Ftir

[ChemSiddiqui]

Hi all,

 

I was just wondering and was infact a bit curious about a question thats was bring put forward to me. In FTIR, N2 is used to take the background right and it is supposed to have no absorption peak becuase it is not a dipole but still the N2 show absorption peak....! I don't know how that can be. May be there is a reason that the in N2 molecule bond if not vibrate but does rotate that show the absorption peak.

 

I have no clue....any help????!

[John Cuthber]

N2 doesn't have any absorbtion in the IR region. If you have a peak, it isn't N2.

[ChemSiddiqui]

No John, I tried the experiment my self and do get some absorption peak. I was quite confused. But now i am thinking that it maybe that the cell i used to put N2 into had been used to put some CO in before so maybe the N2 was mixed with some traces of CO when I put N2 in the cell and it showed some absorption peak

[John Cuthber]

No John, I tried the experiment my self and do get some absorption peak.

You may get a apeak but trust me, N2 really doesn't absorb IR. As I said, if you have an absorbtion, it isn't due to N2.

Is the peak at the right wavelength for CO?

[ChemSiddiqui]

I know the peak can't be N2 because N2 doesn't have a dipole hence no absorption peak. The wavenumber matches the co as well as the peak shape so I think my suspicion that there were some traces of CO in the cell.

 

Thanks for your interest and help though!