Albert Einstein was the first to explain this phenomenon in 1905, when he spoke of "light quanta" (known today as photons). In tiny fractions of a second, they "jump" into another state when light falls on a material. This takes place so quickly that until now it has mostly been regarded as a sudden change of state. However, with the help of sophisticated experiments and calculations, the Vienna University of Technology has succeeded for the first time in precisely measuring the duration of this famous photoelectric effect. The researchers published the results in the scientific journal "Nature".
The change into another state takes place within attosecond, or billionths of a billionth of a second. In the initial step, the photoelectric effect was measured in the case of simply structured helium atoms. The results served as the reference scale for determining the effect for iodine atoms. Finally, a tungsten surface was examined.
The duration of the photoemission process depends on the initial state of the electrons. It ranges from 100 attoseconds for electronics in the inner shells of the tungsten atoms to 47 attoseconds for conduction band electrons which pass the finish line faster on average. The measurements were carried out at the Max Planck Institute for Quantum Optics in Garching, Germany.