Effect of electronic excitation on nuclear magnetic shielding as illustrated by nuclear spin optical rotation (NSOR) in liquids

Highlights: • The near resonance effect on the optical chemical shift in NSOR is theoretically studied. • The dressed state theory is employed to explore the near resonance effect. • New optical chemical shift line in NSOR spectrum due to excited state molecule is estimated. • Possibility of detecting the new optical chemical line is discussed. Conventional NMR is generally a technique for electronic ground state molecules. In this paper, the effect of electronic excitation on nuclear magnetic shielding is theoretically illustrated by Nuclear Spin Optical Rotation (NSOR) in liquids. The near-resonance effect on the optical chemical shift in NSOR is explored by using the dressed state theory. The results indicate that in the NSOR spectrum of a molecule with nucleus I = 1/2, such effect can induce a new optical chemical shift line with the circular frequency different from that of the ground state. From it the NMR shielding of a molecule in the electronic excited state can be got directly and used to analyze excited molecule structure in liquids. For multi-nuclei molecules, the result applies to each nucleus.