This thesis deals with the numerical solution of the Boltzmann transport equation using an expansion of the distribution function in spherical harmonics for the purpose of electronic device simulation. Both the mathematical and physical backgrounds are discussed, then the Boltzmann transport equation is projected onto spherical harmonics without posing unnecessary restrictions on the energy ban...

The angular factors of atomic orbitals are real spherical harmonics. This is independent of the choice of basis function. In the course of molecular electronic structure calculations, numerous rotations of real spherical harmonics are required in a suitably defined space-fixed co-ordinate system. The origin and axes are space-fixed and rotation matrices defined on a basis of spherical harmonics...

Measurement of the angular power spectrum of the cosmic microwave background requires a spherical harmonic analysis of the observed temperature anisotropies. Even if all-sky maps are obtained, the region around the Galactic plane must be removed due to its strong microwave emissions, and the spherical harmonics are no longer orthonormal on the cut sky. An orthonormal basis set can be constructe...