Lothar Werner Frommhold

Lothar Werner Frommhold died 12 March 2021 in Austin, Texas.

Lothar was born on 20 April 1930, in Würzburg, Germany, to Karl Otto Walter and Karolina Bernhardt Frommhold. His father was a commercial correspondent working in international trade. After several moves the family arrived in Hamburg, where Lothar would receive most of his education. His teachers recognized his science and mathematical talents early, and at the age of 10 they urged his family to send him to an Oberrealschule, a school with emphasis in science and mathematics, however the classics were not neglected. His teachers had advanced degrees. In 1943, when the bombing of Hamburg started, his mother took Lothar and two of his younger siblings to the Bavarian countryside. He was able to continue his education in a village school until the war ended in 1945.

“In the first few months after the war, life in Bavaria was interesting—almost like a dream, I thought,” Lothar once described life after the war. “With the schools destroyed, I roamed the forests and found all sorts of leftovers of the war, such as more or less damaged electronic communication equipment of the defeated army, plenty of explosives and various, more or less, useful tools and devices. I had some fun with gunpowder, which was plentiful, but took a special interest in the radio equipment which I (more or less by myself) disassembled for parts, for building radios to listen to all sorts of broadcasts. Every piece of hardware, such as NiCad batteries and chargers, various types of radio valves (tubes), head phones and so forth, which one needed for that purpose, I scavenged from the woods and creeks. I even cut vacuum tubes open (there were many more available than I could possibly benefit from) to learn which electrode was connected to which pin of the socket, so that I actually could do my tinkering with the undocumented devices.”

After the family moved back to Hamburg, where universities had benefited from the Marshall Plan, Lothar, in 1950, entered the University of Hamburg. In 1958, Lothar married Margareta Benz. He received his Diplom in 1956, his Doctor rerum naturalis in 1961 and his Doctor habil in 1964 under the supervision of Heinz Raether. Lothar was taught quantum mechanics by Pascual Jordan.

Lothar’s doctoral work on atomic processes and gaseous electronics attracted the attention of Fred Biondi at the University of Pittsburgh, who offered him a research position spectroscopically studying microwave afterglows. In 1966 he was appointed associate professor at the University of Texas at Austin.

Richard B. Bernstein introduced Lothar to the collision-induced, supermolecular Raman and IR spectroscopies discovered in the 1950s by Harry Welsh and associates in Toronto. Lothar decided to investigate van der Waals molecules and supermolecular spectra of molecular collision pairs. In the early 1980s, with an advanced double Raman spectrometer and an intense argon ion laser, Lothar investigated the collision-induced Raman spectra of the rare gases. He extended the work to the IR, which attracted the attention of astronomers and planetary scientists. His extensive opacity tables for mixtures of hydrogen and helium gases were submitted to HITRAN, a well-known spectroscopic database.

In 1994, at the request of Alex Dalgarno, Lothar wrote a Cambridge monograph, Collision-induced absorption in gases. A second edition appeared in 2006.

Professor Frommhold was a kind and humble man, greatly respected and liked by his colleagues. He was equally at home in the laboratory and in theoretical and computational physics. He retired in 2010. His beloved wife, Margareta, died in 2019. They are survived by two children, Sebastian and Caroline.