1. The problem statement, all variables and given/known data I want to expand sin(theta) in spherical harmonics. Well, actually I want (3cos^2(theta+45°)-1)*exp(i*(psi+45°)) but I think I could find my mistake by the above simple example. 2. Relevant equations http://en.wikipedia.org/wiki/Spherical_harmonics 3. The attempt at a solution I seem to get zero for all coefficients by the integrals from wikipedia. Can I not expand along an arbitrary axis?