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about DFT not predicting it: could it be that they used a non-relativistic model?
about DFT not predicting it: could it be that they used a non-relativistic model?
Given the energy scales involved, it's more likely that the issue lies with the approximations DFT makes to quantum mechanics, rather than the approximations quantum mechanics makes to quantum field theory.
I wonder what the largest molecular “ball” that we could build would be? How cool to have one you could see or hold?
this boronic thing (negative ion, really) they _might have seen_ has 241 (valence) electrons.. You'd expect a nice 240 given the symmetry, not a prime number Or maybe a less baity reason is those hints of B_80^- have captured H+ "nuclei", turning into almolecular atoms! Not oxyboronic at all
What do you mean by "turning into almolecular atoms"?
Having only just learned what DFT is by reading this article, could someone familiar with the field opine on how significant it would be to discover a physical system that conflicts so much with its predictions?
DFT is an approximation. It's good for some molecules and it's bad for others. There are many methods under the DFT umbrella, so it's more complicated. Some method are good for some molecules, other methods are good for others. Some molecules are easy and can be approximated by many methods, some molecules are hard and no method is good for them. It's not my area, but I'm sure B80 is one of the tricky ones. In genera…
Having only just learned what DFT is by reading this article, could someone familiar with the field opine on how significant it would be to discover a physical system that conflicts so much with its predictions?
DFT is an approximation. It's good for some molecules and it's bad for others. There are many methods under the DFT umbrella, so it's more complicated. Some method are good for some molecules, other methods are good for others. Some molecules are easy and can be approximated by many methods, some molecules are hard and no method is good for them. It's not my area, but I'm sure B80 is one of the tricky ones. In genera…
Original paper, not a single equation:
https://web.archive.org/web/20240129185108/https://www.owlne...
The N^3 is further reduced by high symmetry. Because structure relaxations are usually convergent, the 2007 DFT and MD calculations can be run on a regular laptop today, maybe even without a GPU!
The discrepancy has been exaggerated by the experimentalist, TFA quotes the original theorist. This is not the first time, and probably not the last time, that c&en has oversold an experimental result.
this boronic thing (negative ion, really) they _might have seen_ has 241 (valence) electrons.. You'd expect a nice 240 given the symmetry, not a prime number Or maybe a less baity reason is those hints of B_80^- have captured H+ "nuclei", turning into almolecular atoms! Not oxyboronic at all
What do you mean by "turning into almolecular atoms"?
Earlier quoted context omitted.
Given the energy scales involved, it's more likely that the issue lies with the approximations DFT makes to quantum mechanics, rather than the approximations quantum mechanics makes to quantum field theory.
I agree. There are some important relativistic correction for heavy atoms like Gold where the inner electrons are "rotating" too fast near the nuclei, but for Boron it's not necessary to do that correction.
Having only just learned what DFT is by reading this article, could someone familiar with the field opine on how significant it would be to discover a physical system that conflicts so much with its predictions?
DFT is an approximation. It's good for some molecules and it's bad for others. There are many methods under the DFT umbrella, so it's more complicated. Some method are good for some molecules, other methods are good for others. Some molecules are easy and can be approximated by many methods, some molecules are hard and no method is good for them. It's not my area, but I'm sure B80 is one of the tricky ones. In genera…
Earlier quoted context omitted.
I agree. There are some important relativistic correction for heavy atoms like Gold where the inner electrons are "rotating" too fast near the nuclei, but for Boron it's not necessary to do that correction.
but, don't you need it already for C60?
It's very different in a heavy atom like Gold. The charge of the nuclei is x10 of the charge of the Carbon nuclei, so the inner electrons are x10 closer and the "speed" is x10 faster. [1] I don't remember the numbers, but some google search claims 2.7%c for Carbon and 58%c for Gold. You definitively can ignore the relativistic corrections at 2.7%c, there is a square somewhere in the formula and the corrections is like ~(1-(2.7/100)^2).
As the G...GP says, the problem are the weird parts of Quantum Mechanics that are ignored to get a fast method to get an approximation in DFT.
[1] There are some technical details to define "speed", but just squint your eyes and ignore the cries of physicist.