The latter can also measure the resonant inverse photoemission spectroscopy. However, some companies are now selling products that allow photoemission in air. His work included field electron emission and photoemission studies of surfaces. A photoemission electron microscope is a parallel imaging instrument. The equivalent technique for electron states is inverse photoemission. Photoemission spectra are also measured using synchrotron radiation sources. Photoemission spectroscopy also could provide information on the HTS symmetry. The photoemission rate is influenced by the local excitation level of the sample. Angle resolved photoemission spectroscopy (ARPES) is a powerful tool for structure analysis. This method is referred to as high-energy X-ray photoemission spectroscopy (HAXPES).