[molpro-user] Multipole Moments via GEXPEC and CCSD(T)

[Christian Cioce]

Hi, I'm having trouble computing multipole moments at the CCSD(T) level of
theory with the GEXPEC keyword. Using a similar sample input for H2O
(within the Molpro User's Manual), I have the following*properly working* input
file:

geometry={
2
N2 Monomer
N          0.000000      0.000000     -0.549000
N          0.000000      0.000000      0.549000
}
geomtyp=xyz

gexpec,dm,sm,qm                       !compute dipole and quadrupole moments

$methods=[hf,multi,ci]                !do hf, casscf, mrci
basis=AV5Z
do i=1,#methods                       !loop over methods
$methods(i)                           !run energy calculation
e(i)=energy
dip(i)=dmz                            !save dipole moment in variable dip
quadxx(i)=qmxx                        !save quadrupole momemts
quadyy(i)=qmyy
quadzz(i)=qmzz
smxx(i)=xx                            !save second momemts
smyy(i)=yy
smzz(i)=zz
enddo
table,methods,dip,smxx,smyy,smzz        !print table of first and second
moments
table,methods,e,quadxx,quadyy,quadzz    !print table of quadrupole moments

This input file renders appropriate (normal) output:

 METHODS   DIP      SMXX          SMYY          SMZZ
 HF        0.0   -7.71965855   -7.71965855   -8.64863534
 MULTI     0.0   -7.52595656   -7.52595656   -8.71606123
 CI        0.0   -7.59202157   -7.59202186   -8.72499509

 METHODS        E           QUADXX       QUADYY        QUADZZ
 HF        -108.9928938   0.46448839   0.46448839   -0.92897679
 MULTI     -109.1415178   0.59505234   0.59505234   -1.19010467
 CI        -109.3997302   0.56648690   0.56648647   -1.13297337


But when I then alter the methods in the original input file to calculate
the moments following a CC calculation, the results aren't as expected...

Truncated input file:

$methods=[hf,mp2,ccsd,ccsd(t)]

and the resulting output:

 METHODS   DIP      SMXX          SMYY          SMZZ
 HF        0.0   -7.71965855   -7.71965855   -8.64863534
 MP2       0.0   -7.71965855   -7.71965855   -8.64863534
 CCSD      0.0   -7.71965855   -7.71965855   -8.64863534
 CCSD(T)   0.0   -7.71965855   -7.71965855   -8.64863534


 METHODS        E           QUADXX       QUADYY        QUADZZ
 HF        -108.9928938   0.46448839   0.46448839   -0.92897679
 MP2       -109.4037581   0.46448839   0.46448839   -0.92897679
 CCSD      -109.3945766   0.46448839   0.46448839   -0.92897679
 CCSD(T)   -109.4155011   0.46448839   0.46448839   -0.92897679


It seems as though the CC routines aren't generating a new wavefunction or
dumps for the properties routine to use and so when requested, the
multipoles are using the original SCF wavefunction to calculate the
multipoles, but I'm not sure of that. Am I doing something wrong in my
input file? All I want to do is calculate the quadrupole tensor for the N2
monomer at the CCSD(T) level of theory.

Thanks in advance for your help!

Best,
Chris
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