{Piret Kuusk - Institute of Physics,University of Tartu, Indrek Martinson - Institute of Physics, Lund University, mansucript}

Introduction

Over the years  we  have written several papers about  Estonian physicists who had to leave their country in late 1944 when Soviet Union was occupying Estonia.    Estonia was an independent and democratic country between 1918 and 1940. As a result of the secret Molotov-Ribbentrop pact in August 1939, Estonia was included in the Soviet sphere of influence and was occupied by the Soviet Union in June 1940. About 60, 000 Estonians disappeared during the following 13 months. In June 1941  Nazi Germany attacked the Soviet Union, and Estonia was occupied by Germany. This occupation lasted until September 1944. During those three years about 25, 000 Estonians disappeared. As Germany gradually withdrew,  the Baltic countries were occupied by the Red Army. In September 1944 about 70,000 Estonians fled their homeland, hoping to settle in democratic countries after the war.

These papers, in Estonian, have appeared in the yearbook of the Estonian Physics Society. In the latest yearbook, issued in  February 2005 our article is about  three distinguished scientists, Hinrek Neuhaus, Uuno Öpik and Olev Mathiesen. Neuhaus and Mathiesen live in Sweden while Öpik lived in UK. In early 2005 we were in contact with them, by telephone conversations  and electronic mails  and they received the yearbook in March 2005. In May 2005 we heard that Uuno Öpik had died. He had  colleagues and friends in UK and other countries, and we therefore translated  the section in our article which describes Uuno’s life and work from Estonian into  English. The article was written for general physicists, also including high-school teachers and physics students.  

Uuno Öpik

Uuno Öpik was born on October 19, 1926 in Tartu, Estonia. His father was the famous astronomer Ernst Öpik  (1893-1985). Uuno graduated from the First high School in Tartu in 1943 and moved with his parents and sister to Germany in the fall of 1944.  He told us that :  ”The refugees from the Baltic countries who were university professors were well received in Germany and their stay there was  well organized.   Our family stayed   in Danzig,  Swinemünde (now  Gdansk and Swinouijsie) and in  Sielbeck-Uklei (in Schleswig-Holstein). From January 1 1945 till the end of the war I worked  in the   Hamburg-Bergedorf Observatory and made numerical calculations”. In 1946 he  became a student at the Baltic University  .(initially in  Hamburg and later in Pinneberg)   and studied there until the spring of 1948. In the following summer .the Öpik family moved to Northern Ireland and Uuno continued his studies at   the Queens’s University of Belfast.  He graduated in 1950 with a BSc in mathematics  and in 1951 with a BSc in physics.  Uuno got his PhD in 1954, at the same university, with the thesis  “Quantal investigations of certain excitation and ionization processes”.  He worked as a research assistant at the University of Bristol   1955-56, while between    1956 and 1960 he was a lecturer at the   University College,  Wales. He then returned to the Queen’s University in Belfast, being there a lecturer (1962-68) and reader (1968-1986).However, he. spent the academic year 1965-66. at the Oak Ridge National Laboratory, USA.   Uuno Öpik’s  field of research was basically theoretical atomic physics. He  did not only study atomic structure but also ion-atom collisions. In some remarkable papers he investigated the core polarization effects in atoms and ions     [1, 2].

These two papers have been of considerable interest to  experimental atomic spectroscopists who frequently study such effects.   Öpik also investigated  the charge-exchange process in atomic collisions, particularly  between a neutral atom and an ion. Here one has to apply the time-dependent Schrödinger equation, which can be complicated, in particular when several   electrons are involved    Together with  H.G. Morrison Uuno developed a new method  in which the wavefunction can be developed into a large number of basis functions. The latter are accurately defined in order  to describe the movement of one electron between two nuclei  [3].   By using this theory it was first possible to describe  the collisions between He2+ and  H, thereby finding that theory and experiment were in excellent agreement. The authors then extended their formalism  to collisions between  H+  and  H  [4], and even for this relatively simple system they significantly improved previous theories. Some years later Morrison and Öpik hade further developed their theory and there  now existed a beautiful agreement between theory and elaborate but also very time-consuming and quite difficult experiments [5].   Most of the later work was now  carried out by Öpik , because Morrison was working as a high school teacher and later in the Pedagogics department of the university. Thus he had no time to continue the work with the program. Detailed information about this sophisticated  program was published in 1993   [6] .  In January 2005 Öpik told us  that  with  present-day computers it should not be difficult to obtain truly accurate theoretical results with their programs, but he believed that nobody had tried that.

During the year at the Oak Ridge laboratory   Öpik  was involved in solid state theory. Together with R.F. Wood he studied the electronic structure and point defects  of ionic crystals, for example  KCl, KBr, KI  and NaCl [7-9]. The authors showed that dielectronic polarization is an important factor which must be included in the theoretical work to reach  agreement with experimental data. It is of course well known that the scientists  at the Institute of Physics, Tartu University, are performing thorough studies  such crystals, primarily by means of experimental techniques, but also theoretically.    

Uuno Öpik now lives in Melksham, a small town in southern England, not far from Bristol or Bath  He is interested in music,  he sings in the local chorus,  often attends  concerts and plays the piano at home.

Uuno’s son,  Lembit Öpik, born in 1965   is a member of the UK Parliament  and represents the Liberal Party.

References

Final remarks

While working with this article we had some telephone conversations with Uuno Öpik and also  got several letters from him.

In January 14  he sent some reprints of his papers  and told us a little about his father’s scientific career.   In the following letter,  January 19, .  he briefly described his life as a refugee in Germany  1944-48, and  answered a question about his collaboration with  Dr, H.G. Morrison  on charge transfer and excitation (Papers  3-6, above). This information was included in our paper.  In his last letter, from February 9, he mentioned that his Ph D thesis adviser had been Sir David  Bates  while Sir Harrie Massey  had been  the external examiner.  Some weeks later, probably in early April,  one of us (IM) had a short telephone conversation with him. It was difficult to hear what he said, except that he liked the article.  On May 3 a letter came from his wife Ene Öpik who told us thet Uuno had died on April 30. She added that his  disease “Motor   Neurone Disease”  had developed very rapidly  and at the end  he  could not breathe (The letter was in Estonian). .