Subject: Re: CCL:G:MK, CHELP, and CHELPG in G94 (2): Dipole

From: Jeremy R Greenwood <[email-masked]>
Date: Sun, 16 Feb 1997 18:59:43 +1100 (EST)

Pablo Vitoria Garcia wrote:

> Hi,

> Another question related to the previous one.
> Does it make any sense to constrain the ESP calculated charges to fit the 
> dipole moment for CHARGED molecules?
> I am not sure about it, since the dipole moment value depends on the 
> choice of origin for non-neutral molecules.

No answer to your question, but while we're on the subject:

I'm keen to find ways of interpreting dipole moment of a series of 
anions, in conjunction with looking at the way a series of carboxylate
bioisosteres interact with a charged or strongly polar receptor of
unknown structure. I know the *value* depends on the choice of origin, 
but what about the *direction* of the dipole vector? Can this be used 
as an indicator of the way in which an anion will prefer to align in 
a local field, or does it too depend on coordinate choice?

Also, are there well-established experimental techniques for measuring 
dipole direction, as opposed to value?

Thanks,

Jeremy