  The field of molecular electronics has emerged from efforts to understand
electron propagation through single molecules and to use them in electronic
circuits. Serving as a testbed for advanced theoretical methods, it reveals a
significant discrepancy between the operational time scales of experiments
(static to GHz frequencies) and theoretical models (femtoseconds). Utilizing a
recently developed time-linear nonequilibrium Green's functions formalism, we
model molecular junctions on experimentally accessible timescales. Our study
focuses on the quantum pump effect in a Benzenedithiol molecule connected to
two copper electrodes and coupled with cavity photons. By calculating both
electric and photonic current responses to an ac bias voltage, we observe
pronounced electroluminescence and high harmonic generation in this setup. The
mechanism of the latter effect is more analogous to that from solids than from
isolated molecules, with even harmonics being suppressed or enhanced depending
on the symmetry of the driving field.
