[molpro-user] Fwd: Strange FCI result

[Doran Bennett]

Hi All,

I am running an FCI geometry optimization of BH ground-state. When run, this
gives me the result of a minimum at 1.1 Angstrom. But, if I simply generate
the FCI PEC, it is clear that the minimum is not even close to 1.1 angstroms
it is in the vicinity of 1.25 angstroms. I can't figure out why this
discrepancy is occurring since the gradient of the FCI optimization appears
quiet reasonable.

The input is:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

memory,200,m;

gprint,orbital;

basis=vdz;

Geometry
angstrom;
x,y;
B
H,1,r1;
end
r1=1.3426 angstrom;

{hf
wf,6,1,0;
save,2200.2;}

{fci
}

optg;
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------



The input for the PEC is:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
basis=vdz;


Geometry
angstrom;
x,y;
B
H,1,r1;
end
R_bond=[0.9 0.92 0.94 0.96 0.98 1.0 1.02 1.04 1.06 1.08 1.1 1.12 1.14 1.16
1.18 1.2 1.22 1.24 1.26 1.28 1.3];

r1=1.3426;

do i=1,#R_bond
r1=R_bond(i);

{hf
wf,6,1,0;
save,2200.2;}
E_HF(i)=energy;

{rccsd(t)
}

E_CCSD(i)=energc;
E_CCSDT(i)=energy;


{fci}

E_fci(i)=energy;

R_(i)=r1;

Table,R_,E_HF,E_CCSD,E_CCSDT,E_FCI;
enddo
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Any insight would be most helpful.

Doran Bennett


-- 
Web Page: http://bennett.doran.googlepages.com
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