The present volume of conference proceedings contains selected papers presented during the 14th Polish Nationwide Seminar on Mössbauer Spectroscopy (OSSM'2026). The seminar took place in Złoty Potok from June 14 to 17, 2026, and was organized by the Department of Physics at the Częstochowa University of Technology. The seminar serves as a meeting point for the Polish scientific community engaged in Mössbauer spectroscopy and its applications across various fields of science and technology. The use of the Mössbauer effect for research purposes in Poland began in the 1960s, thanks to the initiative of Professor Andrzej Hrynkiewicz. Subsequently, numerous research groups specializing in Mössbauer spectroscopy were established in various cities across Poland. In 1996, thanks to the efforts and vision of Professors Mieczysław Budzyński and Elżbieta Jartych, the Lublin-based group initiated the Polish Seminars on Mössbauer Spectroscopy, which have since been held biennially at different academic centers.   

The seminar officially commenced with an inaugural lecture titled "Hyperfine interactions in compounds with a B20 crystal structure," delivered by Professor Mieczysław Budzyński. The 14th edition of the seminar brought together 40 scientists representing 12 research institutions. The program featured 17 oral presentations and a poster session. 

This volume of Acta Physica Polonica A includes 25 original research papers, selected from the material presented at the conference. The Scientific Committee and the Organizing Committe wish to express their gratitude to all participants for attending the seminar and for presenting the results of their research concerning topics in Mössbauer spectroscopy. 

Marcin Nabiałek
Bartłomiej Jeż 

Guest Editors of the Proceedings