# Homework Help: What are the allowed transitions in the pure rotational spectra of CO2 molecule?

1. Sep 21, 2010

### Shivpal

I know that the selection rule is :
$$\Delta$$J = +/- 1

but our prof said that according to some quantum mechanical calculations the odd values of J are not allowed. So, the allowed transitions are :
J 0 <-> 1 ; 2 <-> 3 ; 4 <-> 5..... as the odd(1,3,5..) states will not be populated(hence contradicting his own statement).... and no transitions as J 1 -> 2 ; 3 -> 4 ....

I raised the question in the class but he seemed a bit more confused after my question.

Can anyone confirm the authentication of his statements. And Please tell me what is right and what is wrong. Thanx.

2. Sep 22, 2010

### Awatarn

3. Sep 24, 2010

### Shivpal

...I checked everything on the internet (starting with wiki), and then asked the question here...by the way i got the answer...thanks for showing concern...