[molpro-user] weird SCF convergence/reproducibility problem

[Gershom (Jan M.L.) Martin]

Dear MOLPRO gurus:

Very recently I ran into a peculiar example of a transition state for which
MOLPRO disagrees with every other code on the ROHF reference energy. See the
simple input below. I tried every SCF convergence acceleration/coaxing trick
in the book and a few that aren't, to no avail.

The other structures on the same PES do not exhibit the problem. Does
anybody have a clue what I am overlooking?

(And yes, I know this is a highly multiref problem. Still, ROHF should give
the same answer as Gaussian and ACES?)memory,8,m

Many thanks in advance!
Jan Martin


    4
E(UHF)=-262.355671204 au|Dpl=(0.5152,-0.4848,0) D||E(ROHF)=-262.338447756
au|Dpl=(0.9471,-1.9519,0) Debye
O    -0.832632    1.113558    0.000000
C     0.000000    0.281073    0.000000
O    -0.367117   -1.293021    0.000000
O     1.199748   -0.031341    0.000000
}
basis=vdz
int
{uhf;wf,30,2,2;occ,13,3;closed,12,2}
! yields the correct energy
!UHF STATE 1.2 ENERGY               -262.355671266903
!UHF STATE 1.2 DIPOLE MOMENT           0.20268671    -0.19074510
0.00000000
{hf;wf,30,2,2;occ,13,3;closed,12,2}
! yields a different energy, and dipole vector looks very different too
!RHF STATE 1.2 ENERGY               -262.331395031327
!RHF STATE 1.2 DIPOLE MOMENT           0.10470623    -0.21621532
0.00000000
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