Introduction to General Atomic and Molecular Electronic Structure System (GAMESS)

Today the theoretical exploration of molecular properties is easily accessible to researcher in different scientific disciplines. This is due to the rapid development in computer hardware and software that has provided the inexpensive tool to perform the quantum mechanical calculations on molecules of different sizes.
General Atomic and Molecular Electronic Structure System (GAMESS) is one of the software capable of doing semiempirical, ab initio (relativistic and nonrelativistic), Density Functional Theory (DFT) and molecular dynamics calculations in both sequential and parallel modes.
The software is available free of charge for academic researchers. The software has been compiled to run under different operating systems (Windows, Linux, Unix, Mac OS X) on different types of machines i.e. from laptops to high performance computer clusters.

How to Get GAMESS
Two main versions of GAMESS, i.e., PC-GAMESS and GAMESS-US are available from following websites.

Firefly (PC GAMESS) http://classic.chem.msu.su/gran/gamess/index.html
(GAMESS-US) http://www.msg.ameslab.gov/gamess/

GAMESS Input file
The input file format in both GAMESS versions are the same, following is the sample input file for single point energy calculations on water molecule at RHF/STO-6G level of calculations.

$CONTRL SCFTYP=RHF RUNTYP=ENERGY ICHARG=0 MULT=1 $END
$SYSTEM TIMLIM=700 MWORDS=6 $END
$BASIS GBASIS=STO NGAUSS=6 $END
$DATA
H2O RHF/STO-6G single point energy calculations
C1
O 8.0 -1.182293022 0.000000000 -1.702810546
H 1.0 -1.182293022 0.759337000 -1.106767546
H 1.0 -1.182293022 -0.759337000 -1.106767546
$END

The input file should always consist of 4 main parts or decks (in black color), i.e. $CONTRL, $SYSTEM, $BASIS and $DATA, each deck includes special keywords (in blue color) and each keyword has different options (in green color). The last deck in the sample input file is the $DATA. The sequence of lines (from top to bottom) in this deck is: Title section, point group symmetry of molecule and Cartesian coordinates (x,y,z) of atoms in water molecule. The atomic number (Z) immediately appears after the chemical symbol of the element (in pink color).

Graphical Interfaces
Among the graphical interface programs available for making the input files and viewing the contents of GAMESS output files; ChemCraft and Ghemical are introduced here. They are available from following websites.

ChemCraft: http://www.chemcraftprog.com/
Ghemical: http://www.uku.fi/~thassine/projects/ghemical/

GAMESS Community
By registering through the GAMESS websites, users can join to the GAMESS community and post their questions and problems to other users and get the feedback from them. All users automatically can read the discussions between other users. This will help them to become familiar with lots of technical hints in quantum chemical calculations.

GAMESS-UK
This version of GAMESS is originally different from the PC-GAMESS and GAMESS-US, it is free for researchers in UK. For more details please check this link:
http://www.cfs.dl.ac.uk/

Other Useful Websites
The following website of Ernst Schumacher is one the inetersting websites for GAMESS users. http://www.chemsoft.ch/index.htm

References
Firefly and GAMESS-US manuals downloadable from following websites
http://classic.chem.msu.su/gran/gamess/index.html
http://www.msg.ameslab.gov/gamess/