Charlotte Froese Fischer

Charlotte Froese Fischer, professor emerita at several universities and a Fellow of the American Physical Society, passed away on 8 February 2024. She was a pioneer in the field of atomic structure calculations, which she pushed into new dimensions by developing state-of-the-art computer programs to solve the multiconfiguration Hartree–Fock and Dirac–Fock equations for complex atoms and ions. Subsequently, she used the solutions to predict measurable quantities such as energy levels and transition probabilities.

Charlotte Froese was born on 21 September 1929 in the village of Nikolayevka (later Pravdivka, now Stara Mykolaivka), Donetsk region, Ukraine. After spending some time in a refugee camp in Germany in 1929, she and her parents immigrated to Canada, eventually settling in British Columbia. Charlotte was the first in her family to attend university; she obtained BA degrees in mathematics and chemistry and an MA degree in applied mathematics from the University of British Columbia in 1952 and 1954, respectively. She received her PhD in applied mathematics and computing in 1957 from Cambridge University (UK), where she pursued coursework in quantum theory with Paul Dirac.

Charlotte worked on her PhD under the supervision of Douglas R. Hartree, and she quickly became a world-renowned expert on numerical methods, with particular emphasis on applications to atomic structure calculations. From 1957 until 1969, she moved through the ranks from instructor to professor in the mathematics department at the University of British Columbia, followed by professorships at the University of Waterloo (Canada), Pennsylvania State University, and Vanderbilt University, where she retired from her regular duties as a faculty member in 1996. Charlotte never gave up her passion for science and continued active research until her last days. Among many short- and long-term visits to various institutions, she held a guest researcher position in the Atomic Spectroscopy Group at NIST beginning in 2005.

With more than 22 000 citations, Charlotte is the highest-cited researcher on Google Scholar in the field of computational atomic physics. Her books The Hartree–Fock Method For Atoms: A Numerical Approach and Computational Atomic Structure: An MCHF Approach (with T. Brage and P. Jönsson) are must-reads for anybody interested in the field. Her computer programs are widely used to produce benchmark data (energy levels, oscillator strengths) that are needed on their own for the interpretation of many laboratory and astrophysical spectra and, equally important, as input for dynamical calculations such as photoionization and electron-induced collision processes. Charlotte was always ready to help her colleagues, and she was very passionate in educating the next generations of scientists to fill her big scientific shoes. She was very active as a member of the international collaboration of Computation of Atomic Structure (CompAS) and the Atomic, Molecular, and Optical Science (AMOS) Gateway.

Charlotte received many honors, including fellowships in several professional societies and honorary doctorates from Malmö University in Sweden and Western University in Canada. She was the first woman to be awarded an Alfred P. Sloan Fellowship, she received a Fulbright Senior Research Award from the Benelux countries, and she was a Foreign Member of the Lithuanian Academy of Science.

Charlotte was preceded in death by her husband, Patrick C. Fischer, also a noted computer scientist. She is survived by her daughter Carolyn Fischer, an environmental economist and research manager at the World Bank. Charlotte was a generous supporter of several universities, STEM programs, and nature conservation. She will be dearly missed by her family and her many friends and colleagues.

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