Charlotte Froese Fischer (born 1929) is a Canadian-American applied mathematician and computer scientist noted for the development and implementation of the Multi-Configurational Hartree–Fock (MCHF) approach to atomic-structure calculations and its application to the description of atomic structure and spectra. The experimental discovery of the negative ion of calcium was motivated by her theoretical prediction of its existence. This was the first known anion of a Group 2 element. Its discovery was cited in Froese Fischer's election to Fellow of the American Physical Society. Early life Charlotte Froese was born on September 21, 1929, in the village of Stara Mykolaivka (formerly Pravdivka, and Nikolayevka), in the Donetsk region, in the present-day Ukraine, to parents of Mennonite descent. Her parents immigrated to Germany in 1929 on the last train allowed to cross the border before its closure by Soviet authorities. After a few months in a refugee camp, her family was allowed to immigrate to Canada, where they eventually established themselves in Chilliwack, British Columbia. Education and research She obtained both a B.A. degree, with honors, in Mathematics and Chemistry and an M.A. degree in Applied Mathematics from the University of British Columbia in 1952 and 1954, respectively. She then obtained her Ph.D. in Applied Mathematics and Computing at Cambridge University in 1957, pursuing coursework in quantum theory with Paul Dirac. She worked under the supervision of Douglas Hartree, whom she assisted in programming the Electronic Delay Storage Automatic Calculator (EDSAC) for atomic-structure calculations. She served on the mathematics faculty of the University of British Columbia from 1957 till 1968, where she introduced numerical analysis and computer courses into the curriculum and was instrumental in the formation of the Computer Science Department.Froese Fischer spent 1963-64 at the Harvard College Observatory, where she extended her research on atomic-structure calculations. While at Harvard, she was the first woman scientist to be awarded an Alfred P. Sloan Fellowship. In 1991 she became a Fellow of the American Physical Society, in part for her contribution to the discovery of negative calcium. In 1995 she was elected a member of the Royal Physiographic Society in Lund, in 2004 a foreign member of the Lithuanian Academy of Sciences, and in 2015 she was awarded an Honorary Doctorate in Technology from Malmö University, Sweden. Contributions Froese Fischer is the author of over 300 research articles on computational atomic theory, many of which have had far-reaching impact in the area