Inga Fischer-Hjalmars was a Swedish chemist and a theoretical physician. She was the first woman to be appointed professor of theoretical physics in Sweden.

Inga Fischer-Hjalmars was born in Stockholm in 1918. Both of her parents were well-educated but despite this the family suffered periodically from financial difficulties. This limited Inga Fischer-Hjalmars’ opportunities for higher education. She was able to gain her school-leaving certificate after receiving financial support from her relatives in Denmark. As she wanted to continue into further education she had to choose the shortest scientific programme that was available, namely the two-year pharmaceutical course.

Pharmaceutical sciences proved to be a clever choice as it led to good employment prospects. This enabled Inga Fischer-Hjalmars to continue studying chemistry whilst she worked. Her intention in studying chemistry was to become a teacher but during her studies she was exposed to different sections of the chemical research environment in Stockholm and this led her onto the scientific path.

Whilst studying chemistry Inga Fischer-Hjalmars worked as an assistant for the biochemist and Nobel Prize winner Hans von Euler-Chelpin. In his laboratory some of the work she participated in included quintessential studies on the differences in cell nuclei between healthy versus cancer cells.

A large part of Inga Fischer-Hjalmars’ early scientific education came from another research environment, namely from within the group led by Nils Löfgren. This group had discovered the local anaesthetic Xylocain in the early 1940s. Inga Fischer-Hjalmars played a central role in the early development of Xylocain and contributed to a deeper understanding of the physiological functions of the medicine.

During Inga Fischer-Hjalmar’s period as part of Nils Löfgren’s group she developed an interest in chemistry and particularly for its physical origins. Her experimental work in the second half of the 1940s mainly involved different forms of interaction between molecules. In order to deepen her knowledge of the underlying principles of chemistry she continued her physics studies during this period and came to know Oskar Klein, the theoretical physician. Inga Fischer-Hjalmars became a close friend of Klein and of his family. Oskar Klein piqued Inga Fischer-Hjalmars’ interest in the possible application of quantum mechanics to chemistry and in what was then a relatively young scientific field of quantum chemistry.

Arne Tiselius, a Nobel Prize winner and member of the research council, noted Inga Fischer-Hjalmars’ talent and understood that her interest in quantum chemistry was hardly shared in Sweden towards the end of the 1940s. Encouraged by Tiselius, Inga Fischer-Hjalmars travelled to Paris in the spring of 1948 in order to participate in a conference. She attended the conference in the hopes of finding a mentor and someone who could teach her quantum chemistry and its methodology. The conference was attended by a range of prominent researchers in the area and in the end the individual who became her mentor was an Englishman called Charles Coulson. Inga Fischer-Hjalmars spent the winter of 1948-1949 with Coulson at King’s College in London.

Charles Coulson’s view of theoretical chemistry and its role within science influenced Inga Fischer-Hjalmars’ future efforts in the field. Coulson believed that the role of theoretical chemistry was not just to reduce physical chemistry to quantum mechanics, but that an equally important role for the new field of quantum mechanics was its application to questions of pure chemistry and in thus contribute to increased understanding within all areas of chemistry.

In 1952 Inga Fischer-Hjalmars defended her thesis entitled Studies of the hydrogen bond and the ortho-effect. This was an unusual thesis in that it contained both theoretical and experimental work. That same year Inga Fischer-Hjalmars married Stig Hjalmars.

The core issue of quantum chemistry is to find solutions to the Schrödinger equation for molecules. Much of Inga Fischer-Hjalmars’ early work comprised critical analyses of the contemporary methods which existed to achieve that end. She often investigated what limitations there were in the methodology and worked consistently to defeat them. As a theoretician she did not just work at a conceptual level, but often made close comparisons with experimental results for the molecules which she studied. Inga Fischer-Hjalmars quickly became internationally renowned within theoretical chemistry and her fellow research contemporaries often made use of her work, even just after she had obtained her doctorate.

In 1963 Inga Fischer-Hjalmars succeeded her former teacher and mentor Oskar Klein and thus became the first woman in Sweden to be appointed professor of theoretical physics. Given her background as a pharmacist and considering that her main research interest lay in chemical rather than physical matters, this was an extremely remarkable appointment.

Towards the end of the 1960s Inga Fischer-Hjalmars began to take an interest in the precision of contemporary semi-empirical variants of the molecular orbital method and the approximations which lay at its basis. This work led, in the 1970s, to the development of improved semi-empirical methods which allowed for quantum mechanical computations on more complex molecules and heavier atoms, such as transition metals. The latter part of Inga Fischer-Hjalmars’ research was largely devoted to studies regarding the binding and electron structure of biomolecules. In 1985 Inga Fischer-Hjalmars was awarded the International Society of Quantum Biology Award for her quantum chemical studies of biomolecules.

During the 1970s Inga Fischer-Hjalmars also contributed to the semi-classic distribution theory which was applied to simple chemical reactions. During the 1980s she worked with her husband, Stig Hjalmars, on solid-state physics and also investigated the continuum description of crystals.

Inga Fischer-Hjalmars was very active in human rights and in particular in the freedom and rights of researchers from the Soviet Union. She was supportive of the so-called refuseniks, that is, individuals in the Soviet Union who were not allowed to emigrate or even leave their home state temporarily, thus hampering these researchers’ opportunities to be part of the international developments within their research field. During the 1980s Inga Fischer-Hjalmars served as the chair of Committee of Free Circulation of Scientists, a committee which aimed to protect the freedom of movement of researchers who were members of the International Council of Scientific Union (ICSU). As chair she brought the attention of the international community to the problems of the Soviet Union and at every given opportunity she applied pressure to the Soviet academy of sciences. In addition to this public engagement Inga Fischer-Hjalmars was also active in unofficial efforts to help improve conditions for Soviet colleagues. She undertook many trips to the Soviet Union with the intention of exchanging knowledge and experience with the isolated researchers there, and to supply them with material resources and medicines. For these activities Inga Fischer-Hjalmars was awarded the Heinz R. Pagels Human Rights of Scientists Award by the New York Academy of Sciences in 1990. She also was one of the founders of the Svenska Helsingforskommittén för mänskliga rättigheter (Swedish Helsinki committee for human rights).

In 1978 Inga Fischer-Hjalmars was elected into the Kungliga Vetenskapsakademi (royal academy of sciences) and served as its vice-president from 1982-1985. She was elected into the International Academy of Quantum Molecular Science in 1983.

Inga Fischer-Hjalmars, along with Per-Olov Löwdin in Uppsala, was one of the founders of the Swedish school of theoretical chemistry. Inga Fischer-Hjalmars educated, both directly and indirectly, an entire generation of theoretical chemists in Sweden, including Björn Roos, Per Siegbahn, and Margareta Blomberg.

Inga Fischer-Hjalmars died in 2008. She was then 90 years old. The Svenska kemisamfund (Swedish chemistry society) has since 2010 made an annual award to the most promising doctorate within theoretical chemistry, named the Inga Fischer-Hjalmars Award.