Ewald Construction-Solid State Physics-Presentation, Slides of Solid State Physics

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EWALD CONSTRUCTION

EWALD COSTRUCTION

THE EWALD CONSTRUCTION IS THE WAY TO

DRAW BRAGG’S LAW.

CRYSTALLOGRAPHERS USE IT TO VISUALIZE

WHICH RECIPROCAL LATTICE POINT WILL BE

IN DIFFRACTION CONDITION FOR A GIVEN

ORIENTATION OF THE CRYSTAL

STEP 2:

Draw a vector in the incident direction of length 2p/l terminating at the origin. This is an incident wave-

vector.

STEP 3:

Draw a vector from the origin of the incident wave- vector to the point of the intersection. This is reflected wave-vector.

STEP 5:

Draw a line perpendicular to the reciprocal lattice vector.

This line represents a reflecting plane.

Any crystal plane which is

parallel to that plane and

is spaced according to the

magnitude of the

reciprocal lattice vector

is participating in Bragg

reflection

STEP 6:

There usually is more than one point of

intersection of the circle with

the Bragg rod indicating

that there is more than

one plane which can

reflect the incident

beam according to

the Bragg law

Ewald construction

Ewald construction

THANKS