Special Seminar
Name: Sindhana Pannir-Sivajothi
Affiliation: University of California San Diego
Title: Molecular polaritons: radiative heat transfer, chemical reactivity, and condensation
Date & Time: Thursday, 05th December at 4:00 p.m.
Venue: Rajarshi Bhattacharya Memorial Lecture Hall, Chemical Sciences Building
Abstract:
Strong coupling between vibrational transitions in molecules and photon modes results in the formation of polariton modes, which have partly-molecular and partlyphotonic character. This can be achieved when molecules are placed in various photonic structures, e.g., FabryPerot cavities. Some experiments report changes in chemical reactivity and phase transition temperatures when molecules are placed within these cavities, even in the absence of optical pumping – explaining these observations is one of the biggest challenges in polariton chemistry. Often, these changes are attributed to vibrational strong coupling; however, these systems fall under the collective strong coupling regime where many molecules couple to each photon mode, resulting in a massive number of dark modes that far outnumber the polariton ones. In this talk, I will discuss our theoretical results that highlight the role of radiative heat transfer in interpreting some of these experimental results [1,2]. I will also present a strategy to enhance polaritonic effects on chemical reactivity in the collective strong-coupling regime through polariton condensation, where the macroscopic occupation of the polariton mode counters the large number of dark modes [3]. I will conclude by summarizing the physical and chemical properties most likely to be modified under collective vibrational strong coupling.
References:
[1] Z. Brawley*, S. Pannir-Sivajothi*, J. E. Yim*, Y. R. Poh, J. Yuen-Zhou, and M. Sheldon, Vibrational weak and strong coupling modify a chemical reaction via cavity-mediated radiative energy transfer, ChemRxiv preprint (2023) (in press, Nat. Chem.).
[2] S. Pannir-Sivajothi and J. Yuen-Zhou, Blackbody radiation and thermal effects on chemical reactions and phase transitions in cavities, arXiv preprint arXiv:2402.01043 (2024).
[3] S. Pannir-Sivajothi, J. A. Campos-Gonzalez-Angulo, L. A. Martínez-Martínez, S. Sinha, and J. Yuen-Zhou, Driving chemical reactions with polariton condensates, Nat. Commun. 13, 1645 (2022).