Subject: Re: CCL:how to 'protect' point charges in Gaussian?

From: Victor Lua~na <[email-masked]>
Date: Tue, 29 Apr 2003 17:19:57 +0200 (METDST)

> From: David Price <[email-masked]>
>  I am trying to set up a calculation that has an oxide cluster
> surrounded by point charges, but want to restrict the ability of the
> oxide ions to polarise to much towards the positive point charges.
> The point charges are included to mimic other ions in a lattice and thus
> even the positive charges will repel the electron gas cloud of the oxide
> ions at some distance from the point charge corresponding to the
> positive
> ion's 'radius'.  How do I do this in Gaussian?  I thought of using
> pseudo-potentials centred on the positive point charges, but wasn't sure
> if I could get one the right shape.

Dave,

  Perhaps you can find the next reference useful for your purpose.

@article{ov-LR2001,
   author    = { V. Lua{\~n}a and J. M. Recio
                 and A. Mart{\'\i}n Pend{\'a}s and M. A. Blanco
                 and L. Pueyo and R. Pandey },
   title     = { Practical Embedding for Ionic Materials. {I}.
                 {C}rystal adapted pseudopotentials for the {MgO} crystal },
   journal   = { Phys. Rev. B },
   volume    = { 64 },
   year      = { 2001 },
   pages     = { 104102-1--11 },
   abstract  = {
      We present a new method of deriving Effective Core Potentials
      (ECP) for negative and positive ions. The new ECPs are adapted
      to ionic crystals and can be used as components of an embedding
      model in most Quantum Chemistry codes. Cluster-in-the-lattice
      calculations of several defects and impurity centers in MgO are
      examined as a test.
      },
   }

                  Regards,
                           V. Lua~na