the electron-nuclear wave function

“…The symbol ∂ ν α is used to indicate a spatial derivative along the α direction of the position of the ν-th nucleus and e labels the (unperturbed) adiabatic excited states. The TDPES, up to within first-order terms, is labeled (1) . It is worth noting that in writing Eq.…”

“…Here d e0,να (R) is the α-th Cartesian component of the non-adiabatic coupling vector, corresponding to the ν-th nucleus, between the unperturbed ground-state and the excited state e, whereas the frequency ω e0 (R) is the the energy difference (divided by ) between the excited (e) and the ground (0) R |ϕ R (t) r is real ∀ R, t, which is allowed as gauge condition, we imply the orthogonality of ϕ (1) R,να (r) and ϕ…”

“…Vibrational circular dichroism (VCD) [1][2][3] in molecules refers to the difference in absorption of left and right circularly polarized light in the infrared region of the electromagnetic spectrum. In contrast to circular dichroism, that originates in electronic transitions, VCD is the difference in interaction of a molecule with radiation of opposite circular polarizations when it undergoes vibrational transitions.…”

Discriminating early stage Aβ42 monomer structures using chirality-induced 2DIR spectroscopy in a simulation study

“…Circular dichroism (CD) is an important example of such signals in linear spectroscopy (39)(40)(41), broadly applied for probing the folding states of proteins and their conformational stability. We recently theoretically proposed a chirality-induced 2DIR (CI-2DIR) technique (37), in which the structural sensitivity can be greatly enhanced by a judicious choice of polarization configurations aimed at chiral structures.…”

Observation and calculation of vibrational circular birefringence: A new form of vibrational optical activity

“…Vibrational optical activity (VOA) 6,[8][9][10][11] is comprised of two principal areas, infrared vibrational circular dichroism (VCD) 12 and vibrational Raman optical activity (ROA), 13,14 based on infrared absorption spectroscopy and Raman scattering spectroscopy, respectively. Both arise from a differential response with respect to left (LCP) and right circularly polarized (RCP) radiation for a chiral molecule undergoing a vibrational transition.…”