UT theoretical chemistry code forum

Dear，

I am a junior researcher major in geology, and I want to do some research on the diffusion of gas admolecules on the mineral surface. When I am trying to performance some simulations with eOn by following the AKMC tutorial, I found there is no parameter to set the pressure of the system.

Since my background is geology, I do not know if the pressure is important in the surface processes. Is the pressure must be calculated form the simulation as in a NVT MD simulation? But I don't figure out how to calculate the pressure with the eOn outputted result.

By the way, is there anyone who knows well the diffusion of admolecules would suggest me some references on how to calculate the diffusion coefficient by using the eOn results?

I am looking forward any reply. Thanks very much.

Mitch

We do not have code for constant pressure simulation in EON yet. Fortunately, given that you have a free surface, you would not expect pressure to play a significant role in the structure of the material.

I would suggest starting my running MD of your adsorbed molecule. If the molecule does not diffuse at the temperature that you are interested in, you could use the AKMC approach to identify the diffusion mechanisms and model the dynamics on the time scale of the diffusion.

graeme wrote:We do not have code for constant pressure simulation in EON yet. Fortunately, given that you have a free surface, you would not expect pressure to play a significant role in the structure of the material.

I would suggest starting my running MD of your adsorbed molecule. If the molecule does not diffuse at the temperature that you are interested in, you could use the AKMC approach to identify the diffusion mechanisms and model the dynamics on the time scale of the diffusion.

Thanks very much for your reply, professor.

Because our collaborator use PFG-NMR found the diffusion of the gas with mineral surface can not be described by a unified diffusion coefficient. So I am thinking maybe the gas admolecules diffuse a different way. I am trying use your eOn code to calculate the diffusion coefficient of admolecules. With comparing to a MD simulation result, we may find out the diffusion mechanisms and give better description to the experimental observations.

In your code package, you have several examples to demonstrate how to work with your software. And also I found your group have published some work on metal atom diffusion on a crystal surface. So, do you have a tutorial for calculating diffusion coefficient. and would you mind send me one?maybe based on one of your published work? And also I did not find the instruction to the unit of outputted result of eOn. would you mind let me konw this?


Thank your again and looking forward your reply.

Best Regards.

Mitch