In Memoriam: Josef Paldus

Distinguished Professor Emeritus Josef Paldus passed away peacefully on Sunday January 15, 2023.

Prof. Paldus obtained his M.Sc. Degree in 1958 from the Faculty of Mathematics and Physics of the Charles University in Prague, Czechia, and his Ph.D. (CSc.) in 1961 from the Institute for Physical Chemistry of the Czechoslovak Academy of Sciences, the same year he married his lifetime partner, Eva.  From 1962 to 1964, he pursued his postdoctoral studies at the Division of Pure Physics of the National Research Council of Canada in Ottawa under the guidance of Dr. Don Ramsey and Dr. Gerhard Herzberg.

In 1968, after emigrating to Canada, he became an Associate Professor in the Department of Applied Mathematics at the fledgling University of Waterloo in Waterloo, Ontario, Canada.  Seven years later, he was promoted to Full Professor in both the Applied Mathematics and Chemistry Departments, and continued help build a world class department.  In 1984, he joined the Quantum Theory Project and also served as an Adjunct Professor in the Department of Chemistry at the University of Florida, Gainesville.  He was also the Associate Director of The Fields Institute for Research in Mathematical Sciences in Toronto, Ontario, Canada, from 1991 to 1994.  Until his death, he continued to serve as a Distinguished Professor Emeritus in the Quantum Theory Group, in the Department of Applied Mathematics at the University of Waterloo.

Prof. Paldus leaves behind a great body of work on coupled cluster theory, where he and Jiří Čížek adapted the many-body coupled cluster method to many-electron systems, thus making it a viable method in the study of the electronic correlation that occurs in atoms and molecules.   He was also well-known for his contributions to the Unitary Group Approach. This approach regards the computation of Hamiltonian matrix elements over N-electron spin eigenstates that appear in electronic correlation problems.

During his remarkable career spanning over 6 decades, he served as a Visiting Professor at several universities and research institutions in such countries as France, Germany, Italy, The Netherlands, and Israel, as well as organizing many international conferences and summer schools.  Amongst many international prizes and honors, he received honorary degrees from Charles University Prague, Bratislava, and Strasbourg, as well as becoming a Fellow of the Royal Society of Canada and the American Institute of Physics.   He also served as a member of numerous editorial and advisory boards of scientific journals in chemical physics, including the International Journal of Quantum Chemistry, Advances in Quantum Chemistry, Journal of Chemical Physics, Theoretica Chimica Acta, Journal of Mathematical Chemistry, and the Canadian Journal of Chemistry. 

A number of you will have known "Joe" as teacher, colleague, friend. He will be greatly missed and the world will not be the same without him.