Pound series

Term scheme of the hydrogen atom

The pound series is the sequence of spectral lines in the spectrum of the hydrogen atom whose lower energy level is in the O-shell .

Other series are the Lyman , Balmer (see also the versions there), Brackett , Paschen and Humphreys series .

spectrum

The spectral lines of the Pfund series are all in the infrared range of light. They were discovered in 1924 by the American physicist August Herman Pfund (1879–1949).

Mathematical description

The wave numbers of the spectral lines are given by the formula

${\displaystyle {\tilde {\nu }}=R_{\infty }\left({1 \over 5^{2}}-{1 \over n^{2}}\right)}$

is given, where

${\displaystyle R_{\infty }=1{,}0973731534\cdot 10^{7}\,{\mathrm {m^{-1}} }}$

is Rydberg's constant and n is an integer greater than 5.

From the wave number can be determined by the relationship

${\displaystyle \lambda ={\frac {1}{\tilde {\nu }}}}$

calculate the wavelength. Out

${\displaystyle E={\tilde {\nu }}\cdot c\cdot h}$

results in the energy of the corresponding photon .

See also

• Moseley's law

literature

• AH books: The emission of nitrogen and hydrogen in infrared. In: J. Opt. Soc. At the. 9, No. 3, 1924, pp. 193-196 ( doi : 10.1364 / JOSA.9.000193 ).