[molpro-user] CASSCF fails to converge

[Terry Frankcombe]

Can someone point me to how to get a FV CASSCF calculation on C + CH2 to
converge tightly?  If I only want the energy at a particular geometry, the
CASSCF converges in something like 6 iterations.  If I want to optimise
anything, though, the incipient optg is detected and the convergence
thresholds tightened (despite any global or local options).  Depending on
the geometry, the gradients and/or the steplength level off at a value
above the thresholds and stay there.  Increasing the number of iterations
doesn't help.

How can I either a) get the CASSCF to converge, or b) loosen the
convergence criteria (I really only want a loose optimisation)?

(2008.1-16)

Input below, output attached.


basis=AVDZ
geometry={Angstrom
	NoSym
        C1
        H1 C1 rCH1
        H2 C1 rCH2 H1 a1
        C2 C1 R H1 a2 H2 a3}

rCH1=1.07
rCH2=1.10
a1=132
a2=140
a3=150
R=9

{HF; WF 14 1 0}
CASSCF
optg
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