Author Topic: mpshift+ECP  (Read 5890 times)

resofidentity

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mpshift+ECP
« on: December 23, 2011, 09:10:19 am »
Dear Readers,
a principal question: The manual says, that mpshift does not work with ECPs. Which I perfectly understand for the Atom with the ECP. However, mpshift runs also for molecules containing atoms with ECPs without complaints. Now I wonder, how strong the shieldings of the other "non-ECP" atoms will be affected. I can imagine that nuclei far away from the ECP will not be affected at all. But now what about nuclei close to the ECP-atom. Lets say the hydrogen in AuH. Do you have any experiences/recommendations?
best regards and merry xmas!
  R

resofidentity

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Re: mpshift+ECP
« Reply #1 on: January 18, 2012, 07:51:42 am »
Hi,
meanwhile I fund out a bit more. It seems that the for the scalar relativistic calculations ECP and ZORA/DKH agree reasonable. However, there are the so called "heavy-atom shifts" which are basically SOC (and SSC ?) effects, and those influence
substantially on the absolute and relative shifts/shielding tensors:
http://pubs.acs.org/doi/suppl/10.1021/jp202327z

Any comments on that?
best regards
  R

Dr_Nick

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Re: mpshift+ECP
« Reply #2 on: January 28, 2014, 11:18:30 am »
I am facing the same question in my calculations.
In a molecule containing A and B linked by a bond or closeby, are the NMR parameters of atom A affected by an ECP on atom B? (compared to the case when B is described by an all electron basis set)

I would naively assume that the effect is small, since the ECP describes the core states of B and these would have only very small effect on the electronic environment of A.