Polar diatomic molecules in optical cavities: Photon scaling, rotational effects, and comparison with classical fields.

We address topics related to molecules coupled to quantum radiation. The formalism of light-matter interaction is different for classical and quantum fields, but some analogies remain, such as the formation of light induced crossings. We show that under particular circumstances, the molecular dynamics under quantum or classical fields produce similar results, as long as the radiation is prepared as a Fock state and far from ultra-strong coupling regimes.

Revealing the Presence of Potential Crossings in Diatomics Induced by Quantum Cavity Radiation.

We propose an experiment to find evidence of the formation of light-induced crossings provoked by cavity quantum radiation on simple molecules by using state-of-the-art optical cavities, molecular beams, pump-probe laser schemes, and velocity mapping detectors for fragmentation. The procedure is based on prompt excitation and subsequent dissociation in a three-state scheme of a polar diatomic molecule, with two ^{1}Σ states (ground and first excited) coupled first by the UV pump laser and then by the cavity radiation, and a third fully dissociative state ^{1}Π coupled through the delayed UV/V probe laser. The observed enhancement of photodissociation yields in the ^{1}Π channel at given time delays between the pump and probe lasers unambiguously indicates the formation of a light-induced crossing between the two ^{1}Σ field-dressed potential energy curves of the molecule.

Entangled Photonic-Nuclear Molecular Dynamics of LiF in Quantum Optical Cavities.

The quantum photodynamics of a simple diatomic molecule with a permanent dipole immersed within an optical cavity containing a quantized radiation field is studied in detail. The chosen molecule under study, lithium fluoride (LiF), is characterized by the presence of an avoided crossing between the two lowest Σ potential energy curves (covalent-ionic diabatic crossing). Without field, after prompt excitation from the ground state 1 Σ, the excited nuclear wave packet moves back and forth in the upper 2 Σ state, but in the proximity of the avoided crossing, the nonadiabatic coupling transfers part of the nuclear wave packet to the lower 1 Σ state, which eventually leads to dissociation.

Autoionization of molecular hydrogen: where do the Fano lineshapes go?

Atomic autoionization following photoabsorption is a typical example of quantum interferences governed by electron-electron correlation. Coherence between direct photoionization and autoionization paths results in "Fano profiles", widely explored in atoms in the last 60 years. The advent of femto- and attosecond laser technology made time-resolved images of the delayed electron ejection in autoionization accessible, leading to the reemergence of such studies in atomic systems.