Effect of multiorbital contributions to strong-field ionization of benzene derivatives

Strong-field ionization of benzene, fluorobenzene, benzonitrile, and 1-chloro-2-fluorobenzene is studied within the framework of real-space and real-time time-dependent density functional theory. Analysis of the ionization rates as a function of the molecule orientation reveals a significant contribution from multiple inner Kohn-Sham orbitals that depends on the electronic structure and on the orbital symmetries of the molecule, as well as on the polarization and intensity of the external laser field. Calculated photoelectron angular distributions at different molecular orientations and in response to laser fields with different degrees of ellipticity further demonstrate the spatial dependency of the orbital ionization rates.