Choose Multipole Expansion Center

Is the origin the only option or is there a way to set the expansion center for the MULTIPOLE(N) expansion to the center-of-mass, center-of-nuclear-charge or a specific set of coordinates?

If not, this would be a nice feature.

PROPERTIES_ORIGIN [0.0, 0.0, 0.0] allows you to set the origin at an arbitrary point.

Thank you. And now I see its there in the manual, sorry. But I don’t get it to work.

memory 600 mb

molecule h2o {
H   -0.757142708906564    0.000000000000000   -0.523174282516128
H    0.757142708906564    0.000000000000000   -0.523174282516128
O    0.000000000000000    0.000000000000000    0.065396785314516
#symmetry c1

set {
basis aug-cc-pVTZ


I get the same values of the moments regardless of the value of ‘properties_origin’, [1,1,2], ‘COM’ or ‘NUCLEAR_CHARGE’. Am I missing something here?

Apologies, I should have been more clear. The keyword is used as follows:

set PROPERTIES_ORIGIN [10.0, 10.0, 10.0]

Please note the property keyword was renamed to properties in the next Psi4 version to avoid Python keyword collisions.

Aha, thank you!

Yes I’ve seen that about ‘properties()’. But on my version (1.1 through conda) it isn’t recognized. However, when you change I guess the alias ‘prop()’ will stay the same.

Yes ‘prop’ will stay. Glad this fixed your issue.