[molpro-user] Convergence problems for an already GAUSSIAN optimized geometry

[sachin joshi]

Dear MOLPRO users,

I tried to run a DFT geometry optimization calculation for a poly-propylene
carbonate molecule (16 atoms), with the following commands (the geometry is
not mentioned to keep the message short):

*****
basis=6-31g
ks, b3lyp
optg, maxit=1000

*****

I am getting the following error messages after going through 100
optimization steps:
.........
"?NO CONVERGENCE IN GEOMETRY OPTIMIZATION AFTER100 STEPS. LAST STEPSIZE:
0.00180000 LAST ENERGY CHANGE:    57.96700907"
.........
Geometry written to block  1 of record 700
? Error
? No convergence
? The problem occurs in optgeo

ERROR EXIT
CURRENT STACK:      MAIN
...............

As the initial geometry I used had been already optimized using GAUSSIAN, I
do not understand what may be causing any convergence problems. Also, using
maxit=1000 option does not make the program run more  than 100 steps?

I would really appreciate any help as I am relatively new to MOLPRO.

Thank you
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