Walter Kohn

For the development of density functional theory (DFT). Building on the Hohenberg–Kohn theorem — which proved that the ground-state energy is a functional of the electron density $n(\mathbf{r})$ — Kohn and Lu Sham recast the many-electron problem into single-particle Kohn–Sham equations with an effective potential. DFT became the workhorse of computational chemistry, making electronic-structure calculations on large molecules and solids practical.