Ar-Cu interaction parameters

Hello all,

I want to simulate the condensation process of vapor argon on a copper solid surface. The temperature of argon is at 87.3 K and copper surface at 85 K. I have used LJ (6-12) potential for the interaction between all pairs of atoms. I also used Lorentz-Berthelot rule for determining the LJ parameters between argon and copper. Are these assumptions realistic enough to predict the interactions between copper and argon pairs?
For more information, I have provided my LAMMPS code below.

Thanks,

Saeed

Hello all,

I want to simulate the condensation process of vapor argon on a copper solid surface. The temperature of argon is at 87.3 K and copper surface at 85 K. I have used LJ (6-12) potential for the interaction between all pairs of atoms. I also used Lorentz-Berthelot rule for determining the LJ parameters between argon and copper. Are these assumptions realistic enough to predict the interactions between copper and argon pairs?

please do what every smart researcher does in this case: look up relevant publications of simulations of the same or similar systems and some experimental papers and try to compare your procedure, parameters, and results with what those publications describe. if you plan to publish your simulation results, you need to do that anyway, so why not do it right away?

axel.

Thanks Axel.

I have explored many MD publications that used LB rule for Cu-Ar interactions but the reviewer of my paper says it cannot predict the real characteristics between this pair of atoms. Also, I have seen publications claiming that we should use EAM potential for more accurate Cu-Cu interactions while there are others using LJ potential. Now, I am confused which way is correct.

Saeed

Thanks Axel.

I have explored many MD publications that used LB rule for Cu-Ar interactions but the reviewer of my paper says it cannot predict the real characteristics between this pair of atoms.

so does the reviewer provide a reference for a viable alternative? or arguments why this cannot be?

Also, I have seen publications claiming that we should use EAM potential for more accurate Cu-Cu interactions while there are others using LJ potential. Now, I am confused which way is correct.

simulations use models and thus models are always approximations (which is why your mentioning of a temperature with a 0.1K precision for a simulation is rather worrying since you are not likely to have simulated a system large enough to warrant that precision from statistical analysis). whether an approximation is applicable, can only be validated by computing properties from your simulations, that can be compared to experimental measurements of the same or related processes. there is not the “one true way™” to do simulations and not the “one right and always correct™” choice of potentials. depending on what you are looking at, a classical model may not be applicable at all, or an all-LJ model may be sufficient. as mentioned before, this kind of validation is part of the standard simulation process and should have been done before you start your production simulation. simply stating, that others have used the same parameters and not validating them yourself is not sufficient. you have to consider the context. that includes the year and kind of research and state of the art at the time of the publication you are looking at and the specifics of the properties you are investigating. so what was acceptable 20-30 years ago may not be state of the art anymore. or settings and parameters for a simulation looking at completely different properties may not be transferable.

regardless of what i or somebody else will state here. it won’t help you with your review. you cannot argue with “some random dude on the LAMMPS mailing list said my parameters were ok”. you will have to provide hard evidence that your model is applicable or you can forget it.

axel.