Richard Allan Ferrell, 79, an emeritus physics professor at the University of Maryland who researched nuclear and solid state physics, died Nov. 14 at his home in University Park. He had multiple myeloma.

Dr. Ferrell joined the U-Md. faculty in 1953, after completing a postdoctoral fellowship with German physicist Werner Heisenberg at the Max Planck Institute of Physics, then based in Goettingen, Germany.

Dr. Ferrell's initial interests were in nuclear physics and explaining why carbon-14 has a long half-life, a feature critical to its utility in carbon dating.

By the time he became a full professor in 1959, he began to focus on the tools of nuclear physics to study solids and liquids. He helped found and lead the condensed matter theory group in the physics department.

He also led the international group that uncovered general dynamical scaling principles, which were further developed by others and continue to be used today.

For the past few years, he studied cosmic strings -- an exotic form of matter of possible interest to astrophysicists.

He retired in 1993 but remained active in the department by maintaining research grant support and conducting research.

Dr. Ferrell was born in Santa Ana, Calif., and was a Navy veteran of World War II.

In the late 1940s, he received bachelor's and master's degrees in physics from the California Institute of Technology. In 1952, he received a doctorate in physics from Princeton University.

He published more than 150 journal articles and lectured and wrote in English, French, German and Russian.

Among other places, he took sabbatical leaves to the CERN laboratory in Geneva and the Max Planck Institutes in Munich and Stuttgart, Germany. He also participated in exchanges with Russian scientists.

His honors included the Sigma Xi scientific research society's award for scientific achievement.

He planted trees in University Park, and he successfully lobbied officials to have trees planted along U.S. Route 1 in College Park and on the U-Md. campus.

His avocations included skiing, hiking and bicycling.

Survivors include his wife of 53 years, Miriam Conover Ferrell of University Park; two children, Rebecca Wright of Fort Campbell, Ky., and Robert C. Ferrell of Santa Fe, N.M.; a sister; and three grandchildren.