Structural Sensitivity without Chirality: Observation of Magnetic Raman Optical Activity outside Resonance.

Magnetic Raman optical activity (MROA) has been considered to be confined to a few systems fulfilling the resonance conditions. In a far-from-resonance (FFR) case when the systems do not absorb the excitation radiation, it has not been reported. However, we find it present in many common organic molecules. The underlying theory was elaborated, and a procedure for quantum chemical simulations of MROA intensities was implemented. The spectral features predicted at the density functional theory (DFT) level reasonably agree with the observations, describe the trends in the experimental data, and allow one to understand the phenomenon more deeply. It appears that not only do molecules have specific MROA patterns but the intensities are also very much dependent on the conformation. The sensitivity to the structure in solutions without the need for intrinsic molecular chirality makes MROA a unique tool for analytical chemistry and potentially usable for conformational studies of both chiral and achiral molecules in solutions and other liquids.