# A Spectrum

1. Apr 23, 2005

### Haftred

Where can I find the different energy levels (in eV) for Li (2+). I can't seem to find it in my textbook or on the internet.

2. Apr 24, 2005

### mathman

3. Apr 25, 2005

### Jayse_83

You could try quantum mechanic solutions ... not for the faint hearted though...
If you know the number of electrons in Li you have to begin filling shells using the quantum numbers n,l and Ml .. which each have restrictions in their values. You keep filling the electrons in the shells (dont forget spins!) until you are left with an unfilled shell. Excitation energy levels occur when the last electron is placed in the higher energy levels and not the next available level.
Have fun

4. Apr 25, 2005

### inha

that's way too much work considering that the levels are well tabulated.

5. Apr 25, 2005

### SpaceTiger

Staff Emeritus
Li2+ is just a hydrogen-like ion, I believe, so its energy levels are given simply by:

$$E=13.6\frac{Z^2}{n^2}\ eV=\frac{122.4}{n^2}\ eV$$

This isn't exact because it neglects fine structure and hyperfine structure, but for most purposes, the above should suffice.

Last edited: Apr 25, 2005