Subject: CCL:spin-spin coupling constants

From: Tanja van Mourik <t.vanmourik(at)ucl.ac.uk>
Date: Mon, 29 Mar 2004 18:30:47 +0100 (BST)

Hi CCL'ers,

With risk of showing my ignorance on this subject:
I am calculating NMR spin-spin coupling constants with Gaussian 03.
I found that specifying either the 12C or 13C isotope gives identical
couplings. I am rather puzzled by this. As 12C contains an even number 
of protons and neutrons, it is NMR inactive. Can one calculate couplings
for inactive atoms? Why are the 12C and 13C couplings identical? Does
Gaussian perhaps automatically choose the NMR-active isotope?

Any help on this would be greatly appreciated.

Tanja
-- 
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   Tanja van Mourik                                                
   Royal Society University Research Fellow
   Chemistry Department 
   University College London  phone:  +44 (0)20-7679-4663      
   20 Gordon Street          e-mail: work: T.vanMourik(at)ucl.ac.uk 
   London WC1H 0AJ, UK               home: tanja(at)van-mourik.me.uk

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