The charge excitation in the Raman process as correlated from a classical theory for Raman optical activity: the case study of (+)-(R)-methyloxirane

A Review of Chinese Raman Spectroscopy Research Over the Past Twenty Years

This paper introduces the major Chinese research groups in the fields of biomedicine, food safety, environmental testing, material research, archaeological and cultural relics, gem identification, forensic science, and other research areas of Raman spectroscopy and combined methods spanning the two decades from 1997 to 2017. Briefly summarized are the research directions and contents of the major Chinese Raman spectroscopy research groups, giving researchers engaged in Raman spectroscopy research a more comprehensive understanding of the state of Chinese Raman spectroscopy research and future development trends to further develop Raman spectroscopy and its applications.

Intra-molecular enantiomerism in R-(+)-Limonene as evidenced by the differential bond polarizabilities

We propose an algorithm to obtain the differential bond polarizabilities from the Raman and Raman optical activity (ROA) spectral intensities. The signs of the differential bond polarizabilities of R-Limonene demonstrate that there is intra-molecular enantiomerism in its six membered ring structure. That is, the signs of the differential bond polarizabilities around the six membered ring are inversed under an intra-molecular mirror reflection. This is similar to what happens in the right and left handed chiral isomers under a mirror conversion.

Stereostructural implication by the differential bond polarizability: ROA intensity study of chiral s 2-amino 1-propanol

The bond polarizability and differential bond polarizability are introduced to interpret the Raman and Raman optical activity (ROA) intensities, calculated by the ab initio method. Chiral S 2-amino 1-propanol is taken as a model molecule. Through these bond polarizabilities, we observe that symmetric and antisymmetric coordinates are, respectively, more significant in Raman and ROA. It is noted that in S 2-amino 1-propanol those bonds lying on a common plane share the same differential bond polarizability sign while that of the asymmetric C-H bond which protrudes out of the plane possesses the opposite sign. We conclude that ROA can offer more stereostructural implications than Raman and that the differential bond polarizability is potentially the appropriate parameter in interpreting the 3D configuration of a molecule.

The asymmetry of (-)α-pinene as revealed from its raman optical activity spectrum

An algorithm is employed to retrieve the differential bond polarizabilities of the C-C bonds from the Raman optical activity (ROA) spectrum of (-)α-pinene. (-)α-pinene possesses two asymmetric centers (carbon atoms) and a local mirror symmetry. These differential bond polarizabilities show the characteristics of the asymmetry around the asymmetric carbons with respect to the mirror reflection. This analysis is accompanied along with the ROA mode signatures and the calculated β(G ')(2) and β(A)(2) which show the ROA coupling mechanisms involving the electric/magnetic dipoles and the electric dipole/quadrupole, respectively.