In situ Measurements of Metallic Surface and Beverage Using Photoemission Yield Spectroscopy in Air

An open counter is a unique detector that can detect and count a small number of low energy photoelectrons, and can be operated in air under atmospheric pressure. Therefore, photoemission yield measurements can be performed in air by using photoemission yield spectroscopy in air (PYSA), which employs an open counter as a detector. A PYSA measurement is carried out as follows: UV-rays emitted from a deuterium lamp are monochromatized and focused on a sample surface. The number of emitted photoelectrons from the sample is counted by the open counter in air. Thus, in situ measurements of the electronic structure under ambient conditions can be performed by collecting the photoemission yield. We have demonstrated the applicability of PYSA for characterizing the electronic properties under ambient conditions. In this paper, two types of example of the use of PYSA are introduced. One involves measurements of changes in the work function of Pt, Pd and Au surfaces during the desorption of oxygen; the other involves characterization of the electronic properties of catechins in water.