TURBOMOLE Users Forum
TURBOMOLE Modules => Jobex: Structure Optimization and Molecular Dynamics => Topic started by: greisen on January 10, 2011, 06:34:21 PM
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Hi all,
I am optimizing a cluster of ions where I have first optimized using the highest spin state. After convergence I took those coordinates and transfered them into a new coordinate file. I then used a lower spin state but now I get problems with the scf convergence of the my cluster. I have used default settings for the scf-options and I am using RI in order to speed up calculation. Any flags to set that might help convergence of the cluster?
Thanks in advance
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Hi,
Try changing the following keywords (see the manual for details):
$scfdamp start=4.000 step=0.100 min=0.500
$scforbitalshift closedshell=.4
$scfiterlimit 150
If this does not help, just increase the damping (and perhaps the shift, too):
$scfdamp start=8.500 step=0.200 min=0.500
$scforbitalshift closedshell=.5
$scfiterlimit 200
For closed-shell systems, use automatic $scforbitalshift instead of closedshell.
These keywords are usually the most straightforward way of reaching convergence. Fermi-smearing can also be very helpful, especially when used with the "nue" option (see manual for $fermi)
Regards,
Antti
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In some cases, it may help convergence for low-spin, if you use the preconverged high-spin orbitals.