As a single ion module, so1ion provides to mcphas the magnetic properties of a single rare earth ion subject to the crystal field. Its main duty is to calculate the magnetic moment given an effective magnetic field. To be more explicit - given the effective magnetic field by mcphas the module so1ion diagonalises the crystal field and Zeeman Hamiltonian (9) of the ion :
and calculates the expectation value of the angular momentum according to
(10) |
with
(11) | |||
(12) |
Here is the partition sum, the eigenstate corresponding to the eigenvalue of the Hamiltonian (9). 11