He became a docent in 1912, and in 1914 he became a professor of chemistry at the Royal Agricultural College (Landbohøjskolen) in Copenhagen, as successor of Odin Tidemand Christensen.
The subject of the papers is the kinetic and quantum theories through absorption measurements in the infrared to elucidate the constitution and the optical and thermal properties of matter.
He advanced the studies of specific heat that had been made for solids by Albert Einstein, Walther Nernst, and Lindemann.
Using the quantum hypothesis, the infrared absorption spectra of water vapor were shown to link to the line broadening caused by molecular rotational frequencies that vary discontinuously and to radiating atoms that do not rotate.
[6][7] Between 1916 and 1926 he investigated the properties of electrolytic solutions in regards to their dissociation and association in German journals like Z. anorg.