Rappal Sangameswaraier Krishnan
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Rappal Sangameswaraier Krishnan (1911–1999) is an Indian scientist and researcher.
[edit] Overview
Krishnan was born near Palghat, Kerala on 22 September 1911. He completed his school education in Palghat, being consistently at the top of his class. Winning a small scholarship, he joined the St. Joseph’s College, Tiruchirapalli, for his B Sc (Hons) degree in Physics, where also he obtained first rank. After completing this in 1933, he joined C.V.Raman as a research student in the newly started Department of Physics, IISc, Bangalore. The early batch of research scholars had, apart from R. S. Krishnan himself, persons like N. S.Nagendra Nath, C. S. Venkateswaran and others, all of whom rose to be leading members of the physics community, getting elected to various academies and winning various awards/distinctions in due course.
In his personal life, Krishnan was simple, strict and religious. He had his likes and dislikes about which he made no pretenses. He belonged to the earlier era of scientific research and administrative procedures and yet he succeeded in making a smooth transition to the new age. He was active and in good health until May of 2005, when his health began to fail. He is survived by his wife, who had been a pillar of strength to him for more than six decades, his two sons and three daughters.
[edit] Research
Krishnan’s early studies were on the scattering of light by colloidal solutions. In the course of these investigations, he discovered the reciprocal relation between the intensity of the horizontally polarized incident light getting scattered with vertical polarization and the intensity of the vertically polarized incident light getting scattered with horizontal polarization, irrespective of the nature of the colloidal particles. This was called Krishnan’s reciprocity effect and formed the basis for getting his D Sc degree from the University of Madras.
In 1938 he was awarded the Overseas Scholarship of the Royal Commission for the Exhibition of 1851 and went to the University of Cambridge to work with Sir John Cockcroft. There he was the first to observe the deuteron-induced fission in uranium and thorium.
He returned to IISc ( Indian Institute of Science ) in 1941, when the Second World War had already begun. Homi J. Bhabha also returned from Cambridge at about the same time as the Reader of Physics in IISc and started work on cosmic rays and theoretical physics. With severe financial crunch due to the War, Krishnan, as a Lecturer of Physics (1942–1945), started work on the Raman spectra of crystalline materials. The use of the ultraviolet 2537 Å resonance radiation, using the mercury arc lamps made locally with fused quartz envelopes, was an unusual and path-breaking experimental innovation. The source was powerful and in the scattered light the incident wavelength could be suppressed by the resonance absorption of the 2537 Å light by a small amount of mercury vapour. This development enabled Krishnan to record the second-order Raman spectra in diamond and in alkali halide crystals. The experiments triggered a series of investigations in many laboratories and provided the first confirmation of the lattice dynamics model of crystals. The Brillouin scattering from several crystals was also studied, in particular the subtle new phenomena which occur in the scattering from birefringent and optically active crystals. Krishnan was made an Assistant Professor in 1945 and was appointed to be the Professor and Head of the Department in 1948, when Raman retired from that post.
In the post-war period, Krishnan energetically developed the department into an active school of research in crystal physics. G. N. Ramachandran and S. Ramaseshan, who had earlier started their work with C. V. Raman, made outstanding contributions to crystal optics, thermo-physical properties of crystals and X-ray crystallography. Newer colleagues like P. S. Narayanan, G. Suryan, P. T. Narasimhan and V. S. Venkatesubramanian started in the early fifties to open out new areas like nuclear geochronology, magnetic resonance, dielectrics/ferroelectrics and ultrasonics.
Studies on semiconductors were added soon as also work on low temperature physics and theoretical solid state physics. The department attracted very good students from all over India, who got imbibed into the spirit of building and developing one’s own apparatus or experimental facilities. Though the hierarchical ladder of the student/assistant, Lecturer, Assistant Professor and the all-powerful Professor was the norm in those days, Krishnan gave considerable freedom to the younger colleagues to grow on their own, training them not only in research but also in administrative responsibilities. It is therefore not surprising that several persons of this period made names for themselves later on, both as distinguished Professors of Physics and also as Directors of various institutions. In spite of a temporary cloud arising out of an unfortunate litigation against IISc in 1961/1962, Krishnan continued to be very active in the department till his formal retirement in 1972.
Soon after superannuating from the services of the IISc, Krishnan became the Vice Chancellor of the University of Kerala, Thiruvananthapuram (1973– 1977), where he tried to link the University with the work being done in the Space Research Center (now called Vikram Sarabhai Space Centere). He then returned to Bangalore and undertook the collection, annotation and editing of the scientific publications on Raman Effect under a DST sponsored programme (Source Book on Raman Effect: First volume, pre-1937 period, second volume, 1937– 1948, and third volume, 1948–1961 the beginning of the laser revolution). These volumes and the earlier book on Crystal Physics, including in addition crystal physics property data, have been widely used by many scholars. Krishnan published over 220 papers in scientific journals and over 60 students had taken their Ph Ds with him.
He was elected, among others, to the Fellowship of the Indian Academy of Sciences in 1944, to the National Institute of Sciences, India (now called Indian National Science Academy) in 1950, the Institute of Physics (UK) in 1953 and the American Physical Society in 1955. He had traveled widely in India and abroad not only in his personal professional capacity but also as a member of many national committees/delegations. Among the many awards and medals he had received, the Sir C. V. Raman Centenary Medal and the IISc Platinum Jubilee Alumni Award probably gave him maximum pleasure and satisfaction.
