## Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly

** Re^2: Optimization of conical intersection with penalty function method: how to control the gap? **
GrEv

grevgen13@gmail.com

Dear Alex,Thanks very much for your reply.

Just a curios question, what does the SHIFT option do?

Best regards,

Evgeniy

On Sat Oct 22 '16 6:00pm, Alex Granovsky wrote

----------------------------------------------

>Dear Evgeniy,

>there is no direct control over the energy gap for penalty-based CoIn

>optimization procedures. The gap can be controlled indirectly using

>parameters defining a penalty function. The larger is the "strength"

>of penalty function the smaller will be the gap. With Firefly, the

>strength is controlled by the parameter B of $mcaver group.

>Kind regards,

>Alex

>

>

>

>

>

>

>On Sat Oct 22 '16 11:50am, GrEv wrote

>-------------------------------------

>>Hello,

>>I am doing optimization of the minimum energy conical intersection using the penalty function method, with the following input (from the manual, p. 176) :

>>$MCAVER TARGET=MIXED PENLTY=2 XGRAD=.F. $END

>>$STATPT OPTTOL=0.00005 NSTEP=500 method=qa trmax=0.05 dxmax=0.05

>> HSSEND=.f. $END

>>$NUMGRD ORDER=2 DELTA=0.01 ISTATE=1 JSTATE=2 NGRADS=2 PRAXES=1 $END

>>Using this input I found a conical intersection (CoIn), with the final gap between the states of 0.003. I'd like however to have a smaller gap, let's say 0.0001. How this could be done. I've tried to use the SHIFT option in $MCAVER, setting SHIFT=0.0001. It however didn't do the job. I got a CoIn with almost the same gap as before.

>>Many thanks!

>>Evgeniy

Sat Oct 22 '16 7:39pm

This message read **390** times