Cavity Born-Oppenheimer Coupled Cluster Theory: Towards Electron Correlation in the Vibrational Strong Light-Matter Coupling Regime

Abstract

We present a detailed derivation and discussion of cavity Born-Oppenheimer coupled cluster (CBO-CC) theory and address cavity-modified electron correlation in the vibrational strong coupling regime. Methodologically, we combine the recently proposed cavity reaction potential (CRP) approach with the Lagrangian formulation of CC theory and derive a self-consistent CRP-CC method at the singles and doubles excitations level (CRP-CCSD). The CRP-CC approach is formally similar to implicit solvation CC models and provides access to the CBO-CC electronic ground state energy minimized in cavity coordinate space on a CC level of theory. A hierarchy of linearisation schemes (lCRP-CCSD) similar to canonical CC theory systematically lifts the self-consistent nature of the CRP-CCSD approach and mitigates numerical cost by approximating electron correlation effects in energy minimization. We provide a thorough comparison of CRP-CCSD, lCRP-CCSD and CRP-Hartee-Fock methods for a cavity-modified Menshutkin reaction, pyridine$+$CH${}_3$Br, and cavity-induced collective electronic effects in microsolvation energies of selected methanol-water clusters. We find lCRP-CCSD methods to provide excellent results compared to the self-consistent CRP-CCSD approach in the few-molecule limit. We furthermore observe significant differences between mean-field and correlated results in both reactive and collective scenarios. Our work emphasizes the non-trivial character of electron correlation under vibrational strong coupling and provides a starting point for further developments in ab initio vibro-polaritonic chemistry beyond the mean-field approximation.

16 pages, 2 figures, v2: minor corrections and updates of text

References in corpus (21)

• Recent developments in the PySCF program package
• Atoms and Molecules in Cavities: From Weak to Strong Coupling in QED Chemistry
• Coherent coupling of molecular resonators with a micro-cavity mode
• Quantum Electrodynamical Density-Functional Theory: Bridging Quantum Optics and Electronic-Structure Theory
• Light-matter interaction in the long-wavelength limit: no ground-state without dipole self-energy
• Cavity Born-Oppenheimer Approximation for Correlated Electron-Nuclear-Photon Systems
• Coupled Cluster Theory for Molecular Polaritons: Changing Ground and Excited States
• Time-dependent density functional theory for many-electron systems interacting with cavity photons
• Kohn-Sham Approach to Quantum Electrodynamical Density Functional Theory: Exact Time-Dependent Effective Potentials in Real Space
• Intermolecular interactions in optical cavities: an ab initio QED study
• Cavity-modulated ionization potentials and electron affinities from quantum electrodynamics coupled-cluster theory
• Molecular orbital theory in cavity QED environments
• Time-dependent Kohn-Sham approach to quantum electrodynamics
• Cavity-Born-Oppenheimer Hartree-Fock Ansatz: Light-matter Properties of Strongly Coupled Molecular Ensembles
• Cavity-Altered Thermal Isomerization Rates and Dynamical Resonant Localization in Vibro-Polaritonic Chemistry
• Beyond Cavity Born-Oppenheimer: On Non-Adiabatic Coupling and Effective Ground State Hamiltonians in Vibro-Polaritonic Chemistry
• Variational Lang-Firsov approach plus Møller-Plesset perturbation theory with applications to ab initio polariton chemistry
• Ab-Initio Vibro-Polaritonic Spectra in Strongly Coupled Cavity-Molecule Systems
• Do Molecular Geometries Change Under Vibrational Strong Coupling?
• A quantum chemistry approach to linear vibro-polaritonic IR spectra with perturbative electron-photon correlation
• Cavity-modified electronic interactions in molecular ensembles under vibrational strong coupling: Combined insights from cavity Born-Oppenheimer perturbation and ab initio wave function theories