Aleksander Jabłoński and the Brothers Vavilov on the 80th anniversary of the formulation of the Jabłoński diagram, 70th anniversary of the death of Nicolai Ivanovich Vavilov, and 62nd anniversary of the death of Sergei Ivanovich Vavilov

Abstract

A brief account of biographies of Aleksander Jabłoński and Sergei Ivanovich Vavilov – the pioneers in the development of the fields of contemporary molecular photophysics, photochemistry and photobiology – is given. In 1933, Jabłoński working at the Warsaw University suggested a diagram of energy levels of luminescent molecule, commonly known under his name, which makes it possible to explain the main features of photoluminescence phenomena such as fluorescence, delayed fluorescence and phosphorescence. Now, the Jabłoński diagram serves as the starting point of all modern textbooks on photochemistry and photobiology and is used as a basis for many scientific, medical and technological applications. As Jabłoński emphasized in his 1933 paper, the concept of his diagram is based on the results of experiments performed in Germany by H. Kautsky and in Soviet Union by S.I. Vavilov. In this article particular attention is focused on Vavilov’s research on various aspects of luminescence phenomena and its impact on the study made by Jabłoński. On the other hand, theoretical papers by Jabłoński on the polarization, quenching and decay of photoluminescence contributed to the progress of experiments in the Soviet laboratories led by S.I. Vavilov both in Moscow and in Leningrad. These two scholars met in person only once in May 1935 when Sergei I. Vavilov arrived to Warsaw and spent a week visiting and delivering seminars at the Physics Department of the Warsaw University. Vavilov was impressed very much by the results of measurements of the decay times of fluorescent components polarized parallel and perpendicular to the excitation light direction done by Jabłoński and his coworker Wacław Szymanowski. In consequence he initiated in Moscow extensive studies on the decay and polarization of luminescence of various materials which were stimulated by Jabłoński’s concepts. On September 17, 1939 Poland became attacked by the Soviet Union and the collaboration between S.I. Vavilov and A. Jabłoński was interrupted. In July 1940 Jabłoński as a Polish Army officer was arrested by Soviet authorities and transferred to an internment camp in Kozielsk. A part of this article deals with several unsuccessful attempts made by Jabłoński’s wife, Wiktoria, to release him from the camp. In particular, she wrote to Professor Sergei Vavilov – at that time the director of the Institute of Physics of the Academy of Sciences of the USSR – asking him for a help but she never received any answer. This topic is discussed in the article and it is concluded that even if Sergei Vavilov has received Wiktoria’s letter he could do nothing. On August 6, 1940 his brother Nicolai Ivanovich Vavilov, a prominent Soviet botanist and geneticist, and director of the Institute of Genetics was arrested and found guilty of sabotage of Soviet agriculture and spying for Great Britain. On July 9, 1941 he was sentenced to death. It was fated that Aleksander Jabłoński, a distinguished Polish scientist and Nicolai Vavilov, one of the most outstanding Soviet scholars – loyal to his country – have suffered at the same time from the Stalinist tyranny.