Einstein, Specific Heats, and Residual Rays: The History of a Retracted Paper

Abstract

Towards the end of 1911 Albert Einstein submitted a paper to the Annalen der Physik with the title “Zur Theorie der Reststrahlen” (“On the Theory of Residual Rays”). It was inspired by the experimental work of the Berlin experimentalist Heinrich Rubens and his collaborators on the optical properties of solids in the far infrared. Some substances, for instance NaCl, exhibit selective reflection of infrared radiation: they strongly reflect radiation of certain characteristic wavelengths, whereas they are transparent for other infrared wavelengths. The reflected rays are known as residual rays, and Rubens had determined the wavelengths of the residual rays for a number of substances. Because the frequencies of the residual rays were thought to be connected with characteristic frequencies of the substances that produce them, their determination was important for theories in which proper frequencies of solids played a role, in particular the quantum theory of specific heats first developed by Einstein.

I am grateful to the Albert Einstein Archives of the Hebrew University of Jerusalem for permission to quote from Einstein’s letters.