How to combine ZBL and eam/alloy potentials for different atom types?

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1

This is the first time I want to use multiple interatomic potentials. I want to simulate oxygen irradiation into iron. I have a file for the Fe-Fe interactions (this is how I used it):

pair_style eam/alloy
pair_coeff * * fe_mendelev_eam_alloy.potential Fe

In my current problem, O-O will never happen and I believe that O-Fe can be simply simulated with a ZBL potential. The O ion is very energetic and the Fe sample is really thin. How can I combine these two interactions? I tried:

pair_style hybrid eam/alloy zbl
pair_coeff 1 1 eam/alloy fe_mendelev_eam_alloy.potential Fe
pair_coeff 1 2 zbl 2.0

And I get:

ERROR: Illegal pair_style command (src/pair_zbl.cpp:184)
Last command: pair_style hybrid eam/alloy zbl
2

Hi @acgc99 ,

Please refer to the zbl pair style documentation. It requires inner switching distance and outer cutoff radii when it is declared. This is where this error stems from.

3

Thanks for your response. This is the modified code:

pair_style hybrid eam/alloy zbl 3.0 4.0
pair_coeff * * eam/alloy C:\Users\acgc99\Local\Sync1\Estudios\UA\PhD\Codes\InteratomicPotentials\Fe\fe_mendelev_eam_alloy.potential Fe NULL
pair_coeff 1 2 zbl 2.0 3.0

I’m just putting random values for the arguments. Which arguments are being applied? I mean 3.0 4.0 or 2.0 3.0? Isn’t this redundant?

This code also produces an error: ERROR: All pair coeffs are not set (src/pair.cpp:253). If I add pair_coeff 2 2 zbl 2.0 3.0, then I get ERROR: Incorrect args for pair coefficients (src/pair_zbl.cpp:221) for that line. For my particular problem, there’s only going to be a single O atom per simulation.

4

This depends on your model. The argument provided in the pair_style and pair_coeff commands are not the same. Please, read the manual.

Please consider (re-?)reading the guidelines of the forum. They provide steps to debug these issues on your side before submitting a simplified version of your problem to get more insightful comments.

The following minimal working example runs on my computer without producing an error:

units metal
boundary p p p

lattice sc 1.
region mybox block 0 1 0 1 0 1

create_box 2 mybox

pair_style hybrid eam/alloy zbl 3. 4.
pair_coeff * * eam/alloy AlO.eam.alloy Al NULL
pair_coeff 1 2 zbl 12. -8. #  Dummy values
pair_coeff 2 2 zbl -8. -8. # Dummy values

This was done using the version of 19 nov 2024 (I didn’t recompile a more recent version on this machine). From my perspective, the error stems from some writing of the commands and thus requires a more deep understanding of the manuals’ instruction on how to format your input file.

If you think there is still an issue from the parsing of the pair styles and a bug in the code, please provide more details on your version of the code and all the input files you are using.

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