Porter, George
George Porter, The Lord Porter of Luddenham
By David Phillips, CBE, FRS, Imperial College London.
George Porter, (Nobel Prize for Chemistry 1967) was the creator of flash photolysis and a world leader in the study of rapid chemical and biological processes. During his career at Cambridge, Sheffield, The Royal Institution, and Imperial College London he saw time resolution in fast reactions in chemistry and biology improve by 12 orders of magnitude.
George was born on 6th December 1920 in Stainforth, near Doncaster, UK, and was the only child of John Smith Porter, a builder, and Alice Ann, nee Roebuck. George attended Thorne Grammar School (where his father had been chair of the Governing Body), leaving in 1938 to read chemistry at Leeds University, graduating in 1941. In September 1941 he entered service with the Royal Naval Volunteer Reserve, serving in both the Mediterranean and Western Approaches theatres. In 1946, George Porter began his Ph.D. studies with RGW Norrish, FRS, with whom he was to share the Nobel Prize in 1967. The topic of the first work was the methylene radical, detected initially indirectly through the Paneth mirror technique, and thought at the time to be incapable of direct detection because of the short (10<math>^{-3}s>/math>) lifetime. George devised a method, approved of by Norrish and now known as flash photolysis, to detect the electronic absorption spectrum of the intermediate[1]. A second paper, published by Porter alone,[2] showed how these spectra could be recorded at different time delays, thus revealing the kinetics of decay processes, the true flash photolysis methodology.
Porter completed his Ph.D. in Cambridge in 1949, and stayed on as Demonstrator (1949-1952), and Assistant Director of Research in the Department of Physical Chemistry (1954-1956), and as Fellow of Emmanuel College (1952-54) and honorary fellow, 1967. During this time the time resolution of flash photolysis was reduced to microseconds, and Porter’s attention moved towards condensed-phase systems, including the recording of the triplet spectra of aromatic molecules (with Maurice Windsor) in solution.[3]
In 1954 Porter was Assistant Director of the British Rayon Research Association in Wythenshawe, Manchester, before moving to the University of Sheffield as their first Professor of Physical Chemistry. Here microsecond studies on a wide variety of molecules were extensive [4], but the time-scale of experiments was stalled, and did not reduce until Maiman’s development of the ruby laser in 1960. Porter’s group successfully used a Q-switch to the ruby laser, but the real exploitation came upon the move to the Royal Institution of Great Britain in London, where Porter became Director in 1966. He always said his nineteen years in this post were the happiest in his life, and certainly the research flourished, with the timescales progressing from sub-microsecond to nanosecond, and picosecond. The shortening of timescales was not a goal in itself, the research being driven by the need to study primary chemical events such as electron transfer, molecular rearrangements, dissociations and external processes such as energy transfer, molecular motions, diffusion etc which occur on these fast timescales. In his Bakerian lecture of the Royal Society [5] he outlined his work on the Z-scheme for plant photosynthesis, and the individual steps leading to charge separation and water splitting in Photosystem II. Light harvesting mechanisms in chloroplasts and algae were studied and the spatial arrangement of chromophores in which pigments of decreasing energy levels which funnelled the energy to the reaction centre elucidated. Artificial photosynthesis was also a primary goal of the work during these very productive years. The picosecond time regime is perhaps more remarkable for what cannot be observed than what can. Many physicalphenomena wereexpected to be revealed on the 10-9 to 10-11s timescale but were simply too rapid to be recorded, and this drove the development of the next phase of improvement of time-resolution , the femtosecond (10-15) regime firstly towards the end of Porter’s time at the Royal Institution, and then at Imperial College[6]. Porter had been elected as President of the Royal Society in 1985, and gave up his Directorship of the Royal Institution at the end of that year. Imperial College London offered him a home as Visiting Professor, firstly in Biology, and later in the Department of Chemistry. He ran a successful research group at Imperial, collaborating with James Barber in Biology/Biochemistry, and seeing two of his best research students David Klug and James Durrant gaining lectureships (now both having Chairs) in Chemistry at Imperial. He was still involved with research at Imperial College upon his death in 2002.
