Density functional theory: Wisdom of the crowd – GGA functionals

In the previous post, I used a bunch of LDA functionals to study the hydrogen bond in the water dimer. The idea is quite simple but unique and "novel": combine different exchange and correlation functionals and take an average result. In this post, I update the result with nearly 4000 GGA functionals. Let's discuss A… Continue reading Density functional theory: Wisdom of the crowd – GGA functionals

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Minnesota MN15 functional (and the others) – new challenge

As an attention seeker, I want to have more and more views for my blog. And you know what, the number of views of the MN15 posts (or DFT in general) is way higher than the other WFT posts. So today, I write (again) on MN15 and the other modern functionals. Of course, I will… Continue reading Minnesota MN15 functional (and the others) – new challenge

Minnesota MN15 functional (and the others) – magnetic coupling constant – a benchmark study

Honestly, I don't like studying magnetic systems, e.g. single molecule magnet, and I don't know why I end up testing my three favorite functionals with this toy model H-He-H. You may laugh at this system but there has been at least 6 papers (six!, including one from Gustavo E. Scuseria) used this system as a model… Continue reading Minnesota MN15 functional (and the others) – magnetic coupling constant – a benchmark study

Minnesota MN15 functional (and the others) – SIE!

One of the main "feature" of Kohn-Sham DFT (KS-DFT) is the approximation of the exact exchange-correlation functional, leading to a zoo of functionals with many flaws. One such flaw is the self-interaction error (SIE), i.e. an electron can interact with itself! Reducing SIE is one of the goal when "designing" a new modern functional (by… Continue reading Minnesota MN15 functional (and the others) – SIE!

Minnesota MN15 functional (and the others) – part 3

It's sunny today, so I decided to perform just a small test (and spend the rest of my day staying outside) again with MN15, SCAN0, and ωB97M-V. The molecule is small, Fe(CO)4, inspired from the work of Harvey et al. (here and here). In these works, the authors studied the singlet-triplet gap ΔE = E(LS)… Continue reading Minnesota MN15 functional (and the others) – part 3

Minnesota MN15 functional (and the others) – an update

Thanks to the author of Erkale: The bug with SCAN0 is fixed. My calculation with Erkale is now faster. I should have included the computational details with Erkale: e.g. DFTGrid(75,302), or default Cholesky decomposition for the two-electron integrals (produce an error of ~1 kcal/mol). So here, this is a small update of my previous post (remember I… Continue reading Minnesota MN15 functional (and the others) – an update

Minnesota MN15 functional (and the others)

See a small update here. Last year I was at the 8th MQM conference and attended a talk of D. Truhlar advertising his latest Minnesota functional, the MN15 functional. According to his talk, this functional is good at describing everything, including multireference problems. I was quite skeptical of that. Last week, one of my colleagues… Continue reading Minnesota MN15 functional (and the others)