Summary : ab initio NMR calculation (paramegnetic system)



 I thank you all the persons that answer me and try to help me
 I summary the answers (4) , maybe it could be halpfull some someone else.
 Best Regards
                       Alessandra
 Questions:
 >
 > Dear All,
 >
 >         I wonder if someone have performed ab initio NMR
 > shielding tensor calculations on paramagnetic compounds by means of GIAO
 > or CSGT methods.
 >        Could you point me some paper concerning the argument? or could you
 > write me your knowledge about the reliability of GIAO and CSGT NMR
 > shielding tensor calculations on paramagnetic molecules?
 >        I will summary all the answers.
 >        Thank you
 >
 >  Alessandra
 Answers:
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 From: "Y. Tantirungrotechai"
 You might like to ask Dr. K. Ruud who implement GIAO in Dalton.
 I asked to Dr. K. Ruud, follow his answer
 From:Kenneth Ruud
  As far as I know from reading about the NMR of
 paramagnetic molecules, there are no problem in calculating the
 NMR parameters of such compounds. There might be important higher-order
 contributions from e.g.spin-orbit coupling. However, these may aso be
 calculated with e.g. Dalton.
 The main problem is normally that programs cannot easily or accurate treat
 open-shell systems. Dalton should be able to do a fair job on these
 systems.
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 From: Georg Schreckenbach
 I have read statements like "truly
 quantitative calculations of chemical shifts for paramagnetic compounds
 have not yet been reported" (B=FChl et al., J. Comp. Chem. 1999, 20, 91)
 whi=
 ch supports this view.
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 From: Douglas J. Fox
   Cheeseman, et. al. looked at this when implementing the procedures for
 Gaussian94.  J. Chem. Phys. vol 104, pp 5497 (1996).
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 From:Noah W. Allen, III
 You might want to check a review article by A.C. de Dios found in the
 "Journal of Progess in NMR Spectroscopy", 82 (1985) 5035.  It's an
 excellent
 source of review for this material.
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   Alessandra Villa                            ale { *at * } sg2.csrsrc.mi.cnr.it
   PhD-Student
   Dipartimento di Chimica Fisica ed Elettrochimica
   Universtita' degli Studi di Milano
   via Golgi 19
   20133 Milano-Italy
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