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.
After his military service during WWII, Davis finished his undergraduate work at UCLA in 1947, pursuing 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 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.
At UC Berkeley Davis constructed a walk-in 15-foot-long spectrometer 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 frequently traveled to the National Solar Observatory at Kitt Peak, to collect laboratory data using their Fourier transform spectrometer. He coauthored the book 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 was, first and foremost, a consummate teacher: articulate and insightful, patient and empathetic. Joe Reader, a former student of Davis and now a director of the Atomic Spectroscopy Data Center at NIST in Gaithersburg, Maryland recalls: “Sumner always had an extremely positive attitude. When I told him that a vacuum pump I had built had exploded in the laboratory, he replied: "Well, now, we have to ask ourselves, what can we learn from this explosion?"” Restless after his retirement in 1993, Davis returned to UC Berkeley for another decade to direct the upper division physics teaching laboratory. He created dozens of videos explaining the various laboratory experiments, ranging from Zeeman spectroscopy to Josephson junctions.
Davis supervised 36 Ph.D.s during his career, many of whom became his lifelong friends. He would take his students bicycling through the Berkeley hills, and invite them to his home each Sunday evening to play music with other amateur musicians, with Davis playing (fairly respectable) oboe.
Davis learned to fly as a young man while in the Army Air Corps, and he remained an avid glider pilot into his 80s. As recently as 2000, Davis served as president of the Pacific Soaring Council, Inc. 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.
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 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 recent e-mail 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.”