peak
Manual
Introduction
Program PEAK is designed for evaluating the positions of peaks for scattering profiles and calculating the structural characteristics of the systems.
PEAK User Interface
Using PEAK
Data manipulations with PEAK
| Operation | Description |
|---|---|
| LOAD DATA | 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 from PEAK
Structural parameters that can be calulated from the characteristics of the peaks:
| Bragg spacing | d = 2\pi/ S~max~ |
| long-range order dimension | L =\lambda/ (etas * cos ( heta~Max~) ) |
| radius of interaction | R~m~= (\pi/2.5)^2^*\lambda/eta~s~ |
| degree of disorder | \Delta/d = (1/\pi) * (eta~s~* d /\lambda)^1/2^ |
where \lambda represents the wavelength of X-rays, eta ~s~ the full width at a half-maximum intensity of the peak (in radians) and heta ~max~ the scattering angle corresponding to Smax. The wavelength \lambda has default value 1.5 Angstroem, it is possible to set \lambda value if you run Peak from the command line with the argument: “peak.exe 3.0” - will use \lambda =3.0 Angstroem for Peak calculations.