X-ray Diffraction (XRD) fileWhat is X-ray Diffraction Bragg’s Law certain angles of incidence...

X-ray Diffraction (XRD)

X-rays production process

example

1) An electron in the K shell is ejected from the

atom by an external electron

X-rays production process

example

2)An electron from the L or M shell "jumps in“

to fill the vacancy. In the process,

it emits a characteristic x-ray

unique to this element and in turn,

produces a vacancy in the L or M shell.

Production of X-rays

Typical XRD Machine

Basic Features of Typical XRD

Experiment

What is X-ray Diffraction

� Bragg’s Law � certain angles of

incidence (theta ).

� The variable d is the

distance between atomic

layers in a crystal,

� and the variable λis the

wavelength of the

incident X-ray beam;

� n is an integer.

Constructive and Destructive

Interference of Waves

Deriving Bragg’s Law

How waves reveal the atomic structure of crystals

This observation is an

example of X-ray wave interference

It was direct evidence for the

periodic atomic structure of

crystals

Example of an X-ray powder

diffractogram produced

during an X-ray scan

Example of an X-ray powder

diffractogram produced

during an X-ray scan

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Why???

Why