# Parity of two body system

1. May 25, 2008

### physics_fun

I'm confused about how parities 'add up'.
(I'm using the shell model of a nucleus)
If you have e.g.a neutron in a d state (so l=2) and one in a p state (l=1), what is the parity of the total system? Do you have to multiply (+1*-1=-1?) or add the l values or something completely different?

2. May 25, 2008

### eys_physics

Hey
The parity $$\pi$$ for a state is $$(-1)^{l}$$ The total parity is
$$\pi_{1}*\pi_{2}$$ or
$$(-1)^{l_{1}+l_{2}}$$

3. May 25, 2008

### physics_fun

Thanks!

4. May 25, 2008

### malawi_glenn

Yes, parities are multiplied.