Obituary of Sumner P. Davis

Physicist Sumner P. Davis, UC Berkeley spectroscopist and exemplary teacher

University of California, Berkeley physicist Sumner P. Davis, a beloved teacher whose research centered on the optical spectroscopy of diatomic molecules found in the sun and other stars, died Dec. 31, 2008 in El Cerrito, CA after a brief illness. He was 84.

Davis was a teenager when WWII broke out, and after his military service he finished his undergraduate work at UCLA in 1947, where he became interested in spectroscopy under the guidance of Joseph Ellis. Davis trained as a graduate student under molecular spectroscopist Francis Jenkins at UC Berkeley, where Davis used his ham radio expertise to construct an RF discharge to excite and analyze isotopes of diatomic selenium for his thesis. After receiving his Ph.D. from UC Berkeley, Davis went to MIT to postdoc under George Harrison, the premier artisan of finely-ruled diffraction gratings. In 1959, Jenkins invited Davis back to UC Berkeley to join the physics faculty, and Davis brought with him a highly prized gift – a diffraction grating presented to him by Harrison which Davis used for years to measure molecular spectra.

In the basement of Birge Hall at UC Berkeley, Davis constructed a 15-foot-long spectrometer that one could walk into, and he used it to produce detailed spectra of diatomic molecules of interest to astrophysics. With John G. Phillips he measured with high-precision the molecular constants of CN, C2, FeH, CS, SH and SiC2, TiO and others. Davis also studied the effect of the nuclear structure of Hg and Se on their optical spectra. He authored a book, Diffraction Grating Spectographs (1970), as well as monographs on CN and C2 spectra.

Davis branched into Fourier transform spectroscopy in 1976 and frequently traveled to the National Solar Observatory at Kitt Peak, near Tucson, Ariz., to collect laboratory data using their Fourier transform spectrometer. He coauthored a book on the subject, Fourier Transform Spectrometry (2001) with Mark C. Abrams and James Brault. In 1989, while returning to California after a long session on the spectrometer, his car, driven by Grace, his wife of 42 years, went off the road. Grace was killed but Sumner survived.

Sumner Davis’ priorities included, first and foremost, a love of teaching. He received a Distinguished Teaching Award from UC Berkeley in 1980. Davis was the consummate teacher: articulate and insightful, patient and empathetic. He knew how to deal with all kinds of people; when to take a stand, when to offer help, when to crack the whip, when to have a good laugh. Restless after his retirement in 1993, Davis returned to UC Berkeley for another 10 years to direct the upper division physics teaching laboratory. He created over two dozen videos explaining the various experiments in the laboratory, ranging from Zeeman spectroscopy to Josephson junctions. (He even wore a tie in some of them.) Those videos are still in use and can be accessed at http://socrates.berkeley.edu/~phylabs/adv/index.html

Davis supervised 36 Ph.D.s during his career, many of whom became his lifelong friends. He loved to build things, including a harpsichord, and he would invite his students to his home each Sunday evening to play music with other amateur musicians, with Davis playing (fairly respectable) oboe. He would also take his students bicycling through the Berkeley hills. He made his students feel that they were part of his family.

“Sumner was a favorite of the students and a very good teacher,” said Joe Reader, who was a student of Davis’s in the 1960s and is now director of the Atomic Spectroscopy Data Center at the National Institute of Standards and Technology in Gaithersburg, Md. “He always had an extremely positive attitude.” Reader recalled Sumner’s reaction when told that a vacuum pump Reader had built exploded in the laboratory: “Well, now, we have to ask ourselves, what can we learn from this explosion?”

Davis pursued kayaking and drove a convertible sports car into his late 70s. He learned to fly as a young man while in the Army Air Corps, and he remained an avid glider pilot into his 80s. He always offered his graduate students a ride in his glider, and Davis and his glider were pictured in National Geographic magazine after achieving an altitude record of 10,000+ feet over Arizona. As recently as 2000, Davis served as president of the Pacific Soaring Council, Inc., an organization devoted to furthering the education and development of soaring pilots.

He was a fellow of the American Physical Society and the Optical Society of America, and a member of the American Astronomical Society and the American Association of Physics Teachers. Upon his retirement, he received the Berkeley Citation. He was a NATO Senior Fellow in Science in 1967 and twice was a visiting astronomer at the National Solar Observatory in Kitt Peak.

Davis is survived by his wife, Robin Free, of El Cerrito, CA, who remarked, “He was like a 10-year-old boy. Every morning he would wake up and think, what adventures am I going to have today?” His e-mail to one of us from a few years ago sums up his spirit:

“My desktop has been down for a week, and I am snowed with e-mail and behind on a few other things. Otherwise, all is well. We had 11 Chinese educators visit us, to look over all the labs. As I started to introduce our advanced lab, I put on my academic gown and a large conical wizard’s cap, and told them how wizardry is necessary even in scientific Physics laboratories. I then made a pass through the lab rooms in my tie-dyed lab coat and the cat’s hat from Dr. Seuss’s Cat in the Hat. Got a few high fives from the students. The hat is now resting on the head of large giraffe in my office.”