Exploring Al(111) Surface Adsorption Energies with Dacapo/Python

[Hanlin]

Hi.

I'm trying to calculate the adsorption energies at all high symmetry sites on an Aluminium (111) surface (consisting of a few atomic layers). The adsorbates are hydrogen atoms. I make sure that one hydrogen atom per primitive surface cell is adsorbed (i.e. one monolayer of hydrogen atoms is adsorbed onto the surface). Now I'd like to understand how the number of atomic layers (which are all perpendicular to the (111) direction) affect the adsorption energy: will it increase/decrease with an increasing number of atomic layers? Is it possible to understand this by plotting the charge density variations on the surface? I am using Dacapo/python by the way. If you have the answer, could you help me?

Best Regards

Someone who could really use your wisdom.

 

[Modey3]

Hanlin,

Have you ever tried plotting surface-energy vs. number of layers. If so you will find that for between 3-6 (depending on the system) that surface energy oscillates with number of layers. This is due to there being a higher fraction of occupied "surface-states" compared to the "bulk-states" My guess is that since surface-energy oscillates so does the absorption energy.

Best Regards

modey3

 

[quicknote]

Hello,

It's great to hear that you are using Dacapo/Python to explore adsorption energies on an Aluminum (111) surface. This is a very interesting and important topic in surface science. To answer your question, the adsorption energy is affected by several factors, including the number of atomic layers and the orientation of the surface. In general, as you increase the number of atomic layers, the adsorption energy may decrease due to the increased distance between the adsorbate and the surface. However, this also depends on the specific adsorbate and surface interaction, so it's important to consider other factors as well.

Using charge density variations on the surface can provide valuable insights into the adsorption energy. You can plot the charge density of the surface with and without the adsorbate to see how it changes and how the adsorbate affects the electronic structure of the surface. This can help you understand the nature of the adsorbate-surface interaction and how it may change with an increasing number of atomic layers.

I would also suggest looking into other techniques, such as density functional theory (DFT), to further investigate the adsorption energies on the (111) surface. DFT calculations can provide more accurate and detailed results compared to empirical methods like Dacapo/Python.

I hope this helps and wish you the best of luck with your research. Feel free to reach out if you have any further questions.

Best regards,