# FreeON

Stable release 1.0.8 / November 8, 2013; 3 years ago Fortran, C Linux, FreeBSD, Unix and like operating systems Computational Chemistry GNU GPLv3 freeon.org

FreeON is an experimental, open source (GPL) suite of programs for linear scaling quantum chemistry, formerly known as MondoSCF. It is highly modular, and has been written from scratch for N-scaling SCF theory in Fortran95 and C. Platform independent IO is supported with HDF5. FreeON should compile with most modern Linux distributions. FreeON performs Hartree–Fock, pure density functional, and hybrid HF/DFT calculations (e.g. B3LYP) in a Cartesian-Gaussian LCAO basis. All algorithms are O(N) or O(N lg N) for non-metallic systems.[1][2][3][4][5][6][7] Periodic boundary conditions in 1, 2 and 3 dimensions have been implemented through the Lorentz field (${\displaystyle \Gamma }$-point), and an internal coordinate geometry optimizer allows full (atom+cell) relaxation using analytic derivatives. Effective core potentials for energies and forces have been implemented, but Effective Core Potential (ECP) lattice forces do not work yet. Advanced features include O(N) static and dynamic response, as well as time reversible Born Oppenheimer Molecular Dynamics (MD).

## Developers

Developer Affiliation
Matt Challacombe Los Alamos National Laboratory
Eric Schwegler Lawrence Livermore National Laboratory
C. J. Tymczak Texas Southern University
Anders M. Niklasson Los Alamos National Laboratory
Anders Odell KTH Stockholm
Nicolas Bock Los Alamos National Laboratory
Karoly Nemeth Argonne National Laboratory
Valery Weber University of Zurich
C. K. Gan Institute for High Performance Computing
Graeme Henkelman University of Texas at Austin