Over the past decade machine learning has made significant advances in approximating density functionals, but whether this signals end of human-designed functionals remains to be seen. Ryan Pederson, Bhupalee Kalita and Kieron Burke discuss rise for functional design.

The stacking mechanism of the 1H-4H proton transfer in 4-pyridone, 4-pyridinthione and p-aminopyridineare constructed. For quantitative description of this process by means of the quamtumchemicalmethod density functional theory (DFT) the activation energy (