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External module function *dS1* - used by *mcdisp*

In order to visualize spin fluctuations and to calculate neutron intensities
in dipole approximation the external single ion module has to provide the transition
matrix elements of the spin by the
vector , which is given by:
.

The format to be used is:

extern "C" int dS1(int & tn,double & T,Vector & Hxc,Vector & Hext,double * g_J,Vector & MODPAR,
char ** sipffilename,ComplexVector & S1,float & maxE, ComplexMatrix & est)

The meaning of the symbols follows exactly that of function
*dm1* and therefore not explained here.

Martin Rotter
2017-01-10