On 16 February 2026, the Polish physics community suffered a painful loss – professor Jan Żylicz, an outstanding nuclear physicist, passed away in Warsaw.
Jan Lubart Żylicz was born on 7 January 1932 in Góra, in the Kashubian region, and completed his studies in physics at the University of Warsaw in 1955, under the supervision of Andrzej Sołtan. His work on beta spectroscopy of strongly deformed nuclei, conducted at the Institute of Nuclear Research, contributed to his 1961 PhD at the University of Warsaw. He continued his research on beta decay of rare-earth nuclei during a stay at the Niels Bohr Institute in Copenhagen from 1963 to 1965. One of his important contributions was the identification of the Coriolis effect’s role in rotating atomic nuclei, which served as the basis for his habilitation at the University of Warsaw in 1967.
His research stay at the CERN–ISOLDE facility, from 1970 to 1971, was devoted to the study of nuclides far from beta stability. This topic significantly influenced his subsequent scientific work, and he spent two further research stays in the mass separator group at GSI Darmstadt, from 1978 to 1979 and from 1986 to 1987. The close and long-lasting collaboration with GSI, which Jan initiated, played a crucial role in the scientific development of young scientists in the Warsaw group, many of whom completed postdoctoral fellowships there.
He led several large research projects, including studies of octupole correlations in actinide nuclei. This work was to some extent pioneering and contributed to growing interest in this topic among theorists and experimentalists. He devoted particular attention to exotic nuclides far from the beta-stability line, notably through the extensive research programme on Gamow–Teller transitions in the region of the doubly magic tin isotope 100Sn, carried out mainly at GSI Darmstadt, but also at the ILL in Grenoble, the University of Jyväskylä and CERN–ISOLDE.
Jan had a talent for initiating valuable research programmes that could be carried out in Poland under the modest experimental conditions available in Warsaw at the end of communism. For example, he developed a new method for measuring the K-shell ionisation by charged particles, which was used for many years at the Warsaw Van de Graaff accelerator and yielded several results of practical importance. He was also interested in phenomena at the interface between nuclear and atomic physics, and proposed a programme to study radiative electron capture in forbidden transitions. Among Jan’s most original achievements are his works on the isomeric state of 229Th, and the idea of spin-mixing oscillations in the states of the hydrogen-like ion 229Th89+. This work was ahead of its time – attempts to confirm the phenomena he predicted are currently underway at the ESR storage ring at GSI Darmstadt.
Associated with the University of Warsaw from 1972 to the end of his career, Jan established a new Nuclear Spectroscopy Group, which he headed until 1994, and served as director of the Institute of Experimental Physics from 1994 to 2002. In 2005, the Polish Physical Society awarded him its highest distinction – the Marian Smoluchowski Medal – and the European Physical Society honoured him with the title of EPS Fellow. He was also awarded the Knight’s Cross of the Order of Polonia Restituta.
Jan was an outstanding educator, whose lectures were valued for their clarity and for the passion with which he explained the essence of a problem. He attached particular importance to mentoring young academic staff, supporting and patiently motivating them. He sent them to international conferences and helped to organise research stays at leading Western institutions, which was especially important at a time when this was not as easy as it is today. He supervised 17 master’s theses and 12 doctoral dissertations, with six of his students later becoming professors of physics. Their successes brought him joy and pride, and he considered creating the conditions for the scientific development of his younger colleagues his principal achievement.
Jan Żylicz was a warm and kind man with an extraordinary sense of humour. Working with him gave us a sense of purpose, satisfaction and joy. He will forever be remembered as a model scholar and teacher.
