Zeeman Effects in Complex Spectra at Fields up to 100,000 Gauss

Abstract

A newly constructed electromagnet of the Bitter type has been arranged to give fields up to 100,000 gauss, uniform to 1 percent over a volume of 25 cc. A special type of horizontal arc, with electrodes of salts compressed in silver powder, is operated at 4 amp. and furnishes light transversely to the field to three grating spectrographs, which can be used to cover the range 2000 to 8000A in a single exposure. Plane-polarized components of the light are separated with a 2-inch quartz Rochon prism, and exposures of 5 to 30 minutes give dense spectrograms at resolutions of 100,000 and greater. Plates in the ultraviolet region have been obtained for cerium, columbium, erbium, europium, gadolinium, iron, neodymium, praseodymium, rhodium, ruthenium, thorium, tungsten, and ytterbium. On most of the plates lines of the second and third spectra are more in evidence than those of the first, and air lines are prominent. Typical portions of a rhodium plate at 90,500 and 70,000 gauss are shown, and data are given for a number of cerium, rhodium, and ruthenium lines.