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Abstract Selectively exciting target molecules to high vibrational states is inefficient in the liquid phase, which restricts the use of IR pumping to catalyze ground-state chemical reactions. Here, we demonstrate that this inefficiency can sometimes be solved by confining the liquid to an optical cavity under vibrational strong coupling conditions. For a liquid solution of 13 CO 2 solute in a 12 CO 2 solvent, cavity molecular dynamics simulations show that exciting a polariton (hybrid light-matter state) of the solvent with an intense laser pulse, under suitable resonant conditions, may lead to a very strong (>3 quanta) and ultrafast (<1 ps) excitation of the solute, even though the solvent ends up being barely excited. By contrast, outside a cavity the same input pulse fluence can excite the solute by only half a vibrational quantum and the selectivity of excitation is low. Our finding is robust under different cavity volumes, which may lead to observable cavity enhancement on IR photochemical reactions in Fabry–Pérot cavities.
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Theory for Cavity-Modified Ground-State Reactivities via Electron–Photon Interactions
We providea simple and intuitivetheory to explain how couplinga moleculetoan optical cavity can modifyground-statechemicalreactivityby exploitingintrinsicquantumbehaviorsof light−matterinteractions.Using the recentlydevelopedpolarizedFock statesrepresentation,we demonstratethat the change of the ground-statepotentialis achieveddue tothe scaling of diabaticelectroniccouplingswith the overlapof the polarizedFock states. Ourtheory predictsthat for a proton-transfermodel system,the ground-statebarrier height can bemodifiedthroughlight−matterinteractionswhen the cavity frequencyis in the electronicexcitationrange. Our simple theory explainsseveral recent computationalinvestigationsthatdiscoveredthe same effect. We further demonstratethat under the deep strong couplinglimitof the light and matter,the polaritonicgroundand first excitedeigenstatesbecometheMulliken−Hushdiabaticstates, which are the eigenstatesof the dipole operator.This workprovidesa simple but powerfultheoreticalframeworkto understandhow strong couplingbetweenthe moleculeand the cavity can modifyground-statereactivities.
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- PAR ID:
- 10498354
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- The Journal of Physical Chemistry A
- Volume:
- 127
- Issue:
- 32
- ISSN:
- 1089-5639
- Page Range / eLocation ID:
- 6830 to 6841
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1021/acs.jpca.3c01421
