PC GAMESS-related discussion club

Re: PC GAMESS ignores FVALUE?

Alex Granovsky
gran@classic.chem.msu.su

On Mon Jul 31 '06, Roman Zubatyuk wrote
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>It seems that the latest versions of the program ignores FVALUE keyword in $zmat. I'm trying to freeze internal coordinate to 6.0 using IFZMAT and FVALUE according to common GAMESS (US)/PC GAMESS documentation. In the input geometry this internal coordinate has value of 6.07. The PC GAMESS actually freezes the coordinate, but does not change its value to specified by FVALUE keyword. Is there any new keywords that have replaced the FVALUE?

>Here is my $ZMAT group:
> INPUT CARD> $zmat dlc=.t. auto=.t.
> INPUT CARD> ifzmat(1)=1,18,29 fvalue(1)=6.0 nonvdw(1)=18,29 $end

>Roman.
>

The following is a very brief description of several new keywords of the $ZMAT group.

AUTOFV (default .true.) means to generate fvalue array automatically. Any user input of fvalue is thus ignored. This option is especially useful for relaxed PES scans in DLC.

DLCTOL (default 1.0d-5) is the threshold used at several stages during DLC generation, as well as to impose geometrical constrains. Normally you do not need to alter it, however, in some cases setting it to, say, 1d-7 can help generating required number of linearly independent DLC coordinates.

IFRZAT is the array of atom numbers you want to freeze during geometry optimization using DLC. More precisely, the distances between all chosen atoms will be frozen, however, they will be allowed to rotate and translate as the single, united group (rigid body).

Hope this helps
Alex Granovsky

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