STRFACT is a program that computes total scattering factors from trajectory data computed using DLPOLY, CHARMM, LAMMPS and GROMACS.
The total static structure factor, S(q), is calculated from:
were Sij(q) is the partial static structure factor between atoms types i and j (e.g. carbon’s, hydrogen’s and nitrogen’s), calculated from the corresponding Fourier transform of the partial radial distribution function gij(r); r is the distance; q is the scattering vector; ρo is the average atom number density; R is the cutoff used in the calculation of gij(r); xi and xj are the atomic fraction of i and j; and bi(q) and bj(q) are the atomic form factors of the corresponding atom type, interpolated from recommended values in the International Tables for Crystallography. The term sin(π*r/R)/(π*r/R) is a Lorch type window function and is added to reduce the effect of using a finite cutoff in the radial distribution function calculation.
Besides the main program, three additional routines are also available: i) the "RDF" program, that computes radial distribution functions between (RDF) atom positions and centres of mass; ii) the "RDFTOTAL", that computes RDF between atom types (C, H, O, N, ...) or atom names; and iii) the program 'RDF2STRC', that computes the structural factor from RDF data. Aditional information regarding the programs installation procedure and their use can be found in the user manual that can be downloaded from HERE.
In order to keep the motivation in developing the software, I kindly ask that you register your download and please cite the reference below in your publications if the software was useful for your research:
- C.E.S. Bernardes; Zenodo 2024, http://doi.org/10.5281/zenodo.10473250
- C.E.S. Bernardes, K. Shimizu, J.N. Canongia Lopes; Mol. Simulat. 2018 , 44 478-484.
Other examples where this program was used include:
- K. Shimizu, C. E. S. Bernardes J. N. Canongia Lopes; Pure Appl. Chem. 2014, 86, 119–133.
- C.E.S. Bernardes, K. Shimizu, J.N. Canongia Lopes; J. Phys. Condens. Matter 2015, 27, 194116.
Strfact is free software, distributed under the terms of the GNU General Public License as published by the Free Software Foundation. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. For more information regarding the program features and instalation, follow the links on the left.