Core-resonant circular dichroism (CD) signals are induced by molecular chirality and vanish for achiral molecules and racemic mixtures. The highly localized nature of core excitations makes them ideal probes of local chirality within molecules. Simulations of the circular dichroism spectra of several molecular families illustrate how these signals vary with the electronic coupling to substitution groups, the distance between the X-ray chromophore and the chiral center, geometry, and chemical structure. Clear insight into the molecular structure is obtained through analysis of the X-ray CD spectra.
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Enhancing circular dichroism by chiral hotspots in silicon nanocube dimers
Circular dichroism (CD) spectroscopy, which measures the differential absorption of circularly polarized light with opposite handedness, is an important technique to detect and identify chiral molecules in chemistry, biology and life sciences. However, CD signals are normally very small due to the intrinsically weak chirality of molecules. Here we theoretically investigate the generation of chiral hotspots in silicon nanocube dimers for CD enhancement. Up to 15-fold enhancement of the global optical chirality is obtained in the dimer gap, which boosts the CD signal by one order of magnitude without reducing the dissymmetry factor. This chiral hotspot originates from the simultaneous enhancement of magnetic and electric fields and their proper spatial overlap. Our findings could lead to integrated devices for CD spectroscopy, enantioselective sensing, sorting and synthesis.
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- Award ID(s):
- 1654192
- NSF-PAR ID:
- 10058263
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 10
- Issue:
- 18
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 8779 to 8786
- 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
- Journal Article:
- https://doi.org/10.1039/c8nr00902c
