Moseley's law

Moseley's law is an empirical law concerning the characteristic electromagnetic spectrum that is emitted or absorbed by atoms.

Using x-ray diffraction techniques in the 1920's, Henry Moseley found that the most intense short-wavelength line in the x-ray spectrum of a particular element was related to the elements atomic number, $Z$ . Moseley found that this relationship could be expressed by a simple formula, later called Moseley's Law.

$f = k_1 \cdot (Z + k_2)$

where:

$f \$ is the frequency of the main x-ray emmission line

$k_1 \$ and $k_2 \$ are constants that depend on the type of line

For example, the values for $k_1 \$ and $k_2 \$ are the same for all $K α$ lines (in Siegbahn notation), so the formula can be rewritten thus:

$f = (2.48*10^{15}) \cdot (Z - 1)$

Moseley's law

See also: Moseley's law, 1920's, Atom, Electromagnetic spectrum, Henry Moseley, Siegbahn notation, Wavelength, X-ray