In 1998, Freeman left Lawrence Livermore National Laboratory and joined University of California, Davis, where he held positions of chair and Edward Teller Professor at Department of Engineering Applied Science till 2003.
During his term at Ohio State University, he served as dean of College of Math and Physical Sciences from 2003 through 2007,[6] as head of the high energy density research group and as the first director of the SCARLET laser facility.
Freeman focused on the energy level systematics of high-angular-momentum Rydberg states of alkali-metal atoms and described them through a quantum-defect model.
He then presented the mechanisms responsible for the resulting difference and also discussed the applications of constraints regarding obtaining electron energy distributions from experimental data.
[14] Freeman developed a method involving detection of ionization products, for measuring peak intensity at the focus of high energy short pulse lasers operating in single shot mode.
[15] He conducted a combined study of particle-in-cell and Monte Carlo modeling and investigated the production of Bremsstrahlung radiation during the interaction of ultra-intense laser with a tower-structured target.
Freeman’s research indicated that the backward-going, high-energy electrons interacting with the focusing optic resulted in the generation of energetic x-rays in the experiment.