# Energy Levels According To Second-Order Perturbation Theory

1. Oct 17, 2012

### JordanGo

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

If E1≠E2≠E3, what are the new energy levels according to the second-order perturbation theory?

2. Relevant equations

H' =
α(0 1 0)
(1 0 1)
(0 1 0)

ψ1=
(1)
(0)
(0)
ψ2=
(0)
(1)
(0)
ψ3=
(0)
(0)
(1)

Second order perturbation theory:
$E^{o}_{n}^{2}=\sum(<\Psi_{n}^{o}|H'|\Psi_{o}^{0}>)^{2}/(E_{0}-E_{n})$

3. The attempt at a solution
I do not know how to obtain the energies of the unperturbed state, nor the functions ψ, can someone help me?

2. Oct 20, 2012

### gabbagabbahey

Can you post the entire problem statement as it was given to you, verbatim (word for word)? It makes no sense to ask for the "new" energy levels without first giving some indication of what the "old" ones are, either directly, or with some context.