Pfund series
/ˈfʊnt ˌsɪərɪz/ /ˈfʊnd ˌsɪərɪz/Physics
noun
A series of lines in the infrared part of the spectrum of atomic hydrogen, with wave numbers represented by R(1/52 − 1/m 2) (where R is the Rydberg constant and m = 6, 7,…), of which the first line has a wavelength of 7.46 micrometres and the series limit is at 2.28 micrometres.
Origin
1930s; earliest use found in Henry Brose (b. 1890). From the name of A. Herman Pfund, U.S. physicist, who discovered the phenomena + series, after German Pfund-Serie.