# How to get started with Classical Density Functional Theory? [closed]

I'm trying to learn molecular classical DFT to model the adsorption of gases, particularly cryogenic hydrogen, in carbonaceous microporous solids. I'm totally new to this, just starting my thesis.

Do you think classical DFT is applicable for low temperature hydrogen? I originally thought about cryogenic hydrogen so about 30-70 K. But now that seems difficult.

Basically what I'm trying to simulate is hydrogen adsorption in carbonaceous solids, ideally at cryogenic temperatures. Since I'm just starting my Chemical Engineering Thesis I'm trying to do a basic approach via DFT (because that's what I've mostly seen in papers) and then add corrections , like I said I don't know about all the different theories that can be used for this. For example, this is the paper that I'm currently trying to follow, but sadly they only simulate CO2 and CH4 in fairly normal conditions, hence my question.

Do you have any recommendations on how to approach this?

I'm adamant on using DFT because my guiding professor knows quite a bit about it and I hope he can guide my through this theory.

• What is classical DFT?
– Camps
Commented Oct 5, 2022 at 17:03
• Density Functional Theory used for determining molecular density, for example the density of liquids or gases, instead of the electronic density. Commented Oct 5, 2022 at 17:32
• Quantum effects are strong for hydrogen at low temperatures, so I don't think classical DFT would be sufficient. How low are you thinking? There might be a way to reintroduce quantum behaviour, for example via path-integrals. Commented Oct 5, 2022 at 23:01
• Hydrogen absorption on surface sounds mostly like vdW. “Classical DFT” does not contain vdW, though there are many different corrections to fix this. However it also begs the question, why do you need DFT at all? Cannot do the calculations MM or DFTB level? (DFTB also contains vdW models, giving similar geometries and much faster than DFT )
– Greg
Commented Oct 7, 2022 at 3:02
• @PhilHasnip Good point. It would be better to know what effects exactly OP hopes to simulate.
– Greg
Commented Oct 7, 2022 at 3:04