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+// Scilab code Ex8.12: Reciprocal lattice parameters from 2-D direct lattice parameters Page 277 (2010)
+a = 3e-010;    // First lattice parameter of direct lattice
+b = 5e-010;    // Second lattice parameter of direct lattice
+theta = 60;    // Angle between two lattice vectors of the direct lattice
+// if a_prime and b_prime are the lattice vectors for the reciprocal lattice, then
+// a_prime*a = 2*%pi and a_prime*b = 0 
+// Similarly, b_prime*b = 2*%pi and b_prime*a = 0
+// Solving for a_prime and b_prime, we have
+a_prime = 2*%pi/(a*cosd(90-theta)); // Lattice vector for reciprocal lattice, per metre
+b_prime = 2*%pi/(b*cosd(90-theta)); // Lattice vector for reciprocal lattice, per metre
+printf("\nThe reciprocal lattice vectors are:\n a_prime = %5.2f per angstrom and b_prime = %5.2f per angstrom", a_prime*1e-010, b_prime*1e-010);
+// Result
+// The reciprocal lattice vectors are:
+// a_prime =  2.42 per angstrom and b_prime =  1.45 per angstrom
+\ No newline at end of file