This is a description of the input parameters for xpowder/Calc reflections

WAVELENGTH: The photon wavelength in Amstrongs

LIMIT REFLECTIONS BY: Define the number of reflections calculated by 
	one of the following values: the maximum 2theta, the min of
        d-spacing, or the max h=k=l value. 

VALUE: The numerical value as defined above. 

TEMPERATURE FACTOR: Three possibilites:
       1) Enter the exp(-M) value (a positive value between 0 and 1)
       2) Enter the absolute temperatute in Kelvin, WITH A MINUS SIGN.
	  The minus sign tells to the code that the number entered
	  refers to a temperature and not to the full debye-waller exp(-M)
	  factor. The minus sign will not be considered for the numerial
	  calculations. 
	  In this case, the Debye-Waller factor is calculated 
	  as a function of the temperature, using a well-known approximation 
	  as a function of sin(theta/lambda)=1/(2d), temperature, atomic 
	  mass and Debye-temperature. In the case of crystal structures 
	  with more that one atomic sites, an independent Debye-Waller 
	  factor is calculated for each atomic site and then putting them 
	  together by averaging the M's. Values for atomic mass and 
	  Debye temperatures are obtained from the DABAX file
	  AtomicConstants.dat. For more info, see the documentation in the
	  function DebyeWaller.pro
       3) Enter a question mark (?). 
	  In this case, the code will perform the calculation as in 
	  point 2), but it will pop-up a window that will permit to modify 
	  the Debye-Waller ingredients (i.e., the sin(theta/lambda)=1/(2d) 
	  ratio, temperatute, atomic mass and Debye temperature). 
	  In the case of crystal structures with several atomic types, 
	  several values of atomic mass and Debye temperature should be entered.
	  The default values are taken from the DABAX file AtomicConstants.dat. 
	  The interest of this option is to allow the user to "improve"
	  the default value of the temperature factor, which is 
	  mostly "structure" dependent rather than dependent on the atomic 
	  types. For example, in the case of AlphaQuartz (SiO2), The Debye 
	  temperature of the oxygen is not defined by default in the 
	  AtomicConstants.dat DABAX file because oxigen does not exist in
	  crystalline state. Therefore the averaged value seems not realistic.
	  This option allows to customize the Debye temperatures from 
	  default (note that values of Debye temperature found in bibliography 
	  change significatively from one reference to another) and also allows
	  to enter average values of atomic mass and Debye temperature by 
	  entering identical values foe all atomic sites. 
	  Note that if values are changed in this window, they are not
	  saved for further runs, nor saved to input files like
	  xcrystal.xop. 


CUTOFF: The value of the cutoff in Intensity (normalized to 100) for 
	displaying reflections. 

DABAX FILE FOR ATOM. SCAT.: 
	Select a DABAX file from where the f0 component of the structure 
	factor will be read.

DABAX FILE FOR ANOM. SCAT.: Select a DABAX file from where the f1f2 
        components of the structure factor will be read.

UNIT CELL FROM: 
	obtain information on unit cell from either the "Unit Cell"
        panel or from external file
FILE: If Unit Cell info comes from a file, enter here the file name.
        If ? is set, the application will start a file browser
        for selecting it. 



