Program PEAK is designed for evaluating the positions of peaks for
scattering profiles and calculating the structural characteristics
of the systems.
PEAK is compiled using Intel Fortran v.11.0 with QuickWin graphics library and
runs under MS Windows 95/98/NT/2000/XP/Vista or under Windows emulators
(like WINE) installed on Linux/MAC.
If you use results from PEAK in your own publication, please cite:
Choose "FILE" menu option and then "LOAD" submenu. The loading file
must contain two column: the first column - X axis, the second
column - Y axis.
SCALE AND ZOOM
Click menu option "OPTIONS". One can choose to plot the graph on
logarithmic "LOG SCALE" or absolute scale "ABS SCALE" as well as make
zooming for the interested part of the graph. For this it is necessary
to click "ZOOM" submenu, then double click on the left mouse button
for choosing left upper window corner of zooming region, after that
click right mouse button for choosing the right bottom corner of the
zooming window.
SELECT FITTING REGION
Choose "SELECT" menu option. Click on the left mouse button for selecting
fitting region, for the last point (to finish selecting process) click
right mouse button. The fit at the selected regions will be drawn with
green color. The values of spacing and width for each peak will be shown
on the graph.
SAVE OPTION
One can save the fitting information through "PARAMETERS" menu option.
Choose "SAVE FIT" for saving experimental data and corresponding fits.
(format: column 1-2 original data (X,Y axes), 3-4 the first fit, 5-6 the
second fit etc.). File has the extention 'fit'. Choose "SAVE PAR" submenu
for storing the information about structural parameters for each fitted
peak. File has the extention 'out'. For seeing structural parameters on
the screen choose "SHOW PAR" submenu.
RESET
Choose 'RESET' menu option for beginning with the new attempt of
the fitting. The experimental curve will be redrawn without previous
information of fitted peaks.
Structural parameters that can be calulated from the characteristics of
the peaks:
Bragg spacing
d = 2π / Smax
long-range order dimension
L = λ / ( βs * cos (θMax) )
radius of interaction
Rm = (π/2.5)2 * λ / βs
degree of disorder
Δ/d = (1/π) * ( βs * d / λ ) 1/2
where λ represents the wavelength of X-rays, βs the full width
at a half-maximum intensity of the peak (in radians) and θmax the
scattering angle corresponding to Smax.
The wavelength λ has default value 1.5 Angstroem, it is possible to set
λ value if you run Peak from the command line with the argument:
"peak.exe 3.0" - will use λ=3.0 Angstroem for Peak calculations.
