Frequently asked Questions

-) How are comments denoted "#" or "#!" ?
Lines beginning with # are comment lines
Lines beginning with #! are also comment lines, but some programs will
      read information from these lines


-) are modules cfield and so1ion different ?

no, these modules do exactly the same job (as used with singleion).
However, if used as a module in mcphas, mcdisp etc the orientation
of the crystal field coordinate system xyz with respect to the crystal
axes abc is different:  for MODULE=so1ion it is xyz||abc, whereas for
MODULE=cfield it is xyz||cab


-) I  get the error message: "Error 1: Chreduce: matrix B is not positiv
definite" for some Q-vectors, what is going wrong ?

most probably the magnetic structure you are using in is not the
thermodynamically stable one. Try to rerun mcphas with less restrictions on
the test structures and try to find a structure with a lower free energy.
Probably the propagation vector of the stable magnetic structure is near
to the Q-vector, where mcdisp gave the error.


-) I cannot find ic1ion.mag after running ic1ion - what is the reason ?

Please be aware that on some windows systems the file extension ".mag" is associated
with other programs than mcphase and the explorer does not explicitely show the ".mag",
the file is there, you can make sure by listing the directory contents with the
command "dir"

-) The programs mcphas/mcdisp/chrgplt/charges/singleion will not load the
   module !?

check if the first line in your single ion input file (.sipf) points to the path
where the module can be found: e.g.

-) do I have to enter the free ion parameters F2 F4 F6 and XI in the sipf file ?

No, usually it is sufficient to give the IONTYPE, e.g. IONTYPE=Co3+ and then
the program automatically looks up F2 F4 F6 and XI in an internal table.
However, if you are not happy with the values from the table, you can explicitely enter
these constants. 
However for some ions these parameters are not available in standard tables, then
you have to enter them. Please always run ic1ion and check ic1ion.out to see if output 
is correct.

Martin Rotter 2017-01-10