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// Scilab code Ex8.13: Bragg angle and the indices of diffraction of Powder Lines Page 285 (2010)
n = 1; // Cosider first order diffraction
a = 6e-010; // First lattice parameter of direct lattice, m
lambda = 1.54e-010; // Wavelength used in diffraction of X-rays by Powder Method, m
// Declare a function for converting angle into degrees and minutes
function [d,m] = degree_minute(n)
d = int(n);
m = (n-int(n))*60;
endfunction
// Calculate the hkl and hence interpalnar spacing 'd' for three lowest powder lines
printf("\nThe Bragg angles and the indices of diffraction for the three lowest powder lines are:");
for h = 0:1:2
for k = 0:1:2
for l = 0:1:1
if (modulo(h,2) == 1 & modulo(k,2) == 1 & modulo (l,2) == 1) | (modulo(h,2) == 0 & modulo(k,2) == 0 & modulo (l,2) == 0) then
if (h <> 0) then
N = h^2+k^2+l^2;
d = a/sqrt(N); // Interplanar spacing, metre
theta = asind(n*lambda/(2*d));
[deg, mint] = degree_minute(theta); // Call conversion function
printf("\nd[%d%d%d] = %4.2e and theta[%d%d%d] = %d deg %d min", h, k, l, d, h, k, l, deg, mint);
end
end
end
end
end
// Result
// The Bragg angles and the indices of diffraction for the three lowest powder lines are:
// d[111] = 3.46e-010 and theta[111] = 12 deg 50 min
// d[200] = 3.00e-010 and theta[200] = 14 deg 52 min
// d[220] = 2.12e-010 and theta[220] = 21 deg 17 min
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