Molcas Forum

wingsofephemera

Member

Registered: 2019-10-11

Posts: 10

Spin density matrix zeroes for triplet oxygen

Hi all, I calculated the triplet oxygen using D2h symmetry, the spin density matrix calculated is zero. Below are the input and output:

&SEWARD
GRID INPUT
grid=ultrafine
END OF GRID INPUT
Basis set
O.cc-pvtz....
O   0.000   0.000   $R1 ANGSTROM
End of basis
*NOCD
SYMMETRY
x y z
End of input

*>> COPY $MOLCAS_Project.GssOrb INPORB
*&SCF
>> COPY $Home/$MOLCAS_Project.saveorb INPORB

&RASSCF
SPIN
3
SYMMETRY
4
NACTEL
8 0 0
FROZEN
0 0 0 0 0 0 0 0
INACTIVE
2 0 0 0 2 0 0 0
RAS2
1 1 1 0 1 1 1 0
ITERATIONS
200 100
CIROOT
1 1 1

And a section of the output

      Mulliken spin population analysis for root number:  1
      ---------------------------------------------------


++    Molecular charges:
      ------------------

      Mulliken spin population per centre and basis function type
      ---------------------------------------------------

                O     
      1s       0.0000
      2s       0.0000
      2px      0.0000
      2pz      0.0000
      2py      0.0000
      *s       0.0000
      *px      0.0000
      *pz      0.0000
      *py      0.0000
      *d2+     0.0000
      *d1+     0.0000
      *d0      0.0000
      *d1-     0.0000
      *d2-     0.0000
      *f3+     0.0000
      *f2+     0.0000
      *f1+     0.0000
      *f0      0.0000
      *f1-     0.0000
      *f2-     0.0000
      *f3-     0.0000
      Total    0.0000

      Total electronic spin=    0.000000
--

The spin density matrix printed is also zero. Could someone tell me what have I missed here? Did I use the symmetry wrong? Or is it something dumb I've messed up...

Thanks in advance.

wingsofephemera

Member

Registered: 2019-10-11

Posts: 10

Re: Spin density matrix zeroes for triplet oxygen

Seems to be a problem with DMRG interface, from my locally modified version of OpenMolcas the DMRG was automated.
I guess the MPS spin density was not implemented? Would be odd though, since the RASSI module presumably uses spin density then where to find that for MPS?

Ok, thanks for reading though.