The following is a personal history of Professor Lothar Frommhold. He generously agreed to provide this write-up for the Physics Department History project. Additional material has been added by Mel Oakes with Professor Frommhold’s approval.
Lothar Werner Frommhold
It was Easter Sunday, 10 a.m. anno domini 1930 in Würzburg, Germany, when I was born as the third of four children of Karl Otto “Walter” Frommhold and his wife, Karolina, née Bernhardt. When I was three, the family moved to München, and five years later to Stuttgart, and finally to Hamburg, Germany, two months before the Second World War started in Europe. The picture at left consists of my oldest sister Rosmarie taking sister Hildegard and me for a walk in Würzburg about 1932. The picture at right, taken in the woods near München in about 1935, shows my father Walter and me in our traditional seppelhosen, mother Karolina in her dirndl and two of my three sisters, Hildegard (standing) and Margarete. (Oldest sister Rosmarie took the picture).
In these cities, I went to the local Volksschulen (elementary schools) like everybody else. In 1940, my teachers in consultation with my parents decided that I should go to an Oberrealschule, a typical German (or perhaps European) institution at the time where the teaching emphasis was on mathematics and science, though English, Latin and world literature were not neglected; options to drop any one of these subjects did not exist at any time. Most of my teachers there had a doctor’s degree in their field of specialization, and they knew what they tried to teach us more or less successfully. In 1943, when the bombing campaigns of the war started, mother took her three youngest children to the Bavarian countryside, where she grew up and where we could attend a similar school in a nearby small town until early spring of 1945, when the war ended.
In the first few months after the war, life in Bavaria was interesting —almost like a dream, I thought. 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. Nobody else seemed to be interested in such (for me) precious things. Anyway, in my various excursions to collect abandoned equipment, I never noticed anyone else picking up anything. It was there for me to take, and I collected as much as I could use immediately, as well as years later. I had some fun with gun powder 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. Where we lived in Bavaria there were no shops to buy anything, (besides I would not have had any money), but the forests seemed to offer everything I needed or wanted. 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.
With the limited budget I had in my earliest student days in Hamburg (before 1943), I had taken an interest in putting together simple radios (crystal detectors with LC tuning circuits) and single tube receivers with head phones for AM and short wave reception); in those early days, I had access to books in the public libraries which were good enough to teach me some basic knowledge which now, a few years later in Bavaria, was put to use. It was like a dream, all that wonderful, free, state of the art equipment, plentiful as it happened, to satisfy my curiosity (taking things apart) and to convert the plenty to simple radio receivers of slightly increasing sophistication, first for myself, but later also for Dad and some friends who wanted to listen to the radio.
In September 1945, the schools reopened, albeit with little or no heating in the fall and winter months. Class sizes were large an we were without textbooks or other learning materials. Most buildings were still in need of repairs. From the American military administration we received permission to move back to Hamburg where we shared our apartment, which was still standing, with another family not previously known to us, who was not so lucky. Anyway, we were happy that the worst was over and that a more or less normal life could begin to take its course. . .
With the help of various domestic and international institutions, including significantly the U.S. Marshall Plan, reconstruction of the German Universities proceeded slowly but steadily, so that after finishing school in 1950, I could enter the University of Hamburg to study mathematics and physics. That was new in the Frommhold family. Father was a commercial correspondent working in international trade and later became a leader in what I would describe as a white collar labor union (Deutsche Angestellten- Gewerkschaft or DAG). In the past, his family had known teachers, pastors, an artist painter, but certainly no physicist or technical professionals. Father’s colleagues, who certainly knew (or should have known) a lot about middle class job opportunities, inquired what his son was getting into and, after being told the truth, warned him that that was unwise and that I would never find a useful job to earn my keep. Fortunately, Dad did not listen (or, probably, he did listen, but decided differently) and I received my Diplom in February, 1956 (comparable to m.s. degree) and later the Doctor rerum naturalis in January of 1961 (comparable to Ph.D.), both from the University of Hamburg.
A few years later, 1964, I acquired along with my Habilitation (a kind of second doctor’s degree see below*) the venia legendi (the right to announce lectures at the University as a “Privatdozent”, a lecturer without pay). But even before the award of the doctor’s degree (and ever since) I had some income as a research associate at the Applied Physics Division of the University so that I was in a position to marry Fräulein Margarete Benz and we started our own family in 1958. Our son Sebastian was born in Germany in 1959 and daughter Caroline in Pittsburgh in 1965.
*(Dr. habil is a rare title, which qualifies one for an academic career at German (or some European) Universities, but without any promises for a professorship. The title grants one the venia legendi, the right to announce lectures at the University of Hamburg. The associated German title is Privatdozent ("privat" because nobody is paying you for your lectures). For the Dr. habil. title, one has to pass an oral examination before the whole faculty of the natural sciences, when a Dr. rer. nat. involves an examination by only four faculty members, mostly physicists. The time required for a Dr. habil. title, varies and may be as much as ten or twenty years in some cases of academic or industrial research. One has to be invited to apply.)
At the University of Hamburg, my teacher of quantum mechanics was Pascual Jordan, the former associate of Max Born and himself one of the pioneers of quantum mechanics. He attracted some of the best of my fellow students, but I was drawn more to another topic, specifically, electrical discharges in gases. At the time, this was a rather phenomenological and empirical field of study, but efforts were just beginning to better understand the fundamental atomic, molecular and ionic collision and reaction processes, such as electron attachment and detachment, molecular ion formations, etc. for a reasonably complete “microscopic” (or atomistic) descriptions of the phenomena. Fortunately, one of the first big digital computers was set up at the University, and I jumped on the opportunity to do some computations related to my doctoral work, which became now possible. My professor (Heinz Raether) encouraged me to talk to the director of the Computer Center, Prof. Lothar Collatz, to see if he could name an assistant of his whom we could hire to do the necessary programming. Prof. Collatz looked at me and said something like `Young man! As an aspiring scientist YOU program your work yourself! Besides, it is pretty simple—just the kind of thing every scientist can learn in minutes.’ Well, I am still learning a few things, but this was excellent advice at the right time. Digital computers have been an important device ever since for my whole career. . . In all the years since I have met quite a number of colleagues of my age or older who never learned much about programming and who have envied me for that advice which they were not given, or which they may have ignored at the time.
At that time, any research, which was more or less directly related to plasma physics, was still classified. However, at the universities around the world it became increasingly clearer that future progress of plasma research requires international collaboration—a feeling shared eventually by the governments and public figures. This led to the Geneva Conference, where all fundamental plasma research was internationally declassified in 1958.
My doctoral work on atomic processes and gaseous electronics attracted the attention of several American physicists, including Leonard Loeb at Berkeley, Manfred Biondi at the University of Pittsburgh and his famous (at the time) colleagues at the Westinghouse research facility, Art Phelps and George Schulz. In 1964, Fred Biondi (shown with me in the picture below) offered me a research position spectroscopically studying microwave afterglows. I accepted his offer, and we booked passage on the Polynnia for the trip from Hamburg to Norfolk, Va. The photo at right shows Margaret and me with son, Sebastian, solemnly peering down to the quay where a few good friends (not shown in the photo), were waving goodbye and offering a few last words of wisdom to us travelers prior to our departure. (The Polynnia was a freight ship, which once a month took a load of coal from Virginia to the electric power plant in Schulau near Hamburg. For the return trip to Norfolk, the freighter was empty, except for a few frugal passengers like us, who did not have much money to spend for the trip. We learned after a few years that the ship later broke into two pieces in the open Atlantic and it sank quickly.)
My two years at the University of Pittsburgh introduced me to American universities and research. Of course, we studied the main US scientific journals carefully during our student days in Germany, and later as aspiring young scientists. Still, it was fascinating to be right where all that beautiful work which impressed us was done.
I was immediately integrated in the ongoing research efforts. It was wonderful. Almost daily lunches with the immediate faculty, which was uplifting and inspiring, something unthinkable at the University of Hamburg. In Hamburg, my professor “supervised” more than hundred diplom and doctoral students. He was able to pay about ten of his older students (with doctor degrees) a salary and called them his “assistants”. I was one of them and supervised several students. Virtually all communication between student and professors had to go through the assistants. The assistants met once a week with the professor for an hour or so—that was all! The professor’s door was only for the professor to use; all others had to go to the secretary first and ask if they could talk to the professor. This is to be contrasted with the situation at the University of Pittsburgh where the professor’s door was nearly always open, and he would be a significant fraction of his time in the labs with the students. In short, in Hamburg the professor was a god-like figure not to be bothered if it could be helped, while in Pittsburgh we were colleagues with a common goal. And of course there were just a few graduate students in the lab, certainly not anything like a hundred. . .
In 1966, America was still very much in the post-Sputnik shock and in a newly discovered or rediscovered love affair with the sciences in the U.S., I was quickly hired as an associate professor in 1966 by Bill Robertson and Hans Schlüter at the University of Texas.
At the University of Texas, I first continued with studies of afterglows and negative ion reactions. When Dick Bernstein, with his incredible knowledge of the then current research activities in atomic and molecular physics arrived in Texas, he told me about the collision-induced, supermolecular Raman and infrared spectroscopies discovered in the fifties by Harry Welsh and associates in Toronto. I listened with interest and started to think about van der Waals molecules and supermolecular spectra of molecular collision pairs. With the help of the Joint Services, Electronics Program, I obtained an advanced double Raman spectrometer and an intense argon ion laser and set out in the early eighties to investigate the collision-induced Raman spectra of the rare gases. (Individual atoms, of course, do not possess Raman spectra, but collisional pairs of atoms acquire for the duration of the collision molecular properties, which was new and exciting at the time.) The R. A. Welch Foundation supported the work for many years. My feeling at the time was that few people understood what I was doing, and certainly not many cared much about it. This was my fault, of course, because I derived so much satisfaction from this rather rigorous work based on first principles of physics (the Schrödinger equation applied to molecular scattering events in the presence of photons) that I forgot to tell others about it, assuming naively that nobody could possibly miss such obvious beauty.
It was easy to extend the work to the infrared and there, it was very important for several current and significant applications by astronomers and planetary scientists. In short, many astronomical objects are known that consist significantly of hydrogen molecules and helium atoms. Neither H2 nor He are infrared active, but dense mixtures of hydrogen and helium gases are opaque in the infrared. Astronomers (and a few other spectroscopists) care because they want to model the atmospheres of solar and extra-solar planets, cool white dwarf stars, cool main sequence stars, and the so-called first stars. This is not possible unless one has reliable and accurate opacity data of mixtures of hydrogen and helium gases. With NSF support, we have provided such data over a wide range of frequencies and temperatures. We were asked to submit our extensive opacity tables to HITRAN, a well-known spectroscopic data base freely accessible to anybody in the world interested in using them.
Margaret Frommhold died in Austin, Texas, September 30, 2019.
Lothar, Margaret, Caroline and Sebastian Frommhold
Additional comments by Mel Oakes:
Some years ago Professor Alex Dalgarno, an editor of the prestigious Cambridge Monographs on Atomic, Molecular and Chemical Physics, asked Professor Frommhold if he would write the monograph about collision-induced absorption in gases for this series. He agreed and the book was published in 1994. A later edition became available in 2006 which is still the only monograph of the kind and is widely quoted.
Professor Frommhold is among that rare group of physicists who was at home in the laboratory or doing computations in his office. The early part of his career was devoted to experimental atomic physics. His knowledge, especially in the area of gas discharges, was highly appreciated by faculty and students who regularly sought his advice with their research problems. He generously and patiently provided solutions to both experimental and theoretical questions. Since atomic physics impacted directly or indirectly nearly all areas of physics, Professor Frommhold was considered an invaluable resource in the department as well as nationally and internationally. Later in his career he turned his attention to computational molecular physics and made many important contributions. Though he retired in 2011, he continues to be a productive scientist and shows no signs of slowing down.
Frommhold Photo Album