Quantum Meachanics; Normalization in 3D

joel.martens
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Homework Statement


(1) For the cubic 3D infinite-well wave function,
\psi(x,y,z) = A sin(n\pix/L)sin(n\piy/L)sin(n\piz/L)
Show that the correct normalization constant is A = (2/L)^{3/2}



Homework Equations


Note: The Pi's above are not meant to be superscript, and each n relates to the appropriate x,y,z
\int\psi*\psidx=1

The Attempt at a Solution


I have rearranged for A squared outside of the integral of the three sine functions (as a product) with limits of integration 0 to L. Not going to show it here becaus its long and messy. I am wondering if i need to do a triple (volume integration) or whether there is a shortcut because that's going to be one big, nasty integration :s
A little guidance would be appreciated,
Cheers, Joel.
 
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Your triple integral is the product of three single integrals, each of which is the same (except for the name of the dummy integration variable).
 
Ah, that's how it comes to root A cubed. Thankyou.
 
To solve this, I first used the units to work out that a= m* a/m, i.e. t=z/λ. This would allow you to determine the time duration within an interval section by section and then add this to the previous ones to obtain the age of the respective layer. However, this would require a constant thickness per year for each interval. However, since this is most likely not the case, my next consideration was that the age must be the integral of a 1/λ(z) function, which I cannot model.
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