[molpro-user] A question about second moment in molpro

Cong Wang eclipse at chem.helsinki.fi
Sun Dec 6 14:20:53 GMT 2009

Dear everyone,


 Excuse me, I have a question of the definition of second moment in
molpro. From the manual

SM      1       XX, YY, ZZ, XY, XZ, YZ  second moments

Seems the diagonal element is a positive definite quantity, while the
example on water molecule is negative

 METHODS     DIP           SMXX          SMYY          SMZZ
 HF        0.82747571   -5.30079792   -3.01408114   -4.20611391

Does the SM mean \sum_I Z_I R_I^2 - \sum_i r_i^2  or  (\sum_I Z_I R_I
- \sum_i r_i)^2 that counts both nuclei and electron?

Thank you very much
Best regards
Cong Wang

Ph. D. Student
Department of Chemistry
Laboratory for Instruction in Swedish
University of Helsinki
A.I. Virtanens plats 1
P.O. Box 55
FI-00014 University of Helsinki

More information about the Molpro-user mailing list