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Updated: Nov 30, 2025

A Technical Guide for Performing Spectroscopic Measurements on Metal-Organic Frameworks
Published on: April 28, 2023
Monitoring aromatic ring-currents in Mg-porphyrin by time-resolved circular dichroism
Yeonsig Nam1, Jérémy R Rouxel, Jin Yong Lee
1Department of Chemistry, Physics and Astronomy, University of California, Irvine, 92697-2025, USA. jrouxel@uci.edu smukamel@uci.edu yeonsign@uci.edu.
Abstract:
Time-resolved circular dichroism signals (TRCD) in the X-ray regime can directly probe the magnitude and the direction of ring currents in molecules. The electronic ring currents in Mg-porphyrin, generated by a coherent superposition of electronic states induced by a circularly polarized UV pulse, are tracked by a time-delayed circularly polarized attosecond X-ray pulse. The signals are calculated using the minimal coupling Hamiltonian, which directly makes use of transition current densities. The TRCD signals obtained from the left and right circularly polarized light pump have opposite signs, revealing the direction of the ring current. Molecular aromaticity and its role in photochemical reactions such as ring opening or closure can be studied using this technique.
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