Sturmian approach to the study of photoionization of atoms and molecules

In this presentation we study the photoionization of atoms and molecules using ultrashort laser pulses, solving the time-independent Schr\"{o}dinger equation (TISE) in a first order perturbation theory. The interaction laser-matter is described with the dipolar operator in the velocity gauge. Generalized Sturmian functions [1] are used to solve the driven equation for a scattering wave function which includes all the information about the ionization problem. For the atomic case, we study the photoionization of He atom using the Hermann-Skillman potential together with the one-active electron approximation. For molecular systems (CH$_{4}$ in this work), we use first a spherically symmetric potential U$_{i}$(r) [2], and then a more realistic potential that includes all the nuclei and other electrons interaction, as in [2]. For each molecular orbital we use Moccia's wave functions [3], solve the TISE with an initial molecular orbital i of the ground state and extract the corresponding photoionization cross sections. For both atomic and molecular systems we compare our results with previous calculations and available experimental data. \\[4pt] [1] D. M. Mitnik et al, Comp. Phys. Comm. 182, 1145 (2011); Gasaneo et al, submitted to Adv. Quantum Chem (2013)\\[0pt] [2] L Fernandez-Menchero and S Otranto, Phys. Rev. A 82 022712 (2010)\\[0pt] [3] R Moccia, J. Chem. Phys. 40 2164. (1964)