The arc spectrum of nitrogen has been quite completely excited and measured in the region 8800-3400A with a low voltage arc in a mixture of helium and nitrogen. The process of excitation is probably a two step process: the first being the dissociation of nitrogen molecules into neutral atoms by impacts of the second kind with metastable helium atoms and the second, being the excitation of neutral nitrogen atoms by second impacts with metastable helium atoms. A complete list of wave-lengths is given and the classifications of the lines designated as far as they are known. A considerable number of new lines have been classified.

• Received 24 April 1929

DOI:https://doi.org/10.1103/PhysRev.34.409