Wavenumber
From Citizendium, the Citizens' Compendium
In spectroscopy, the wavenumber indicates the number of EM waves that would fit in a unit of length. The normal units for wavenumbers are inverse centimeters cm-1. A different name for this unit is kayser (after Heinrich Kayser). Light with a wavelength of 500 nm (green) has a wavenumber of 20,000 cm-1 or 20 kK. Photon energy and frequency are proportional to wavenumber: 10 kK corresponds to 1.24 eV.
Historically, wavenumbers were introduced by Janne Rydberg in the 1880's in his analyses of atomic spectra.
Wavenumbers (
), wavelength (
), and frequency (
) are related:
![v' [cm^{-1}] = \frac{1}{\lambda [cm]} = \frac{v [sec^{-1}]}{(c \frac{m}{sec}) (100 \frac{cm}{m})}](/images/math/4/0/6/406c7338eb5cd2bfe07b9ec5e4e34b0a.png)
