Why doesn't N2 absorb infrared radiation Watch
- Thread Starter
- 07-10-2016 15:08
- 07-10-2016 15:11
(Original post by AngryRedhead)
- 07-10-2016 18:04
I would assume because of the triple bond present in this diatomic molecule is too high for a photon of infra-red to overcome?
It isn't really something you can understand at A Level.
The transition moment for a transition between an upper and lower states (for which the vibrational wave functions are and respectively) is:
Where is the dipole moment operator. The only thing you really need to worry about is that a homonuclear diatomic has no dipole moment no matter how the bond length changes, so this integral is zero and we call homonuclear diatomics IR inactive.
Basically there has to be a change in dipole moment for IR to be absorbed by a molecule, which can never happen for a homonuclear diatomic.Last edited by alow; 07-10-2016 at 18:09.