Absorption Spectra of Mercury, Cadmium and Zinc at High Pressure*

Abstract

Absorption spectra of mercury, cadmium, and zinc vapors have been photographed with a quartz spectrograph using absorption cells containing vapor at pressures ranging up to several atmospheres.The spectra are characterized by wide regions of continuous absorption and series of flutings and diffuse bands. Some of these have been previously observed in emission.The flutings may be interpreted as poorly resolved band systems of diatomic molecules in which the excited electronic state is much more stable than the normal state. It is possible to account for the long duration of fluorescence by assuming that first the molecule is raised to a high vibration state by absorption and that consequently by a collision of the second kind it drops to a low vibration state having a very small emission probability.