qimpy.math.spherical_harmonics.get_harmonics_tilde

get_harmonics_tilde(l_max, G)

Same as get_harmonics(), but in reciprocal space. The result is a complex tensor containing \((iG)^l Y_{lm}(G)\), where the extra phase factor is from the Fourier transform of spherical harmonics. This is required for the corresponding real-space version to be real.

Parameters: