Cavity-molecule interactions
Strong coupling of photonic and molecular degrees of freedom can lead to the formation of hybrid light-matter states known as polaritons that can exhibit significantly different properties relative to the original uncoupled states. For example, as the animation below shows, the optical properties of a molecule can be dramatically alterered via sufficiently strong coupling to a cavity. In this case, an absorption feature in formaldehyde (described by a cavity quantum electrodynamics [QED] generalization of equation-of-motion [EOM] coupled-cluster [CC] theory and a minimal basis) splits into a lower and upper polariton state, separated by what is called the Rabi splitting, which, in this case, can exceed 1 eV.
We have developed algorithms for mean field (Hartree-Fock, density functional theory) and correlated (CC, EOM-CC, variational two-electron reduced density matrix theory [v2RDM]) ab initio cavity QED calculations in our package hilbert, which is a plugin to the Psi4 electronic structure package. You can read about the theory and application of QED-CC, EOM-QED-CC, and QED-v2RDM here:
M. D. Liebenthal and A. E. DePrince III, J. Chem. Phys. 161, 064109 (2024).
The orientation dependence of cavity-modified chemistry
J. J. Foley IV, J. F. McTauge, and A. E. DePrince III, Chem. Phys. Rev. 4, 041301 (2023).
Ab initio methods for polariton chemistry
M. D. Liebenthal, N. Vu, A. E. DePrince III, J. Phys. Chem. A 127, 5264-5275 (2023).
Assessing effects the effects of orbital relaxation and the coherent-state transformation in in quantum electrodynamics density functional and coupled-cluster theories
N. Vu, G. M. McLeod, K. Hanson, and A. E. DePrince III, J. Phys. Chem. A 126, 9303-9312 (2022).
Enhanced diastereocontrol via strong light-matter interactions in an optical cavity
J. D. Mallory and A. E. DePrince III, Phys. Rev. A, 106, 053710 (2022).
Reduced-density-matrix-based ab initio cavity quantum electrodynamics
M. D. Liebenthal, N. Vu, and A. E. DePrince III, J. Chem. Phys. 156, 054105 (2022).
Equation-of-motion cavity quantum electrodynamics coupled-cluster theory for electron attachment
A. E. DePrince III, J. Chem. Phys. 154, 094112 (2021).
Cavity-modulated ionization potentials and electron affinities from quantum electrodynamics coupled-cluster theory
To learn more about ab initio approaches to the description of quantized light-matter interactions, check out the seminar below. The discussion of cavities begins at 26:20.
Plasmon-molecule interactions
We have developed a quantum-mechanical mean-field method to describe plasmon-molecule interactions in the time domain. As a silly proof of principle, consider the interaction of H2 with a hypothetical plasmonic particle whose resonance overlaps with the Σg+ to Σu+ excitation in H2. The interference between the plasmon and molecular excitations gives rise to a Fano-like resonance whose character depends strongly on the alignment of external electric fields and the molecular axis of H2.
D. R. Nascimento and A. E. DePrince, III, J. Chem. Phys. 143, 214104 (2015).
Modeling plasmon-molecule interactions using quantized radiation fields within time-dependent electronic structure theory