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** Re: Optimization of conical intersection with penalty function method: how to control the gap? **
Alex Granovsky

gran@classic.chem.msu.su

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 6:00pm

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