[molpro-user] Quadrupole moment

Tatiana Korona tania at tiger.chem.uw.edu.pl
Thu Sep 29 17:34:36 BST 2011

similar issues have been discussed several time on molpro-user list, e.g.

On Thu, 29 Sep 2011, lilianna bryjko wrote:

> Hi,

I would like to ask how Molpro calculate quadrupole moment at the origin. I need get the value of charge for certain r (distance between charges) for each transition. I know how to do it using dipole moment, but I am confused a little with quadrupole moment. For example in a case of RHF calculations I get output: 
Dipole moment /Debye                   3.66434903    -3.50862417     0.00000000

 !RHF expec            <1.1|XX|1.1>   -35.258672915978
 !RHF expec            <1.1|YY|1.1>   -40.017295422307
 !RHF expec            <1.1|ZZ|1.1>   -34.966530874802
 !RHF expec            <1.1|XY|1.1>    -6.812741388569

 !RHF expec          <1.1|QMXX|1.1>     2.233240232577
 !RHF expec          <1.1|QMYY|1.1>    -4.904693526919
 !RHF expec          <1.1|QMZZ|1.1>     2.671453294341
 !RHF expec          <1.1|QMXY|1.1>   -10.219112082854
 !RHF expec          <1.1|QMRR|1.1>  -110.242499213091

What is the difference between <1.1|XX|1.1> and <1.1|QMXX|1.1>.

Best wishes,


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)

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