0000000000319262
AUTHOR
Horst Schmidt-böcking
The Stern-Gerlach experiment revisited
The Stern-Gerlach-Experiment (SGE) of 1922 is a seminal benchmark experiment of quantum physics providing evidence for several fundamental properties of quantum systems. Based on today's knowledge we illustrate the different benchmark results of the SGE for the development of modern quantum physics and chemistry. The SGE provided the first direct experimental evidence for angular momentum quantization in the quantum world and thus also for the existence of directional quantization of all angular momenta in the process of measurement. It measured for the first time a ground state property of an atom, it produced for the first time a `spin-polarized' atomic beam, it almost revealed the electr…
Time-of-flight photoemission electron microscopy – a new way to chemical surface analysis
Abstract The time structure of synchrotron radiation at BESSY I (Berlin) was utilised to operate a photoemission electron microscope in the time-of-flight mode. The electrons that are emitted from the sample surface with different energies are dispersed in a drift tube subsequent to the imaging optics. Two ways of fast image detection have been explored, a fast gated intensified CCD camera (800 ps gate time) and a special counting electronics in combination with a 3D (x,y,t)-resolving delay line detector ( time resolution ps). The latter device has a lateral resolution of about 50 μm in the image plane being equivalent to 1000 pixels along the image diagonal. An energy resolution of 400 meV…
Electron-TOF-analyser for complete momentum analysis in photoemission from surfaces
Abstract We present a new method for momentum-selective imaging by means of a time-of-flight (TOF) technique. The instrument employs a time- and space-resolving delayline detector in combination with a parabolic electrostatic field and a drift space. We use this kind of spectrometer, to raise the efficiency of experiments, which are total momentum resolved. The main difference to conventional photoemission experiments using a rotatable spectrometer is the simultaneous detection of all emitted photoelectrons. In addition to this feature, the angular distribution should be directly visible, to observe solid state symmetries. In order to facilitate these requirements, we use a delayline detect…