William R. (“Bill”) Brennen, emeritus associate professor of chemistry, died November 9. He was 83.

Dr. Brennen, who earned his PhD in chemistry from Harvard, joined the chemistry faculty at Penn in 1966 as an assistant professor of chemistry. He was promoted to associate professor in 1970, which he remained until retirement in 2005, at which time he earned emeritus status.

Dr. Brennen was the principal investigator of a 1970 project Excitation of Atomic Nickel in the Reaction Between Nickel Carbonyl and Active Nitrogen, sponsored by the Advanced Research Projects Agency of the US Department of Commerce. He served on the University Council’s Bookstore Committee from 1996 to 1999 and from 1997 to 1999 he served on the Library Committee.

Dr. Brennen is survived by his wife, Sherry Clearwater; sons, William Jr. (“Bill”) and Spencer; stepson, Jamie Vagnoni (Julie Crowe); and grandchildren, Quinn and Kate Vagnoni.