Charles Alfred Coulson FRS FRSE (13 December 1910 – 7 January 1974) was a British applied mathematician and theoretical chemist.

[1][2][3][4] Coulson's major scientific work was as a pioneer of the application of the quantum theory of valency to problems of molecular structure, dynamics and reactivity.

[1] When the Coulson brothers were 10, their father was appointed Superintendent of Technical Colleges for the South-West of England, and the family moved to Bristol.

Coulson's academic success at Clifton earned him an Entrance Scholarship in Mathematics to Trinity College, Cambridge in 1928.

[citation needed] Coulson was accredited as a lay preacher in 1929, but he said his religion was perfunctory until a particular event in 1930, which he described in a documented sermon that he gave the following year.

His religious beliefs were influenced[2] by the physicist Sir Arthur Eddington, the theologian Charles Raven and, in particular,[8] by Alex(ander) Wood, Fellow of Emmanuel College, authority on acoustics[9] and pacifist,[10] and Labour parliamentary candidate.

Coulson collaborated with C. E. Duncanson at University College, London, brought George Stanley Rushbrooke from Cambridge and acted technically as his Ph.D. supervisor, and wrote the first edition of Waves.

It extolled his breadth of interests that took in the action of radiation on bacteria and the theory of liquids and solutions, besides the molecular orbital treatment of small molecules and ions, the approximation methods needed for large organic molecules for studies of bond lengths in coronene and conductivity of graphite, chemical reactivity, the treatment of momentum distribution functions and Compton-line profiles and his "well deserved reputation for his kindly and helpful encouragement of younger research workers.

"[13] Initially, Coulson's group were assigned offices on the top floor of a building (reached by a rickety wooden staircase) that overlooked the Strand, with considerable benefit when cavalcades paraded by on Lord Mayor's Day and Royal occasions.

[citation needed] In his account of the official opening of the new Physics Department, Maurice Wilkins wrote: "the theoretical group deals with applications of wave mechanics and statistical mechanics ... the theory of the chemical bond ... questions of chemical reactivity ... stability of crystal structures, biological properties of cancer-producing compounds and other molecules, electrical and magnetic properties of metals, ... properties of electrolytes and colloidal solutions, including ... electrophoresis ... more than one hundred papers have been published during the past five years.

The valence theory Ph.D. students included Simon J. Altmann, Michael P Barnett, Aagje Bozeman, Peter J. Davies, Harry H. Greenwood, Peter Higgs, Julianne Jacobs, Roland Lefebvre, George Lester, John Maddox, Norman H. March, and Robert Taylor.

On the institute website[15] Coulson is described as "a man who packed into his life twice as much as any normal academic person ... he had a gift for lucid exposition and was ... indefatigable in his work, not only for science and mathematics, but also on behalf of people, whether black or white, young or old.

In these, and in general interaction with people, he conveyed his religiosity in a gentle and sometimes humorous manner, for example, when he claimed in his inaugural lecture at King's College, that he had received mail addressed to him as Professor of Theological Physics.