Multiple orbital effects in laser-induced electron diffraction of aligned molecules

Photoelectron angular distributions (PADs) resulting from 800 and 1300 nm strong-field ionization of impulsively aligned CF3I molecules were analyzed using time-dependent density functional theory (TDDFT). The normalized difference between the PADs for aligned and antialigned molecules displays large modulations in the high-energy recollision plateau that are assigned to the diffraction of backscattered photoelectrons. The TDDFT calculations reveal that, in spite of their 2.6 eV energy difference, ionization from the HOMO-1 orbital contributes to the diffraction pattern on the same footing as ionization from the doubly degenerate HOMO orbital.
F.K. would like to acknowledge funding under European Community’s Seventh Framework Programme under Contract No. ITN-2008-238362 (ATTOFEL). P.W., B.F., U.D.G., and A.R. acknowledge financial support from the European Research Council (ERC-2015-AdG-694097), Grupos Consolidados (IT578-13), and European Unions Horizon 2020 Research and Innovation program under Grant Agreement No. 676580 (NOMAD). A.R. would like to thank the Deutsche Forschungsgemeinschaft, Schwerpunktprogramm 1840 (SPP 1840 QUTIF project). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 674960 (ASPIRE).