New developments in the field of bremsstrahlung isochromat spectroscopy

Methods and experimental results are reviewed of the bremsstrahlung isochromat spectroscopy (BIS) for electronic structure investigations of solids and compared with other spectroscopic methods of electronic states. Two new BIS methods are described: (1) the BIS by means of an absorption edge spectrometer without a crystal monochromator, and (2) the BIS in the ultraviolet quantum energy range. The application of the different methods is illustrated by means of some examples