THEO_ENERGIES

THEO_ENERGIES can be defined to set the electron energy range on which the reference calculation, as well as the search algorithm will be performed.

Default: if no experimental data file is available, THEO_ENERGIES = 20 800 3, otherwise THEO_ENERGIES = Efrom Eto 3, with Efrom = min(exp. energy) - 3 and Eto = max(exp. energy) + 3

Syntax:

THEO_ENERGIES = 20 600 3
THEO_ENERGIES = 50
THEO_ENERGIES = _ _ 2   ! get Efrom and Eto from experimental data, but use step 2 eV

Acceptable values: Three positive floats for explicit definition, OR one float to calculate only one energy, OR use underscores to leave some values but not others at default (e.g. to be defined by experimental beams).

Notice that, generally, it is a good idea to choose the start and end energies such that the theoretical calculation interval is a few eV larger than the experimental energy range. During the determination of the $R$ factors, as well as in the search of the best structure, the theoretical spectra will be shifted a bit along the energy axis to find the best match with experiment (see IV_SHIFT_RANGE to control this shift).

If Eto - Efrom is not an integer multiple of Estep, Efrom will be modified to a slightly lower energy such that this is the case.