On the Spectrum of Cadmium in the Inactive Gases

J. N. Collie, H. E. Watson
1918 Proceedings of the Royal Society A  
In cases where with sufficient accuracy whirling speeds higher than the second may be neglected we have, in the foregoing notation, J L + -J -= ft] + & 2 + c3 + ••• fll £ 1 % " and n } q the sum of all the second order determinants about the principal diagonal. fii and n 2 may thence be determined. During the last few years some attention has been paid to the spectrum of gases in the neighbourhood of the cathode discharge, and, therefore, it is thought to be worth while putting on record some
more » ... periments that were made about ten years ago, but which were not considered at the time to be of sufficient importance to be published, as they led to no definite conclusion. One of the authors* had noticed that, in a vacuum tube containing helium and mercury vapour, the orange mercury line 6152 appeared very brightly, although it is not usually seen at all in a tube containing a diatomic gas. Continuing this line of research, other metals were experimented on, with those metals as electrodes. It was at once noted that in many cases, at comparatively high pressures and low current densities, lines in the spectrum of the metals composing the electrodes were visible in the neighbourhood of the cathode, and often in other parts of the tube as well. The following experiments were made, with the view of studying more thoroughly this effect. Cadmium was the metal chosen, on account of the ease with which the metallic spectrum was produced, and also because the cadmium bright lines extend over a considerable portion of the visible spectrum. Other metals that behave in fi similar manner are zinc, magnesium, lead, bismuth. The gases experimented with were helium, neon, argon, and xenon.
doi:10.1098/rspa.1918.0053 fatcat:lxt6oomy2nhqnglm6vuzjej2qu