potfiles:format4
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potfiles:format4 [2018/09/25 17:52] – daniel | potfiles:format4 [2020/10/12 10:50] (current) – [Format specification] #G header line pbro | ||
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points are possible, but the sampling points have to be given in ascending order. | points are possible, but the sampling points have to be given in ascending order. | ||
- | Preceding the data columns is a header with one line per column, containing the number of sampling | + | == Header == |
- | points in the corresponding column. Seperated by blank lines then the data columns follow. Each of | + | |
- | the columns has the form | + | |
+ | All potential files need a header block at the beginning, which is described in detail here: [[potfiles: | ||
+ | |||
+ | == Sampling points block == | ||
+ | |||
+ | Preceding the data columns is a block with one line per potential, containing the number of sampling | ||
+ | points in the corresponding potential. | ||
+ | |||
+ | Here is an example for a pair potential for two atom types, which requires three potential functions: | ||
+ | < | ||
+ | ## last header line | ||
+ | #E | ||
+ | |||
+ | 15 | ||
+ | 15 | ||
+ | 15 | ||
+ | </ | ||
+ | |||
+ | == Function tables == | ||
+ | |||
+ | Seperated by blank lines then the data columns follow. Each of the tables has the form | ||
< | < | ||
r_0 | r_0 | ||
Line 27: | Line 45: | ||
Similarly as for format 3, for potential functions that are a function of distance (e.g. pair potentials, EAM transfer functions), a smooth cutoff at the final sampling value is assumed and the value is not varied. | Similarly as for format 3, for potential functions that are a function of distance (e.g. pair potentials, EAM transfer functions), a smooth cutoff at the final sampling value is assumed and the value is not varied. | ||
+ | |||
+ | If the ''# | ||
+ | gradient of the function at the lower and upper boundaries. A value of $10^{30}$ or greater triggers the | ||
+ | usage of natural splines (curvature 0 at boundaries). You should not make the gradient variable at | ||
+ | boundaries where natural splines are specified. This will lead to undesired results. | ||
----- | ----- | ||
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A sample format 4 potential file for a binary system (EAM potential) is available | A sample format 4 potential file for a binary system (EAM potential) is available | ||
{{: | {{: | ||
+ | |||
+ | And here is a very simple pair potential for a monoatomic system. All lines starting with ''##'' | ||
+ | < | ||
+ | ## This is the header | ||
+ | ## F -- this is the Format line | ||
+ | ## 4 -- this is the Format number | ||
+ | ## 1 -- this is the number of potentials in this file | ||
+ | #F 4 1 | ||
+ | ## E -- this is the End of the header | ||
+ | #E | ||
+ | |||
+ | ## Sampling points block | ||
+ | ## There needs to be one line with the number of sampling points for each potential (1 in this example) | ||
+ | 14 | ||
+ | |||
+ | ## Function tables | ||
+ | ## One function table for each potential (1 in this example) | ||
+ | ## The number of lines must be equal to the number provided in the respective line in the distance block (14 in this example) | ||
+ | ## Each line has two values, the distance and the potential value | ||
+ | ## The first and the last line define the range of the potential | ||
+ | 2.7785714285714285e+00 8.4255614529302880e-01 | ||
+ | 3.2571428571428571e+00 2.0271471509245159e-01 | ||
+ | 3.7357142857142858e+00 2.2155522312087100e-02 | ||
+ | 4.2142857142857144e+00 -6.8303638148139376e-02 | ||
+ | 4.6928571428571431e+00 -4.9043278969706922e-02 | ||
+ | 5.1714285714285717e+00 -1.0946697911942214e-02 | ||
+ | 5.6500000000000004e+00 -1.0298525723152156e-02 | ||
+ | 6.1285714285714290e+00 -6.5685589306463460e-03 | ||
+ | 6.6071428571428577e+00 -2.0283626156443295e-03 | ||
+ | 7.0857142857142854e+00 1.2197714420628298e-02 | ||
+ | 7.5642857142857141e+00 2.2148801387662245e-02 | ||
+ | 8.0428571428571427e+00 1.4461939319528331e-02 | ||
+ | 8.5214285714285722e+00 9.9020972820913523e-03 | ||
+ | 9.0000000000000000e+00 0.0000000000000000e+00 | ||
+ | </ | ||
potfiles/format4.1537890774.txt.gz · Last modified: 2018/09/25 17:52 by daniel