How to use Firefly?

Instructions for the impatient

• Copy Firefly excecutable and libraries to C:\FIREFLY\
• Create a text file named INPUT in the current directory that looks something like this (note all input keywords starting with "$" sign are preceeded by a single blank character at the beginning of each line!):

   $contrl scftyp=RHF runtyp=ENERGY mplevl=2 units=ANGS icharg=0 mult=1 $end
   $system timlim=30 memory=500000 $end
   $basis gbasis=N31 ngauss=6 ndfunc=1 nffunc=0 npfunc=1 diffsp=.TRUE. $end
   $guess guess=huckel $end
   $data 
  Water MP2/6-31+G(d,p) single point energy calculation 
  CNv 2 
  
  O  8.0  0.00000000       0.00000000       0.11761300
  H  1.0  0.00000000       0.75734800      -0.47045000  
   $end
  

• C:\FIREFLY\FIREFLY.EXE > water.out
• After the job finishes (in a fraction of a second on modern hardware), you can inspect the output file with a text editor.

More detailed instructions

• Getting started on Windows
• Getting started on Linux
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• Download Firefly sample input files
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• Download most recent Firefly documentation

  The complete documentation for Firefly is presently work in progress. Current documentation is spread over several files together covering almost all the functionality of the Firefly version 8.1.1. These files were created as the result of activity of a small group of volunteers within a framework of the dedicated Documentation Project. The contribution of all group members to the Firefly Project is highly appreciated. Our special thanks to Thomas Pijper and Pedro Silva for their excellent work! Last updated: December 7, 2015

• Some additional keyword descriptions not present in the old manual can be found on the Firefly discussion forum
• Various README files on the selected Firefly's features
• List of the PC GAMESS specific options up to the (ancient - May 1999!) PC GAMESS version 5.2. These older options are however still fully supported by the up-to-date Firefly.
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• A severe outdated documentation on how to use Firefly and the PC GAMESS most efficiently

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