Charged cluster optimization problem
Posted: Fri Aug 04, 2006 6:42 am
Hello everybody!
I am trying to optimize a charged cluster. When LDIPOL=F everything goes smoothly, but when I turn LDIPOL=T, all forces go out of wack. The total energy increases after each geometry optimization step, and the forces usually grow too. During the first few steps the SCF iterations converge, but that convergence also degrades after each geometry optimization step.
I tried to increase the PREC key, change the algorithm (IBRION) and decrease POTIM (down to 0.01), but nothing seems to help.
Why does the optimization lead to bigger forces, and what can be done to improve geometry convergence with LDIPOL=T? How bad is the result if a charged cluster is optimized without LDIPOL corrections?
Thank you-
Vladimir
I am trying to optimize a charged cluster. When LDIPOL=F everything goes smoothly, but when I turn LDIPOL=T, all forces go out of wack. The total energy increases after each geometry optimization step, and the forces usually grow too. During the first few steps the SCF iterations converge, but that convergence also degrades after each geometry optimization step.
I tried to increase the PREC key, change the algorithm (IBRION) and decrease POTIM (down to 0.01), but nothing seems to help.
Why does the optimization lead to bigger forces, and what can be done to improve geometry convergence with LDIPOL=T? How bad is the result if a charged cluster is optimized without LDIPOL corrections?
Thank you-
Vladimir