Theory and UG for the SurfaceKinetics BC
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@RemDelaporteMathurin, I think version this can be used as a starting point. There are two points that I'd like to discuss:
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I think we also need @ehodille 's review on this one |
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| Modelling hydrogen retention or outgassing might require considering the kinetics of surface processes. | ||
| A representative example is the hydrogen uptake from a gas phase, when the energy of incident atoms/molecules is not high enough to | ||
| overcome the surface barrier for implantation. The general approach to account for surface kinetics :cite:`Pick1985, Hodille2017, Guterl2019, Schmid2021` consists in |
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Vladimir, do you not want to also mention your papers ? I think you implemented and used this kind of model in you laser desorption papers (but it is up to you).
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@ehodille, well, I used, yes. However, I intended to mention here the pioneers, whereas my papers on LID were mainly based on your works.
docs/source/theory.rst
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| \dfrac{d c_\mathrm{s}}{d t} = J_\mathrm{bs} - J_\mathrm{sb} + J_\mathrm{vs}~\text{on}~\delta\Omega | ||
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| where :math:`J_\mathrm{bs}\,[\mathrm{m}^{-2}\,\mathrm{s}^{-1}]` is the flux of hydrogen atoms from the subsurface (bulk region just beneath the surface) onto the surface, | ||
| :math:`J_\mathrm{sb}\,[\mathrm{m}^{-2}\,\mathrm{s}^{-1}]` is the flux of hydrogen atoms from the surface into the subsurface, and :math:`J_\mathrm{vs}\,[\mathrm{m}^{-2}\,\mathrm{s}^{-1}]` is the net flux of hydrogen |
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does J_vs contains the desorbing flux and all abstraction fluxes (ELy Rideal recombination etc) ?
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In general, yes, but it should be defined by a user. Here is an example from one validation case on how it can be defined:
def J_vs(T, surf_conc, t):
phi_atom = SP * Gamma_atom * (1 - surf_conc / n_surf) # adsorption
phi_exc = Gamma_atom * sigma_exc * surf_conc # abstraction
phi_des = 2 * nu0 * (lambda_des * surf_conc) ** 2 * f.exp(-2 * E_des / F.k_B / T) # desorption
return phi_atom - phi_exc - phi_desThere was a problem hiding this comment.
Maybe this could be explicited then? something like
is the net flux of hydrogen atoms from the vacuum onto the surface (eg recombination, dissociation, Eley-Rideal recombination, etc.).
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In this case, should we somehow clarify that the flux comes onto the surface: J_vs = +Dissoc. - Recomb. - Eley-Rideal recomb ...?
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Maybe just say J_vs = J_in - J_out where J_in is the sum of all fluxes coming from the vacuum to the surface and J_out from the surface to the vacuum
Or something like that and then give a few examples
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A few examples on different processes that can be included?
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Yes just like you had in your previous comment
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I updated this part. Let me know what you think.
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Looks good to me!
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@KulaginVladimir I think we can merge this unless @ehodille has something else to add |
Proposed changes
Following #798, this PR adds documentation on the
SurfaceKineticsBC to Theory and UG sections of docs.To-do:
Types of changes
What types of changes does your code introduce to FESTIM?
Checklist