The development of efficient techniques to distinguish mirror images of chiral molecules (enantiomers) is very important in both chemistry and physics. Enantiomers share most molecular properties except, for instance, the absorption of circularly polarized light. Enantiomer purification is therefore a challenging task that requires specialized equipment. Strong coupling between quantized fields and matter (e.g. in optical cavities) is a promising technique to modify molecular processes in a non-invasive way. The modulation of molecular properties is achieved by changing the field characteristics. In this work, we investigate whether strong coupling to circularly polarized electromagnetic fields is a viable way to discriminate chiral molecules. To this end, we develop a nonperturbative framework to calculate the behavior of molecules in chiral cavities. We show that in this setting the enantiomers have different energies -- that is, one is more stable than the other. The field-induced energy differences are also shown to give rise to enantiospecific signatures in rotational spectra.

Strong Coupling in Chiral Cavities: Nonperturbative Framework for Enantiomer Discrimination

Quantum chemical methods for the description of molecular polaritonic states in the strong coupling regime based on the Pauli-Fierz Hamiltonian are introduced. Based on a quantum electrodynamic Hartree-Fock (QED-HF) reference, a QED Møller-Plesset perturbation theory of second order for the electronic ground state and a second order quantum electrodynamic algebraic diagrammatic construction scheme for the polarization propagator [QED-ADC(2)] for excited electronic states have been derived, implemented, and tested for polaritons in hydrogen fluoride. Analogous approaches based on a standard non-polaritonic HF reference are also presented and thoroughly compared, both algebraically and numerically, to those based on the QED-HF reference. Furthermore, a promising route to approximate QED-ADC methods based on a unitary transformation of the algebraic expression into a restricted state space is outlined showing excellent agreement in second order with QED-ADC(2). All presented novel methods are compared to and tested against other existing ab initio approaches, mostly QED coupled cluster theory, including single and double excitations, and show qualitative agreement at a reduced computational effort.

https://pubs.aip.org/aip/jcp/article-pdf/doi/10.1063/5.0142403/16794111/124128_1_online.pdf

Perturbation theoretical approaches to strong light-matter coupling in ground and excited electronic states for the description of molecular polaritons.

Investigating Molecular Exciton-Polaritons using Many-body Electronic Structure Theory with Cavity Quantum Electrodynamics

Coupling molecules to the quantized radiation field inside an optical cavity creates a set of new photon–matter hybrid states called polariton states. We combine electronic structure theory with quantum electrodynamics (QED) to investigate molecular polaritons using ab initio simulations. This framework joins unperturbed electronic adiabatic states with the Fock state basis to compute the eigenstates of the QED Hamiltonian. The key feature of this “parametrized QED” approach is that it provides the exact molecule–cavity interactions, limited by only approximations made in the electronic structure. Using time-dependent density functional theory, we demonstrated comparable accuracy with QED coupled cluster benchmark results for predicting potential energy surfaces in the ground and excited states and showed selected applications to light-harvesting and light-emitting materials. We anticipate that this framework will provide a set of general and powerful tools that enable direct ab initio simulation of exciton polaritons in molecule–cavity hybrid systems.

https://pubs.acs.org/doi/pdf/10.1021/acs.jpclett.3c01294

Investigating Molecular Exciton Polaritons Using Ab Initio Cavity Quantum Electrodynamics

Experimental studies indicate that optical cavities can affect chemical reactions, through either vibrational or electronic strong coupling and the quantized cavity modes. However, the current understanding of the interplay between molecules and confined light modes is incomplete. Accurate theoretical models, that take into account inter-molecular interactions to describe ensembles, are therefore essential to understand the mechanisms governing polaritonic chemistry. We present an ab-initio Hartree-Fock ansatz in the framework of the cavity Born-Oppenheimer approximation and study molecules strongly interacting with an optical cavity. This ansatz provides a non-perturbative, self-consistent description of strongly coupled molecular ensembles taking into account the cavity-mediated dipole self-energy contributions. To demonstrate the capability of the cavity Born-Oppenheimer Hartree-Fock ansatz, we study the collective effects in ensembles of strongly coupled diatomic hydrogen fluoride molecules. Our results highlight the importance of the cavity-mediated inter-molecular dipole-dipole interactions, which lead to energetic changes of individual molecules in the coupled ensemble.

Cavity-Born-Oppenheimer Hartree-Fock Ansatz: Light-matter Properties of Strongly Coupled Molecular Ensembles

The enantiopurification of racemic mixtures of chiral molecules is important for a range of applications. Recent work has shown that chiral group-directed photoisomerization is a promising approach to enantioenrich racemic mixtures of BINOL, but increased control of the diasteriomeric excess (de) is necessary for its broad utility. Here we develop a cavity quantum electrodynamics (QED) generalization of time-dependent density functional theory and demonstrate computationally that strong light-matter coupling can alter the de of the chiral group-directed photoisomerization of BINOL. The relative orientation of the cavity mode polarization and the molecules in the cavity dictates the nature of the cavity interactions, which either enhance the de of the (R)-BINOL diasteriomer (from 17% to ≈40%) or invert the favorability to the (S)-BINOL derivative (to ≈34% de). The latter outcome is particularly remarkable because it indicates that the preference in diasteriomer can be influenced via orientational control, without changing the chirality of the directing group. We demonstrate that the observed effect stems from cavity-induced changes to the Kohn-Sham orbitals of the ground state.

Enhanced Diastereocontrol via Strong Light-Matter Interactions in an Optical Cavity.

Enabling Lower Energy Light Harvesting in Stilbene-Based Photomechanical Polymers via Triplet Sensitization

Photoresponsive polymers are commonly used for applications such as controlled drug delivery, patterned thin films of hydrogels and polymer brushes, photodegradable materials, and liquid crystal actuators.1 Photoresponsive polymers are unique as they can change shape when exposed to a certain wavelength, intensity, or polarization of light while not requiring an electrical circuit or tethered power supply. However, the majority of photoresponsive polymers are based on the azobenzene moiety and the conversion of light into mechanical work is often inefficient. This work summarizes the relaxation behavior of a novel photopolymer film derived from stilbene and its unsensitized analog. Experiments are conducted quantifying the relaxation behavior of the films. The relaxation behavior of the photopolymer is analyzed by comparing fractional order and integer order Maxwell models. All results are statistically validated using Bayesian uncertainty methods to obtain posterior densities for the model parameters. It is shown that the fractional order Maxwell model is superior based on errors that are an order of magnitude lower than the integer order Maxwell model.

Characterization of fractional viscoelastic relaxation behavior of a photopolymer film

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Enhanced Diastereocontrol via Strong Light–Matter Interactions in an Optical Cavity”Nam VuNam VuMore by Nam Vu, Grace M. McLeodGrace M. McLeodMore by Grace M. McLeodhttps://orcid.org/0000-0003-4018-8864, Kenneth HansonKenneth HansonMore by Kenneth Hansonhttps://orcid.org/0000-0001-7219-7808, and A. Eugene DePrince III*A. Eugene DePrince IIIMore by A. Eugene DePrince IIIhttps://orcid.org/0000-0003-1061-2521Cite this: J. Phys. Chem. A 2023, 127, 5, 1386Publication Date (Web):January 30, 2023Publication History Received15 January 2023Published online30 January 2023Published inissue 9 February 2023https://doi.org/10.1021/acs.jpca.3c00330Copyright © 2023 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views191Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (795 KB) Get e-Alertsclose Get e-Alerts 

https://pubs.acs.org/doi/pdf/10.1021/acs.jpca.3c00330

Grace M McLeod

Papers

Enhanced Diastereocontrol via Strong Light-Matter Interactions in an Optical Cavity.

Enabling Lower Energy Light Harvesting in Stilbene-Based Photomechanical Polymers via Triplet Sensitization

Characterization of fractional viscoelastic relaxation behavior of a photopolymer film

Correction to "Enhanced Diastereocontrol via Strong Light-Matter Interactions in an Optical Cavity".