[molpro-user] Induced atomic dipole moments don't seem to be right (?)

[Tatiana Korona]

It is difficult to say what you do wrong in your finite field calculation 
without seeing the input, but for HF you can obtain the polarizability 
analytically,

  ***,He polarizability calculation
  memory,20,m


  geometry={he}

  basis=d-aug-cc-pvqz

  hf
  polari

  show,polxx

  polan=polxx*toang**3 angstrom3

In this example the polarizability is equal to 0.1959 Ang3, quite close to
what you cite as reference.

Best wishes,

Tatiana

  On Fri, 20 Mar 2009, Phillip Price wrote:

> Thanks to Kirk Peterson for helping me with an earlier question.
>
> I'm a new Molpro user running 2006.1.
>
> I need to calculate polarizability for some simple atoms and
> molecules.  I'm starting with atoms, to make sure I understand what
> I'm doing before moving on to more complicated systems.  Hydrogen
> works fine: apply a field of 0.001 a.u., use hf to predict the dipole
> moment, and divide by field to get the polarizability.  The result is
> correct to about 0.5% for hydrogen.
>
> But I run into problems with helium: using HF-SCF or MRCI or RS3, I
> get about the right value for total energy, and the methods all pretty
> much agree on the polarizability...but it differs from the correct
> value (as quoted in CRC) by about a factor of 4.5.  (Specifically,
> using Molpro and a field of 0.001 a.u., the induced dipole moment is
> predicted to be 0.00079 Debye, which converts to a polarizability of
> 0.0458 cubic angstroms.  CRC quotes a value of 0.205 cubic angstroms).
>
> I am pretty low on the Molpro learning curve, so please accept my
> apologies if I am doing something silly.
>
> Thanks for any help you can offer.
>
> --Phil Price
>
>
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Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory
University of Warsaw
Pasteura 1, PL-02-093 Warsaw, POLAND


`The man who makes no mistakes does not usually make anything.'
                                        Edward John Phelps (1822-1900)