indiana university p5751 dna diffraction. x-ray diffraction and biomolecular structure indiana...

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DNA Diffraction

X-ray diffraction and biomolecular structure

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DNA x-ray diffraction Diffraction by tungsten coil

Light is an electromagnetic wave:

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Diffraction Refraction

Hygens’ Principle:

Every point on a wavefront can be considered a secondary point source. Wavelets emitted by all points on the wavefront interfere with each other to produce the final traveling wave.

Diffraction of plane wave at large slit

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Diffraction of plane wave at small slit

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MIT Ripple Tank Demo

Water Waves

Superposition

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Superposition of sinusoidal waves

Single slit diffraction

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Alternations regions of high/low intensity:

Constructive/Destructive Interference

path length difference,

nconstructive

n destructive

(n = 0, 1, 2, …)

Double slit interference

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d sin = m constructive interference

d sin = (m+1/2) destructive interference

(m=0,1,2,….)

Diffraction grating

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Convolution, pictorially

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