Robert Parr

Robert Ghormley Parr (September 22, 1921 – March 27, 2017) was an American theoretical chemist who was a professor of chemistry at the University of North Carolina at Chapel Hill.

Working with DuPont chemist Rudolph Pariser, Parr developed a method of computing approximate molecular orbitals for pi electron systems, published in 1953.

By 1978 Parr had realized that density functional theory (DFT) would be extremely useful in quantitative calculations of chemical and biological systems, especially those with high molecular weights.

In 1988 Parr, Weitao Yang and Chengteh Lee produced an improved DFT method which could approximate the correlation energy of systems.

In 1989 he and Yang published Density Functional Theory of Atoms and Molecules, now considered the basic textbook on DFT.