Photoelectron emission (PE) discloses the transfer of electrons on scratched metal surfaces

What is it about?

PE occurs when photons are absorbed by electrons, leading to the release of these photon-absorbing electrons from the surface. For real iron surfaces, however, little electron emission is observed at temperatures close to room temperature. This is caused by the effect of the surface overlayer. In this study samples were scratched in air, water, methanol, ethanol, acetone, benzene, and cyclohexane. The PE measurement was carried out during heating the sample under light irradiation. PE quantum yield represented by the number of emitted electrons per an incident photon of the light was obtained as a function of temperature, leading to the activation energy for the quantum　yield. This activation energy differed greatly between the environments. It was shown that this activation energy has a close relation to the intensity of PE for the environments.

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Why is it important?

Much attention has been given to studying the role of charge transfer and electronic excitation in the overlayers of real metallic surfaces in relation to various problems in tribology, adhesion, corrosion, and so on. However, little is known about the behavior of electrons in these superficial layers, owing to the difficulties associated with experimental measurements of such electrons. We developed a non-vacuum-based experimental system consisting of an electron measuring chamber filled with a flowing Q gas (a mixture of 99% helium and 1 % isobutene vapor) at atmospheric pressure, an electron counting system, a light irradiation system, and a heating system.

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