Rodney Joseph Bartlett (born March 31, 1944, in Memphis, Tennessee, U.S.) is Graduate Research Professor of Chemistry and Physics, University of Florida, Gainesville, US.
Bartlett was an NDEA and IBM predoctoral fellow at the University of Florida under the joint supervision of N. Yngve Öhrn and Per-Olov Löwdin.
He developed a version of Feynman diagrams that both expedited the derivation of the equations and helped to visualize the physics of electron correlation.
He also promoted the concept of size extensivity for many-body theory that scales properly with the number of particles, now viewed as an essential element of sound quantum chemistry approximations.
It is now widely agreed that the coupled cluster and many-body perturbation methods that Bartlett has been instrumental in establishing offer the most predictive, generally applicable approaches in the field.