3 ms·

Hi again! I like https://github.com/PureStateLabs/sqd-spin-referee/blob/main/SUMMARY.md https://github.com/PureStateLabs/sqd-spin-referee/blob/main/... better,

Hi again! I like https://github.com/PureStateLabs/sqd-spin-referee/blob/main/SUMMARY.md https://github.com/PureStateLabs/sqd-spin-referee/blob/main/... better, the link at the top looks like standard AI generated stuff. Links to the previous posts: * https://news.ycombinator.com/item?id=49097083 https://news.ycombinator.com/item?id=49097083 (with my old comment) * https://news.ycombinator.com/item?id=49203707 https://news.ycombinator.com/item?id=49203707 (with an interesting comment by alpineidyll3) > [2Fe-2S] is two high-spin Fe(III) centres, each d5 with S = 5/2. I assumed S = 1/2 but a quick google search says that it may be 1/2 or 5/2. So it makes a lot of sense. > I've submitted the underlying paper here twice before as a Zenodo link, but it didn't get much discussion. There has been too much slop recently, I'm using a modified version of https://math.ucr.edu/home/baez/crackpot.html https://math.ucr.edu/home/baez/crackpot.html where you start at +5 instead of -5. Nature and Science adds -1. Zenodo adds +1. As I said before, this post makes sense. I'm still not sure it's correct and I didn't miss any detail, but it's not stupid-AI-slop.

purestatelabs 14d ago
Thanks for digging up the old threads. The 1/2 you found is the reduced cluster: one extra electron turns one iron into Fe(II) with S = 2, and 5/2 coupled antiparallel to 2 leaves 1/2. This model is the oxidized form, two Fe(III), so the two 5/2 spins pair to 0. That's why the target is a singlet. Something I should have said in the first comment: the 35-second script prints S^2 = 3.50, not 1.3711, because it runs on a small test space. The 1.3711 is from the full-size calculation, and re-checking that takes about 11 hours on a 64-core machine. Both are far from 0, but if you ran the quick one expecting 1.3711 it would look like it didn't reproduce. Fair point on the blog post. I'm going to rewrite it now. The summary's the better link until then.

purestatelabs 14d ago

Thanks for digging up the old threads. The 1/2 you found is the reduced cluster: one extra electron turns one iron into Fe(II) with S = 2, and 5/2 coupled antiparallel to 2 leaves 1/2. This model is the oxidized form, two Fe(III), so the two 5/2 spins pair to 0. That's why the target is a singlet. Something I should have said in the first comment: the 35-second script prints S^2 = 3.50, not 1.3711, because it runs on a small test space. The 1.3711 is from the full-size calculation, and re-checking that takes about 11 hours on a 64-core machine. Both are far from 0, but if you ran the quick one expecting 1.3711 it would look like it didn't reproduce. Fair point on the blog post. I'm going to rewrite it now. The summary's the better link until then.