Siegbahn notation

Siegbahn notation is a way of giving names to different x-ray energy levels. Think of it like giving each level a special nickname so we can talk about them easily.

We start by splitting the x-ray energy levels into groups called "shells". Think of each shell as a layer of an onion. The smallest shell is called K, then we move out to the L, M, N, and O shells.

Each shell can have different energy levels, which we give special nicknames too. For example, the K shell can have two energy levels, which we call K₁ and K₂. The L shell can have three energy levels, which we call L₁, L₂, and L₃.

But we can get even more specific than that. Each energy level within a shell can have a different number of electrons. We count these electrons and put that number in front of the energy level's nickname. So if the K₁ level has one electron and the K₂ level has two electrons, we write them as "1K₁" and "2K₂".

This is really useful because when we observe x-ray spectra, we can see the different energy levels that the atoms in a material have. By using Siegbahn notation, we can easily identify which energy levels are which, and how many electrons are in each one.