title: Role of tunnel ionization in high harmonic generation from substituted benzenes.
abstract: We theoretically study high-harmonic generation in toluene, ortho-xylene and fluorobenzene driven by a 1.8 μm ultrashort pulse. We find that the chemical substitutions have a strong influence on the amplitude and phase of the emission from the highest occupied molecular orbital, despite having a small influence on the orbital itself. We show that this influence is due to the tunnel ionization step, which depends critically on the sign and amplitude of the asymptotic part of the wave function. We discuss how these effects would manifest in phase-sensitive high-harmonic generation spectroscopy experiments.
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK. d.austin@imperial.ac.uk.
authors.forename: Dane R
authors.initials: DR
authors.lastname: Austin
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK. d.austin@imperial.ac.uk.
authors.forename: Felicity
authors.initials: F
authors.lastname: McGrath
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK. d.austin@imperial.ac.uk.
authors.forename: Lukas
authors.initials: L
authors.lastname: Miseikis
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK. d.austin@imperial.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Wood
authors.affiliation: Department of Physics, Philipps-Universität Marburg, Renthof 5, D-35032 Marburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Hawkins
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK. d.austin@imperial.ac.uk.
authors.forename: Allan S
authors.initials: AS
authors.lastname: Johnson
authors.affiliation: Department of Chemistry, Imperial College London, London, UK.
authors.forename: Morgane
authors.initials: M
authors.lastname: Vacher
authors.affiliation: Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin, Germany.
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Mašín
authors.affiliation: Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin, Germany.
authors.forename: Alex
authors.initials: A
authors.lastname: Harvey
authors.affiliation: Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin, Germany.
authors.forename: Misha
authors.initials: M
authors.lastname: Ivanov
authors.affiliation: Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Smirnova
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK. d.austin@imperial.ac.uk.
authors.forename: Jon P
authors.initials: JP
authors.lastname: Marangos