Quantum-electrodynamical time-dependent density functional theory description of molecules in optical cavities

Abstract

A quantum electrodynamical time-dependent density functional theory framework is applied to describe strongly coupled light--matter interactions in cavity environments. The formalism utilizes a tensor product approach, coupling real-space electronic wave functions with Fock space photonic states. Various molecular systems serve as test cases to examine how coupling parameters and cavity frequencies affect molecular geometry, polaritonic spectra, and intermolecular binding.

Figures (13)

• Figure 1: Comparison of PES calculated using QED-DFT-TP with PN-QED-FCI and PN-QED-CASCI. All graphs use $\lambda=0.05$ and $\omega=0.121$. The left graph uses $N_F=1$, while the right compares PN-QED-CASCI $N_F=1$ and $N_F=10$ to QED-DFT-TP.
• Figure 2:
• Figure 3:
• Figure 4: Left: Dependence of the polaritonic energies on $\lambda$. The upper and lower curves show the energies of the upper and lower polaritons; the middle curve shows the energy dependence due to the diamagnetic term without coupling to the light. Right: Upper and lower polaritonic energies after subtracting the diamagnetic term's effect. The parameters used for the calculation are $N_{x}=N_{y}=N_{z}=71$, $h=0.3$ a.u. grid spacing, $\Delta t=0.01$ a.u. and the number of time steps is 100000.
• Figure 5: A comparison of the polaritonic energies of BH$_3$ using QED-TDDFT and QED-FCI. The QED-TDDFT graph was shifted to fit it into the same scale. The graph begins at $\lambda=0.02$ because for lower coupling strengths we do not resolve a splitting in QED-TDDFT. The same TDDFT parameters were used as in Fig. \ref{['fig:4']}.