# Applying Bohr's Hydrogen model to a He ion

1. Nov 10, 2004

### MaximumTaco

Hey ppl,

I was wondering, with a singly ionised He atom, can we apply the Bohr model, eg E = 13.6eV/n^2, to find the energy of the excited states? How would i go about that?

2. Nov 10, 2004

### dextercioby

Nglecting all relativistic effects,u could aplly the formula,but with the restriction that the minimum energy is $$13.6*4=54.4$$ eV.which comes from the fact that for Helium ions $$Z=2$$.

3. Nov 12, 2004

### Orion1

Beta Battle...

$$1s^1$$ ground state:
$$E_{1s^1}(Z,n) = \frac{(13.6ev)Z_n^2}{n^2}$$

$$E_{1s^1}(Z,n) = \frac{\alpha^2 M_e c^2 Z_n^2}{2qn^2} = \frac{M_e}{2q} \left( \frac{\alpha c Z_n}{n} \right)^2$$

$$E_{1s^1}(Z,n) = \frac{M_e}{2q} \left( \frac{\alpha c Z_n}{n} \right)^2$$

This equation seems to work for ALL beta $$1s^1$$ states.

Last edited: Nov 12, 2004