[molpro-user] Induced atomic dipole moments don't seem to be right (?)
pnprice at lbl.gov
Fri Mar 20 17:02:49 GMT 2009
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.
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