Dale R. Schallhorn, 49, a research physicist with Harry Diamond Laboratories here, died Monday at Washington Hospital Center of injuries he had received in an car accident earlier that day. He lived in Takoma Park.

A spokesman for the Prince George's County police said Mr. Schallhorn was turning from Metzerott Road onto New Hampshire Avenue in Adelphi when he was struck by a van driven by John Harold Donovan, 29, of Adelphi. Police said Donovan's vehicle then jumped the median on New Hampshire Avenue, striking two other automobiles.

Donovan was charged with vehicular homicide, operating a motor vehicle while under the influence of alcohol, and failure to stop at a red light, police said. Donovan and the drivers of the other two cars were treated for injuries, the spokesman said.

Mr. Schallhorn came to this area in 1960 and worked for Harry Diamond Laboratories as a research physicist. From 1980 until his death, he was research manager for the laboratories.

Mr. Schallhorn was on the board of directors of the Harry Diamond Laboratories credit union. He was a member of Toastmasters International, holding the position of divisional lieutenant governor at the time of his death. He was a past member of both the Montgomery County Council of PTAs and the Piney Branch School. He was a past treasurer of Boy Scout Troop No. 33 in Takoma Park.

Mr. Schallhorn was a native of Kalamazoo, Mich. He was a 1960 graduate of Western Michigan University and earned his master's degree at the University of Maryland.

Survivors include his wife, Nancy, and a daughter, Peggy, both of Takoma Park; three sons, Brian, of Silver Spring, and Karl and Chris, both of Takoma Park; two sisters, Arlene Schallhorn of Tucson, Ariz., Marylou Hughson of Kalamazoo, and two brothers, William and David, both of Kalamazoo.