On a diverse set with exp. refs. (black), ΔUKS (red/blue) beats SCS-CC2 for ΔE(ST) at a small fraction of the cost. Further, because it's so cheap, we can optimize (in solution!) and obtain accurate emission energies! Fresh from the press today in @acs.org JPCL: doi.org/10.1021/acs.... #compchem

Wave function methods like CC2/ADC(2) are accurate (also some DHDFs), but too slow to cover large search spaces in high throughout screenings.
This is where the state-specific ΔDFT/UKS developed in cooperation with @grimmelab.bsky.social really shines
(same for classic DA-TADF and INVEST emitters):

... achieves a small enough gap with the favorable properties of the mass-produced tDABNA.
A key challenge in the (re)search for the "eierlegende Wollmilch-DABNA" is the challenging electronic structure with short-range charge-transfer (SRCT) states, which cannot be modeled efficiently with TDDFT.

Multiresonance TADF emitters are almost perfect for #OLED: brilliant deep blue emission, stable, and volatile. If only their singlet-triplet gap ΔE(ST) was a little smaller, they could harvest triplets without the need for an Ir or Pt complex. However, none of the known permutations... #compchem🧶

This minimal (pre-dxTB) example showcases the power of this approach: By manually adapting a single (!) parameter, we made #GFN2 agree quantitatively CCSD(T) (from 2x overbinding!), which shed some light on the finite-temperature effects in an intriguing molecule: doi.org/10.1002/ange... (4)

#GFN2-xTB disrupted my #compchem workflows because it's 1000x faster than #DFT and general. Unfortunately, this comes at the cost of limited accuracy, but this is a choice. Any method can have only 2 of these 3: Accuracy (few kcal/mol), speed, and/or generality (applicable across chemical space) (1)