formalism for going beyond the dipolar approximation

*ic1ion* is prepared to do calculations of the neutron cross section going beyond the dipole approximation for
the scattering cross section. The formulation of the scattering operator
implemented in the functions *mq* and *dncalc* have been given by Lovesey and Balcar [26], 6.87b:

(94) | |||

(95) | |||

(96) |

... these are the spherical components with , which are related to the cartesian components by

(97) | |||

(98) | |||

(99) |

The coefficients and are complex to obtain, formulas will not be given here, we refer the reader to [26] and just mention, that the computation involves of 3j, 6j and 9j symbols and some fractional parentage coefficients.

Martin Rotter 2017-01-10