Laser-induced resonances in molecular dissociation in intense fields

Quantum-classical nonadiabatic dynamics of Floquet driven systems

We develop a trajectory-based approach for excited-state molecular dynamics simulations of systems subject to an external periodic drive. We combine the exact-factorization formalism, allowing us to treat electron-nuclear systems in nonadiabatic regimes, with the Floquet formalism for time-periodic processes. The theory is developed starting with the molecular time-dependent Schrödinger equation with the inclusion of an external periodic drive that couples to the system dipole moment. With the support of the Floquet formalism, quantum dynamics is approximated by combining classical-like, trajectory-based, nuclear evolution with electronic dynamics represented in the Floquet basis. The resulting algorithm, which is an extension of the coupled-trajectory mixed quantum-classical scheme for periodically driven systems, is applied to a model study, exactly solvable, with different field intensities.

Molecules in high-intensity laser fields

The separability of a dressed molecule, a composite molecule + quantized radiation field system, at high field intensities is examined. Various forms of the Hamiltonian describing the dressed molecule are reviewed and are used to assess the zeroth-order separability of the dressed system. A new high-order adiabatic separation between the strongly coupled quantized field and molecular subsystems is derived. Qualitative manifestations of laser-induced molecular structures are discussed within this high-order adiabatic representation. Key words: dynamics, dressed molecule, intense laser field, adiabatic separation, laser-induced molecular structure.