Absolute timing of the photoelectric effect

Journal: Nature

Published: 2018-09-19

DOI: 10.1038/s41586-018-0503-6

Affiliations: 4

Authors: 17

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Research Highlight

Photoelectric effect timed by atomic clock

© Universal Images Group/Getty

© Universal Images Group/Getty

An atomic stopwatch has clocked the photoelectric effect to within a few billionths of a billionth of a second.

The photoelectric effect, for which Albert Einstein was awarded his Nobel prize, occurs when a metal absorbs high-energy light and releases an electron. The reaction is so rapid that only the direction and energy of escaping electrons have been accurately measured, until now.

A team that included researchers from the Technological University of Munich stuck iodine atoms onto a tungsten crystal and hit them with X-rays. Iodine atoms react extremely quickly to X-rays so served as a stopwatch for the moment the X-rays hit the crystal’s surface, while a laser pulsing above the crystal measured the arrival time of the escaping tungsten electron. This enabled the researchers to calculate the photoelectric effect duration with attosecond (10−18 second) accuracy, and they observed tungsten generate photoelectrons in about 40 attoseconds.

Understanding photochemical reactions on different surfaces could help improve the efficiency of harvesting solar energy.

Supported content

  1. Nature 561, 374–377 (2018). doi: 10.1038/s41586-018-0503-6
Institutions FC
TUM Department of Physics, Germany 0.62
Institute for Theoretical Physics (ITP), TU Wien, Austria 0.18
Max Planck Institute of Quantum Optics (MPI MPQ), Germany 0.15
Helmholtz-Zentrum Berlin for Materials and Energy (HZB), Germany 0.06

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