PC GAMESS/Firefly-related discussion club

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Pedro Silva
pedros@ufp.pt

All three programs use the same command line intructions. They require output and punch
files from two calculations of the same system, with the same coordinates, but different
spin multiplicities. These files MUST be named as:

First.out and First.dat        (for the first spin multiplicity, i.e. that with the HIGHER energy )
Second.out and Second.dat     (for the second spin multiplicity)


All programs produce several files:

results.txt     (geometries, graidents, energies, etc...)
results.xyz     (geometries in xyz format)
new_geom.txt     (the next geometry in the MECP optimization)
new_grad.txt    (computed gradient - output only when BFGS update is selected)
hessian.txt     (computed hessian - output only when BFGS update is selected)
vec1.txt     (orbitals for the first state, taken from First.dat)
vec2.txt     (orbitals for the second state, taken from Second.dat)


new_geom.txt, vec1.txt and vec2.txt must be combined in order to build input files
(First.txt and Second,txt) for a new round of computation. The easiest way to do this
is to have all other input commands in separate files (e.g. First_temp.txt and Second_temp.txt),
and concatenate them as needed.




They differ on the type of PcGamess/Gamess(US) files they act on:


mecp_from_stapt_nstep1         acts on PcGamess RUNTYP=OPTIMIZE jobs produced with  $statpt nstep=1 $end
mecp                        acts on PcGamess RUNTYP=GRADIENT jobs
mecp_sol                   acts on Gamess(US) RUNTYP=GRADIENT jobs with $PCM group*



*In the first paper I published using MECP (Silva & Ramos (2007), J. Phys. Chem. B,111, 12883-12887), I found that in my system  the MECP
geometry in gas phase was quite different from the one in solution. Therefore, if you want to find MECP for solvated species you might have to use mecp_sol AND Gamess(US), which has a much slower DFT implementation the PcGamess/Firefly.


               

DISCLAIMER: The programs were built for my personal use. My programming skills are limited (to say the least) and I am sure that a good

programmer would be able to make them much more user-friendly.

This message contains the 105 kb attachment [ MECP_programs.zip ] Programs for MECP computation according to Harvey et al. (1998)