Varley Fullerton Sears (born 1937, died at age 81 in Deep River, Ontario on June 9, 2019) was a Canadian physicist, notable for his contributions to the methodological foundations of neutron scattering.
In 1960, Sears obtained a Ph.D. from the University of Toronto with a thesis on The rotational absorption spectrum of solid and liquid parahydrogen. From 1963 to 1965, the National Research Council of Canada sent him as an Overseas Postdoctoral Fellow to the Clarendon Laboratory in Oxford where he was hosted by Roger James Elliott and worked on Raman scattering by semiconductors. Back in Canada, he became a staff scientist in the Theoretical Physics Branch of Chalk River Laboratories. In 1966/67, he published seminal papers on neutron spectra of molecular rotors.VF Sears Can. J. Phys. 44, 1279 (1966), ibid 44, 1299 (1966), ibid 45, 237 (1967). By the 1980s, he had become a leading expert in neutron optics, publishing a review and a textbookVF Sears 1989: Neutron optics: an introduction to the theory of neutron optical phenomena and their applications - Oxford University Press. Review by Anton Zeilinger at http://scitation.aip.org/content/aip/magazine/physicstoday/article/43/7/10.1063/1.2810631. on the subject. Based on these foundations, he compiled authoritative tables of neutron scattering lengths.VF Sears 1984, Thermal-neutron scattering lengths and cross sections for condensed-matter research - Atomic Energy of Canada Ltd., Chalk River, Ontario. Chalk River Nuclear Labs.VF Sears 1986, Neutron Scattering Lengths and Cross Sections in Methods in Experimental Physics Volume 23A, pp 521–550. In 1997, he published a generic solution of the Darwin-Hamilton equations that provide an approximative description of multiple Bragg reflection by a mosaic crystal.VF Sears 1997 Acta Crystallogr A53, 35-45.
He was elected a Fellow of the American Physical Society in 1990.
References
Obituary: Neutron News 30 (4) 16 (2020).