Playing with HF exchange in DFT

Let me get this straight, it's a very bad idea to change the HF exchange in a functional, just in order to fit your expectation or the experimental results. But today, I'm going to do this horrible thing. The reason comes from this Watoc abstract from Burke et al. Basically, the authors claimed that For Fe(II)… Continue reading Playing with HF exchange in DFT

Adopting a new baby – v2RDM-CASSCF

In the previous post, I plan to use some "novel" multireference methods that can treat huge active spaces (up to 50 active orbitals). I now decide to adopt the first baby:  the variational two-electron reduced-density-matrix (2-RDM)-driven complete active space self consistent field (v2RDM-CASSCF). Why? Because Fun fact: in the paper, DePrince wrote “the chemistry community has… Continue reading Adopting a new baby – v2RDM-CASSCF

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)