WILLIAM HENRY BRAGG (1862-1942) WILLIAM LAWRENCE BRAGG (1890-1971)

1912 – England

WILLIAM HENRY BRAGG

X-rays scattered from a crystal will show constructive interference provided their wavelength ( λ ) fits the equation

2d sin θ = n λ 

where d is the spacing between atoms of the crystal, θ the angle through which the rays have scattered and n is any whole number

LAWRENCE BRAGG

This is the cornerstone of the science of X-ray crystallography.

TIMELINE

X-RAY DIFFRACTION

Symmetrically spaced atoms cause re-radiated X-rays to reinforce each other in the specific directions where their path-length difference, 2d sin θ, equals an integer multiple of the wavelength λ (Photo credit: Wikipedia)

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