Obituary: Professor Sir David Bates

David Robert Bates, mathematician and theoretical physicist: born Omagh, County Tyrone 18 November 1916; served Admiralty Research Laboratory 1939-41, Mine Design Department 1941-45; Lecturer in Mathematics, University College, London 1945-50, Reader in Physics 1951; Consultant, US Naval Ordnance Station, Injokern, California 1951; Professor of Applied Mathematics, Queen's University, Belfast 1951-68, Professor of Theoretical Physics 1968-74, Research Professor 1976-82 (Emeritus); FRS 1955; Kt 1978; Visiting Scholar in Atmospheric Sciences, Harvard University 1982-83; married 1956 Barbara Morris (one son, one daughter); died Belfast 5 January 1994.

DAVID BATES, the eminent theoretical physicist, was successively Professor of Applied Mathematics (1951-68) and of Theoretical Physics (1968-74) at Queen's University, Belfast.

Bates was born in the small town of Omagh, County Tyrone, in 1916. He was educated at the Royal Belfast Academical Institution and Queen's University, Belfast, where in 1937 he obtained First Class honours in mathematical and experimental physics. As a student he was stimulated by the superb lectures given by Harrie Massey and it was as a PhD student of Massey's that he developed his lifelong interest in theoretical atomicphysics.

In 1938 Bates moved to University College, London, where Massey had been appointed to the Goldsmid Chair of Mathematics. His studies were interrupted by the war when he went to work first in the Admiralty Research Laboratory at Teddington, where the main task was to protect ships against the menace of magnetic mines. He was later transferred to the Mine Design Department of HMS Vernon. In Peter Wright's controversial book Spycatcher Bates was described as one of the unsung heroes of the war.

After the war his career progressed rapidly. Back at University College, London, he was appointed a lecturer in 1945 and then a Reader in 1951. In 1951 he returned to Queen's University, where he held professorial posts - for the last six years as Research Professor - until his retirement in 1982. He became Professor of Theoretical Physics in 1968, and under Bates's leadership the department grew into a leading international centre for theoretical atomic physics.

The advent of quantum mechanics in the 1930s provided for the first time a firm basis for the calculation of rates of atomic and molecular processes such as excitation and ionisation of atoms, ions and molecules by protons, electrons and other atomic particles. Bates was a pioneer in the development of practical methods to calculate these rates and many of his methods are still in use today.

His basic work in theoretical atomic physics was stimulated by his intense interest in the application of these theoretical rates to the understanding of, for example, the earth's upper atmosphere, stellar atmospheres and, the interstellar medium and laboratory plasmas. His early work on the chemistry of the upper atmosphere forms the foundation for the present international studies of the depletion of the ozone layer and the effects of carbon dioxide on global warming. His work has also been put to great practical use in the modelling and understanding of large fusion plasmas such as JET (the Joint European Torus) which are being developed to produce a cheap source of energy.

During his long and distinguished career Bates was awarded many honours: he was a vice-president of the Royal Irish Academy, a Fellow of the Royal Society and in 1978 he was knighted for his services to science.

Bates also received important medals from the national and international science community. These include the Hughes Medal of the Royal Society, the Cree Medal of the Institute of Physics, the Gold Medal of the Royal Astronomical Society and the Fleming Medal of the American Geophysical Union. In 1992 the European Geophysical Society honoured him by establishing a new award - the Sir David Bates Medal - in recognition of his scientific achievements.

The high international standing of his work was acknowledged by his election as a member of the International Academy of Astronautics; a senior member of the International Academy of Quantum Molecular Science; an honorary foreign member of the American Academy of Arts and Sciences; an associate member of the Royal Academy of Belgium; and a foreign associate of the National Academy of Sciences in the US. He also received honorary degrees from nine universities.

Everyone who has lived in Northern Ireland during the last 25 years has been affected by the troubles. David Bates was not an exception to this. He took a keen interest in local politics and in 1971 became a founder member and vice-president of the moderate Alliance Party which has done much to heal divisions in Northern Ireland.

By nature David Bates was a kind man with a gentle humour, but capable of penetrating comments. He was a devoted hsuband, and also a modest man, and no doubt was dismayed in 1955 when a scientific proposal that he had put forward brought him into the public glare through popular newspaper publicity. He had compared the luminosity of the injection of sodium vapour into the upper atmosphere during the twilight period with the luminosity of the moon. Headlines shouted 'Artificial moonlight' or even worse 'Courting by artificial moonlight'.

The follow-up, when he married his wife Barbara in 1956, was even more embarrassing, as the headlines then blared, 'Moonlight professor weds in secret.'

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