Second cumulant of the electron density

A functional can get the energy right and still get the electron density wrong. This benchmark judges DFT on the density itself, comparing dipole moments, quadrupole moments, and the density’s overall spread (the second cumulant) against CCSD(T) references across small molecules and radicals.

This repository is the pipeline behind the paper: Q-Chem inputs and raw outputs from the HPC runs, extraction scripts, a versioned JSON document store holding 4,630 calculation records across 93 species, and the analysis notebook that produced the tables, figures, and functional rankings.

It began as my undergraduate research in the Head-Gordon group at Berkeley and became an equal-contribution first-author paper with Diptarka Hait.