David Leonard Chapman

Background

Chapman was born on December 6, 1869, in Wells-next-the-Sea, England, but moved with his family to Manchester.

Education

Chapman studied at Manchester Grammar School and Christ Church, Oxford, graduating in 1893 with first-class honors in chemistry.

Career

For ten years Chapman was on the staff at Owens College, Manchester, where he worked out the “Chapman equation,” interpreting theoretically the gaseous explosion rates being measured there by H. B. Dixon.

In 1907 Chapman was elected fellow at Jesus College, Oxford, where he taught, conducted research, and superintended the college laboratory until his retirement in 1944. He opened a new field by being the first to carry out rate measurements on a homogeneous gas reaction, the thermal decomposition of ozone. From this he turned to a lengthy study of the photochemical reaction between hydrogen and chlorine, which had given many workers trouble because of its variable behavior.

With his students Chapman showed that the mysterious “induction periods” observed were caused by minute traces of nitrogenous materials in the water used in the apparatus and was able to eliminate them. Next Chapman examined the kinetics and the inhibiting effect of oxygen. For hydrogen-chlorine mixtures of high purity contained in large vessels, he demonstrated that the reaction chain ended in bimolecular recombination of the carriers (chlorine atoms), by showing that rates were proportional to the square root of the light intensity. With hydrogen-bromine mixtures, which also follow the square-root law, he experimented with light interrupted by a variable-speed sector and was the first to work out the mathematical theory of the rate changes, which made it possible to estimate the lifetime of the bromine or chlorine atoms which acted as chain carriers.

Later, Chapman was interested in catalysis of gas reactions by metals; and during World War II some work for the “Tube Alloy” program (the British program to further development of an atom bomb) was carried out in his laboratory.

Achievements

• Chapman is associated with the Chapman-Jouguet treatment - on the theory of detonation in gases - and the Gouy-Chapman layer - the surface layer of ions distributed on a charged surface.

Membership

• Fellow

  Royal Society of London , United Kingdom

  1913

Personality

Campman was by reputation something of a scientific recluse, difficult to dislodge from his laboratory, although he did play a full part in University and College affairs. Away from his teaching and research, he was reserved and somewhat eccentric, but enjoyed golf, cycling and walking.

Interests

• Walking

• Sport & Clubs

  Golf, Cycling

Connections

Chapman married one of his research students, Muriel Holmes in 1918 and together they had a daughter, Ruth.

Spouse:

Muriel Holmes

Daughter:

Ruth Chapman

References

• Oxford Dictionary of National Biography
  2004
• Dictionary of Scientific Biography Volume 3
  1971