# Hydrogenic atom

1. Feb 22, 2009

### eman2009

1. The problem statement, all variables and given/known data

using first-order perturbation theory ,estimate the correction to the ground state energy of a hydrogenic atom due to the finite size of the nucleus, assume it's spherical nucleus.

2. Relevant equations

you can employ the fact that the electrostatic potential fi
fi=Ze/R(3/2-r^/2R^ ,if r<R

=Ze/r ,if r>R

fi is elctrostatic potential

3. The attempt at a solution

2. Feb 23, 2009

### orthovector

think Bohr radius $$A_o =$$ Bohr radius

3. Feb 23, 2009

### malawi_glenn

can you please write down the potential "fi" more clear?

is it

$$\phi = \frac{Ze(3/2 -r^2/(2R^2))}{R}$$ ?? or

$$\phi = \frac{Ze}{R(3/2 -r^2/(2R^2)}$$

Also show attempt to solution, you have to show some effort in order to get help. Read the rules of this forum.

4. Feb 23, 2009

### eman2009

sorry
the second one is
fi=Ze/r only
and the first one is correct
there is two equation for fi .....

i tryed to treat (fi) as (V) ,my question is how i can applay the perturbation theory in the same time using radial equation ? if i use perturbation theory what is (ebsay)
is it
1/(squarbi a^3).e^-r/a
for ground state
thanks

Last edited: Feb 23, 2009
5. Feb 23, 2009