Arc Spectrum of Germanium*†

Abstract

The arc spectrum of germanium has been investigated in the region 1546 A to 11 252 A with concave grating spectrographs and interferometers by the use of various arc and hollow cathode sources. Wavelength measurements supplied by other laboratories are included. The wavelength material has been greatly improved and extended from 184 lines to 475 lines. Of these about 200 visible and infrared lines were found by the development of a special low pressure Ge arc source.An extended analysis of this spectrum has led to 94 new levels and nearly 300 newly classified lines. At present there are 68 even levels belonging to the 4s2 4pnp and 4s2 4pnf configurations and 87 odd levels belonging to the 4s2 4pns, 4s2 4pnd, and 4s4p3 configurations. Improved series limit calculations give the value 63 715±10 cm−1 for the 4s2 4pP212° level of Ge II with respect to the 4s2 4p2 3P0 level of Ge I, corresponding to an ionization potential of 7.899±0.001 volt.