- #1
mcodesmart
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I am studying Solid state physics from kittel and I am stuck at the following equation. I can see that the exponential term turns to the kroneckler delta, but I don't understand how the integral gives the volume of the specimen, Ω? What am I not seeing?
∫d3x f(x)eiK.x = [itex]\sum[/itex] aG∫d3x ei(K+G).x = Ω[itex]\sum[/itex]aGδk,-G
f(x) is the Fourier transform of the lattice, ie. the reciprocal lattice and he wants to prove that integration is not zero unless k is a vector in the reciprocal lattice G
∫d3x f(x)eiK.x = [itex]\sum[/itex] aG∫d3x ei(K+G).x = Ω[itex]\sum[/itex]aGδk,-G
f(x) is the Fourier transform of the lattice, ie. the reciprocal lattice and he wants to prove that integration is not zero unless k is a vector in the reciprocal lattice G