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Resonant and off-resonant Raman Optical Activity signals in the X-ray regime (XROA) are predicted. XROA is a chiral-sensitive variant of the spontaneous Resonant Inelastic Scattering (RIXS) signal. Thanks to the highly localized nature of core excitations, these signals provide a direct probe of local chirality with high sensitivity to the molecular structure. We derive sum-over-states expressions for frequency domain XROA signals and apply them to tyrosine at the nitrogen and oxygen K-edges. Time-resolved extensions of ROA made possible by using additional pulses are briefly outlined.
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Hyper-Raman optical activity of biologically relevant chiral molecules
The optical activity of Raman scattering provides insight into the absolute configuration and conformation of chiral molecules. Applications of Raman optical activity (ROA) are limited by long integration times due to a relatively low sensitivity of the scattered light to chirality (typically 10^-3 to 10^-5). We apply ROA techniques to hyper-Raman scattering using incident circularly polarized light and a right-angle scattering geometry. We explore the sensitivity of hyper- Raman scattering to chirality as compared to spontaneous Raman optical activity. Using the excitation wavelength at around 532 nm, the photobleaching is minimized, while the hyper-Raman scattering benefits from the electronic resonant enhancement. For S/R-2-butanol and L/D-tartaric acid, we were unable to detect the hyper-Raman optical activity at the sensitivity level of 1%. We also explored parasitic thermal effects which can be mitigating by varying the repetition rate of the laser source used for excitation of hyper-Raman scattering.
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- Award ID(s):
- 1810995
- PAR ID:
- 10173527
- Date Published:
- Journal Name:
- Hyper-Raman optical activity of biologically relevant chiral molecules
- Page Range / eLocation ID:
- 84
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1117/12.2545530
