PC GAMESS/Firefly is an ab initio

Ab initio quantum chemistry methods

Ab initio quantum chemistry methods are computational chemistry methods based on quantum chemistry. The term ab initiowas first used in quantum chemistry by Robert Parr and coworkers, including David Craig in a semiempirical study on the excited states of benzene.The background is described by Parr...

 computational chemistry

Computational chemistry

Computational chemistry is a branch of chemistry that uses principles of computer science to assist in solving chemical problems. It uses the results of theoretical chemistry, incorporated into efficient computer programs, to calculate the structures and properties of molecules and solids...

 program for Intel-compatible x86, x86-64

X86-64

x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

 processor

Microprocessor

A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

s based on GAMESS (US)

GAMESS (US)

GAMESS is a computational chemistry software program that stands for General Atomic and Molecular Electronic Structure System. The original code started on October 1, 1977 as a National Resources for Computations in Chemistry project. In 1981, the code base split into GAMESS and GAMESS variants,...

 sources. However, it has mostly been rewritten (about 60-70% of the code), especially in platform-specific parts (memory allocation, disk input-output

Output

Output is the term denoting either an exit or changes which exit a system and which activate/modify a process. It is an abstract concept, used in the modeling, system design and system exploitation.-In control theory:...

, network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

), mathematic functions (e.g., matrix operations), and quantum chemical

Quantum chemistry

Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems...

 methods (such as Hartree–Fock, Møller–Plesset perturbation theory, and density functional theory

Density functional theory

Density functional theory is a quantum mechanical modelling method used in physics and chemistry to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. With this theory, the properties of a many-electron system can be determined by...

). Therefore, it is significantly faster than the original GAMESS. The main maintainer of the program is Alex Granovsky. From October 2008, the project is dissociated from GAMESS (US) and the Firefly name was added. Up to October 17, 2009, both names will be used but thereafter the package will be known solely as Firefly.

The Firefly website now includes the following notice for users of pre-Firefly versions of PC GAMESS:

As of December 4, 2009, the support of any PC GAMESS versions earlier than the first PC GAMESS/Firefly version 7.1.C is being abandoned. Therefore, users of the outdated PC GAMESS binaries (version 7.1.B and all earlier releases) are required to discontinue their use of the PC GAMESS and upgrade to Firefly.

External links

• PC-GAMESS vs G98W MP4SDTQ Performance Comparison
• PC GAMESS SCF Benchmark
• Ascalaph Quantum graphic interface for PC GAMESS