# Moseley's law and value of effective nuclear charge

It's given in my book that $$\sqrt{\nu}=\sqrt{RC\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)}(Z-b)$$

The above equation is called Moseley's law

$\nu$ is the frequency of X-ray emitted.

$Z$is the atomic number of metal ewhivch is used as the emitter.

$R$ is the Rydberg constant.

$C$ is the velocity of light.

$a,b$ are constants.

How can I find the value of $b$ (for example, what will be the value of $b$ for $k_{\beta}$ line?) It's given that $(Z-b)$ is the effective nuclear charge.

• Why did this get a vote to close as homework? It is obviously not homework. – John Rennie Feb 10 '16 at 7:14
• I don't think there is any easy way to calculate $b$. You would need to calculate the electronic structure of the atom to work out the screening. – John Rennie Feb 10 '16 at 7:15
• It might be useful to mention what some of these variables are, for those who are less than familiar with the field. – Kyle Kanos Feb 11 '16 at 11:12