Subject: IR halfband widths

From: "Hr. Dr. S. Shapiro" <[email-masked]>
Date: Tue, 03 Oct 2000 15:12:18 +0100

Dear Colleagues;

	I quote from an article published in Spectrochim. Acta 19: 1013 (1963):

	"Band broadening can also result where a complex polyatomic molecule can 
exist in different conformational forms.  If the centers of conformational 
isomerism are ultimately involved in the normal vibration responsible for 
the absorption, it is likely that two separate bands will be resolved, and 
many cases of this kind are known.  However, if centers of conformational 
isomerism are more remote from the atoms primarily involved in the normal 
vibration, the perturbation of the steric change on the band frequency may 
be very small, in which case it will only act to broaden the band.  NO 
EXAMPLES OF SUCH AN EFFECT HAVE YET BEEN POSITIVELY DEMONSTRATED 
...."  [Emphasis by capitalisation added.]

	I would be very interested in hearing from anyone who can supply me with 
references definitively demonstrating conformational IR band broadening of 
the type that, as of 1963, still had not been positively demonstrated.

Thanks in advance to all responders,

S. Shapiro
[email-masked]