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Glancing Angle X-ray Diffraction (GAXRD) Technique

Glancing Angle X-ray Diffraction (GAXRD) Technique

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Scattering contd..<br />

Collecting the relevant formulas for our purpose we get<br />

1 2<br />

ε '<br />

k'= ⎡ ⎤<br />

⎢⎣ε⎥⎦ k<br />

ε cosα = ε'cosα' Equation (1) is required by the Maxwell’s equations and (2) is<br />

Snell’s law (since the indices of refraction equal the square roots<br />

of the respective permittivity<br />

Amplitude of the refracted wave is linearly related to the amplitude<br />

of the incident , and is written as<br />

ur ur<br />

E ' =Φ.<br />

E<br />

where φ is a 2 nd rank tensor whose components can be expressed as<br />

Scattering contd..<br />

2 ( εε −ε<br />

1<br />

2 2 α )<br />

+ ( − )<br />

2 ' cos<br />

Φ = xx<br />

ε'sinα εε'ε cos α<br />

1<br />

2 2 2<br />

Eqs. (3) & (4), when expressed in more elementary terms<br />

for the separate cases of parallel and perpendicular<br />

polarization, are sometimes known as Fresnel’s equations<br />

(1)<br />

(2)<br />

(3)<br />

Φ yy =<br />

2 εsinα 1<br />

2 2<br />

εsinα + ( ε'−εcosα) 2εsinα Φ = zz<br />

1<br />

2 2 2<br />

ε'sinα + ( εε'−ε cos α)<br />

Φ =Φ =Φ =Φ =Φ =Φ = 0<br />

xy yx xz zx yz zy<br />

(4)<br />

7<br />

8

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