“Anomalous” Photoelectric Effect in the Ultrafast Electron Diffraction Method

Abstract

Electron-pulse probing of fast laser-induced processes has allowed the direct observation of the structural dynamics in matter with a high spatiotemporal resolution. A thin gold film has appeared to be a convenient photocathode, and photoelectron emission has been induced by femtosecond ultraviolet radiation with a photon energy of about 4.65–4.75 eV (in particular, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbar $$\\end{document}ω \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\cong $$\\end{document} 4.65 eV for the third harmonic of the Ti:sapphire laser). For the linear photoelectric effect, this energy contradicts the reference work function WAu\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\cong $$\\end{document} 5.1–5.3 eV of pure metal. Reasons for such contradiction have been analyzed and good agreement with experimental data has been reached with a model proposed for the generation of photoelectron pulses.