On Fluorescence Radiation of Nitrogen

Abstract

In Wood's resonance spectra of iodine vapor, Lenz [1] succeeded in measuring some fundamental constants of the iodine molecule. In an attempt to apply the same methods to other gases, especially hydrogen and nitrogen, some observations have been made upon the fluorescence radiation of the nitrogen ion. These are reported in the present paper. The main difficulty in exciting fluorescence in hydrogen and nitrogen is that these gases absorb only wave-lengths of the extreme ultra-violet. We cannot, therefore, put a window of any material in the path of the exciting light. Instead, the light source, e.g., a condensed spark, must be put into the same bulb with the gas. Further, the pressure of the gas must be as low as a few tenths of a millimeter, in order to prevent the extinction or change of the fluorescence because of the collisions of the excited molecules. In the present experiments disturbing electric currents (glow discharges) were prevented by three different means: (1) by enclosing the condensed spark in a glass tube containing one small lateral opening out of which the light could come, (2) by meaus of a Faraday cage with a small opening into which the light could shine and there excite the fluorescence, (3) by a strong magnetic field parallel to the spark discharge.