Description of mlayer input parameters:
=======================================


 Schematic representation of the multilayer:

               vacuum
    |------------------------------|  \
    |          odd (1)             |  |
    |------------------------------|  | BILAYER # n_bilayers
    |          even (2)            |  |
    |------------------------------|  /
    |          .                   |
    |          .                   |
    |          .                   |
    |------------------------------|  \
    |          odd (2n - 1)        |  |
    |------------------------------|  | BILAYER # 1
    |          even (2n)           |  |
    |------------------------------|  /
    |                              |
    |///////// substrate //////////|
    |                              |



LAYER PERIODICITY: Multilayer may be periodic or aperiodic. In the first 
  case you may define the number of layer pairs and the thickness of the 
  two components of the pair. In the second case you must prepare a file 
  containing two columns and N rows, one row for each pair.
  The first element of the column is the thickness in A of the odd element and 
  the second column is the thickness of the even element.

SCANNING VARIABLE: Grazing angle [deg] or Photon Energy [eV]

MATERIAL PARAMETERS: 
	Create on the fly: the material parameters are created by mlayer
                     and placed in a file mlayer.f12 (which overwrites previous
                     versions).
        Use existing file: mlayer.f12:  Do not create the mlayer.f12 file 
                     and uses an existing one. 
                     The mlayer.f12 file created "on the fly" can be edited by 
                     hand customize the materials, optical constants, 
                     densities, etc.
                     
                     ****Note that the file mlayer.f12 is overwritten when the 
                     "Material parameters" entry is set to "Create on the fly".
                     
SUBSTRATE: Chemical symbol for the substrate.

ODD LAYER MATERIAL's chemical symbol for the odd layer

EVEN LAYER MATERIAL's chemical symbol for the even layer

PHOTON ENERGY: in eV

GRAZING ANGLE: in degrees

SCANNING VARIABLE STEP: the spep in either Photon energy or grazing angle, 
  depending on your choice.

NUMBER OF SCANNING POINTS: obvious.

THICKNESS FOR THE ODD MATERIAL in A, when periodic Mlayers are considered.

THICKNESS FOR THE EVEN MATERIAL in A, when periodic Mlayers are considered.

NUMBER OF LAYER PAIRS when periodic Mlayers are considered.

FILE WITH LAYER THICKNESSES: file name with thicknesses as explained before, 
  valid only when Individual layers are considered.