# Energy levels in a potential well

1. Jun 5, 2008

### physmile

I know this question seems very simple which is why its bugging me so much:
Why is the ground state energy not zero?
A simple answer would be greatly appreciated

2. Jun 5, 2008

### torehan

$$\vec{}$$
Energy states are defined with priciple quantum number (n). n= 1,2,3....

$$E_{n}= \frac{-me^{4}}{2h^{2}n^{2}}$$

"Ground state" means 1st term in serie of "n" and it's 1.

You may ask, why doesn't "n" start from zero? When you put 0 for n, energy goes to infinite and that mean electron separated from atom. That's why n doesn't start from zero.

And finally your question, there is allways a energy in an atom because of the Coloumb potential. The energy never been zero.

3. Jun 5, 2008

### 2Tesla

Only changes in energy are physical. You can define the ground state of any particular system to have zero energy.

4. Jun 5, 2008

### physmile

Thank you very much for your help torehan!