Radial Distribution Function
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| RADIAL DISTRIBUTION FUNCTION | (by Luca)
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You can find the definition of the Radial Distribution Function (RDF) in the following:
Name: x.RDF
Launching: x.RDF > output (in output some details of the calculation are reported)
Input file: geom.dat, param.dat
Output file: Global.dat, fort.X (X = 1, 2, ..., N; see below)
Used subprograms: none
- General Description
x.RDF takes a system described in geom.dat and creates other 26 replica of the system adding or subtracting the lattice vectors. The initial system is at the centre of this 3x3x3 supersystem. It then computes the distances between the atoms in the initial system and the atoms in all the 26 outer cells, and inside the initial cell as well. It then computes the RDF and write it in fort.X (X = 1, N).
- Description of the Input files
In geom.dat there are the coordinates and label of all the atoms of my system in XYZ. Moreover, all atoms have to be written "in the VASP way", i.e. first all the atoms of type A, then all the atoms of type B and so on. An example of geom.dat for a box of 96 water molecules is reported here: File:Ex geomRDF.tgz
In param.dat, many different parameters, specifying the cell size and what kind of RDF you want, are specified. Here I attach an example: File:Ex paramRDF.tgz and in that page you can find all the explanation you need.
- Description of the Output files
In Global.dat you will find the positions of the atoms of your initial system, and their projections in all the other 26 contiguous cells.
In fort.X (X = 1, 2... N) you will find your RDF for the category X; please, see the link File:Ex paramRDF.tgz for more details about categories. Hence, if you specified 4 categories, you will have 4 output files (fort.1, fort.2, fort.3 and fort.4), one for each category.
- INSTALLATION STEPS
1) First of all, download the program:
and the example for the param.dat file: File:Ex paramRDF.tgz.
Uncompress them and compile the program: f77 RDF.f -o x.RDF. Place it in a directory of your choice (for simplicity, named directory A).
2) Copy your geometry in the file geom.dat (as I said, it has to be an XYZ file with all the atoms ordered by type).
3) Change the parameters in the param.dat file as you wish.
4) Now you can run the program typing: x.RDF > output
5) The files fort.X are ready to be plotted with gnuplot.