Alex Granovsky
gran@classic.chem.msu.su
well, there are lots of people (including myself) who believes
that INTRINSIC REACTION COORDINATE does not have much sense at
all - e.g., unlike stationary points on PES, it is non-invariant
with respect to arbitrary diffeomorphic transformation of
coordinate system. More precisely, if you calculate IRC, then
transform coordinates, calculate IRC in new coordinates, and then
back-transform coordinates, the two IRCs will be different.
Regards,
Alex
On Mon Jun 21 '10 6:37pm, Jim Kress wrote
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>Doesn't "freezing" a coordinate in an INTRINSIC REACTION COORDINATE calculation defeat the whole purpose of performing the INTRINSIC REACTION COORDINATE calculation? After all, you are looking for a reaction path which, if you "freeze" one coordinate, will not be a reaction path, it will be just an artificial construct that has no real physical meaning.
>Look here:
>http://blake.lsmc.u-bordeaux.fr/Ampac/algorithms.html#pathalgohttp://blake.lsmc.u-bordeaux.fr/Ampac/algorithms.html#pathalgo
>for some deeper insight.
>On Sun Jun 20 '10 9:29pm, Eldar Mamin wrote
>-------------------------------------------
>>Dear Fireflly Users,
>>Can I freez bond length in IRC job?
>>To define molecule I use Z-matrix, and function ifreez to make coordinate frozen. Following that way I get Saddle point, but during runtyp=irc no coordinate is kept frozen.
>>Can anyone help me?