Cavity-enabled enhancement of ultrafast intramolecular vibrational redistribution over pseudorotation

Journal Article · 17 November 2022 · Science

DOI:https://doi.org/10.1126/science.add0276· OSTI ID:2421017

Chen, Teng-Teng ^[1]; Du, Matthew ^[2]; Yang, Zimo ^[3]; Yuen-Zhou, Joel ^[2]; Xiong, Wei ^[4]

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1. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.; OSTI
2. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
3. Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, USA.
4. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.; Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, USA.; Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, USA.

Vibrational strong coupling (VSC) between molecular vibrations and microcavity photons yields a few polaritons (light-matter modes) and many dark modes (with negligible photonic character). Although VSC is reported to alter thermally activated chemical reactions, its mechanisms remain opaque. To elucidate this problem, we followed ultrafast dynamics of a simple unimolecular vibrational energy exchange in iron pentacarbonyl [Fe(CO)₅] under VSC, which showed two competing channels: pseudorotation and intramolecular vibrational-energy redistribution (IVR). We found that under polariton excitation, energy exchange was overall accelerated, with IVR becoming faster and pseudorotation being slowed down. However, dark-mode excitation revealed unchanged dynamics compared with those outside of the cavity, with pseudorotation dominating. Thus, despite controversies around thermally activated VSC modified chemistry, our work shows that VSC can indeed alter chemistry through a nonequilibrium preparation of polaritons.

• Research Organization: Univ. of California, San Diego, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: SC0019188
• OSTI ID: 2421017
• Journal Information: Science, Journal Name: Science Journal Issue: 6621 Vol. 378; ISSN 0036-8075
• Publisher: AAAS
• Country of Publication: United States
• Language: English

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