[molpro-user] CASPT2 dipole moment

Tijs Karman T.Karman at science.ru.nl
Thu Feb 19 14:36:52 GMT 2015

Dear all,

I have a question about the CASPT2 program:
How does this program compute properties such as dipole moments?
I can't find this in the papers describing the program:
H.-J. Werner, Mol. Phys. 89, 645-661 (1996)
P. Celani and H.-J. Werner, J. Chem. Phys. 112, 5546 (2000)

I imagine there are multiple ways this could be implemented.
For example, one could calculate expectation values using the wave 
function up to first order.
In doing so, one might drop the second order term:
<Psi_0 + Psi_1 | \mu | \Psi_0 + \Psi_1>  = <Psi_0|\mu|Psi_0> + 
<Psi_0|\mu|Psi_1> + <Psi_1|\mu|Psi_0> + O(2)
The CASPT2 program of MOLCAS calculates properties from approximate 
first order density matrices.

Can someone tell me how this is implemented in MOLPRO?


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