I came to Prof. Perfiliev’s laboratory as a student at the beginning of 1994 and continued to collaborate with him until the very last days. From the very beginning, Prof. Perfiliev received me very warmly. He was always tolerant of youthful antics (and over time he passed this quality on to me). Prof. Perfiliev always helped me in any way he could, and sometimes he was the only one who stood up for me in scientific disputes and life situations.

Prof. Perfiliev's scientific activity was almost entirely devoted to Mössbauer spectroscopy. I was always amazed by Prof. Perfiliev's story about his first mechanically driven Mössbauer spectrometer. The spectrometer turned out to be huge, and the vibration during measurements shook the floor. Perhaps, that is why Prof. Perfiliev was the first at the Department who began working with an electrodynamic spectrometer. In those early years, when Mössbauer spectroscopy was just beginning to develop, everything, to one degree or another, had to be done by ourselves: spectrometers, sources, detectors, cryostats, etc. Therefore, Prof. Perfiliev was a person who knew all the experimental aspects of the method and was always ready to share this knowledge.

Prof. Perfiliev established and for more than 20 years headed the Laboratory of Nuclear Chemical Techniques of the Division of Radiochemistry of the Department of Chemistry of Moscow State University. He always treated his laboratory with care and paid great attention to its material support. In the difficult 1990s, three spectrometers worked in the laboratory, sources and isotopes were received. Prof. Perfiliev enthusiastically purchased experimental equipment. In 1995, the laboratory received the constant-velocities spectrometer (Perseus), a unique domestic development that has no analogues in the world. For more than 20 years, Prof. Perfiliev maintained this device in working condition. Prof. Perfiliev generally always welcomed any technical innovations, tried to help in their production and implementation, and was calm about failures and losses.

Many amazing chemical experiments were carried out in Prof. Perfiliev's laboratory. Prof. Perfiliev always provided experimental liberty and tried to find opportunities to support even those experiments whose prospects were in question.

I think, that all the Mössbauer scientists in the Soviet Union were familiar with Prof. Perfiliev. Half of the people I met at Russian national Mössbauer conferences were among the guests of the laboratory. Prof. Perfiliev also had many friends and colleagues abroad. Prof. Perfiliev's laboratory participated in a number of international projects. For many years, Prof. Perfiliev was associate editor of the Mossbauer Effect Reference and Data Journal.

Prof. Perfiliev left a large, friendly family. He was always very proud of his two sons and grandchildren. In the recent years, Prof. Perfiliev began to actively research his ancestry, looking for the graves of ancestors buried before the October Revolution (1917), and looking for living relatives. He told many amazing stories about this.

Until his very last days, Yurii Dmitrievich Perfiliev remained an active scientist and an optimistic, cheerful person with a sober outlook on life and a wonderful sense of humor. This is how I will remember him!

Sergey Dedushenko

Moscow