| 释义 |
Pfund Physics.|fʊnt|
The name of A. Herman Pfund (1879–1949), U.S. physicist, used attrib. to designate a series of lines in the infra-red part of the spectrum of atomic hydrogen, with wave numbers represented by R(1/52 - 1/m2) (where R is the Rydberg constant and m = 6, 7, {ddd}), of which the first line has a wavelength of 7·46 micrometres and the series limit is at 2·28 micrometres.
1934H. L. Brose tr. Sommerfeld's Atomic Struct. & Spectral Lines (ed. 3) ii. 73 A. H. Pfund found an infra-red line belonging to hydrogen at λ = 7·40µ, which is the first member of a ‘Pfund series’ and corresponds to n = 5, m = 6. 1970D. W. Tenquist et al. University Optics II. ii. 43 Lines in the infra-red part of the spectrum are caused by transitions terminating at n = 3 (Paschen series), n = 4 (Brackett series) and n = 5 (Pfund series). |