Tools
The sub-menu
Tools
is shown on the left.
It includes graphical (Plot Options, Info, Presentation)
and computational (Find
P.O. and Le
Bail) options.
Press "Parameters" to supply your starting value or "Continue" to go on
is displayed at the bottom of the window.
The
Plot Options allow
to select the
datasets to plot on the screen by means of the General and Phases folders.
General folder includes: observed and calculated patterns, background line and Background Points, difference profile, X axis, reflections marks, Single or Reference range marks (see Fig. 3.1.1). The X scale can be choosen between "Two-Theta" and "d" values.
Fig. 3.1.1
Phases folder (see Fig. 3.1.2): for the selected phases it allows to choose between the calculated profile (available not before the Rietveld Procedure) and the relative Intensity (plotted as a vertical bar) of each reflection. Examples of the two kind of plot are shown in Fig. 3.1.3 and 3.1.4.
Fig. 3.1.2
Fig. 3.1.3
Fig. 3.1.4
The Info
sub-menu (on the left) allows to have
information about:
· the
reflections
(HKL)
· the Full Width at Half Maximum (FWHM)
· the Mixing
Parameters (Mixing Par.)
The
window shown in Fig. 3.2.1 is open. Clicking on any position by using the left mouse
button,the following information will be displayed:
"Two Theta", "d" and "counts" values
corresponding to the clicked point, on the Top; on the Bottom, Miller indices, 2-theta value and corresponding
phase of each reflection included into an interval 1.0 degree wide and centred on the clicked
point.
Fig.
3.2.1
Click on ">>" and "<<" buttons to scroll the list; click on Cancel to leave the sub-menu.
For a selected phase the Full Width at Half Maximum trend versus 2-theta is plotted (Fig. 3.2.2)
Fig. 3.2.2
When the Pearson VII or the Pseudo-Voigt
functions have been adopted to describe the profile shape of peaks, for a
selected phase the Mixing Parameter trend versus 2-theta is
plotted (Fig. 3.2.3);
Fig.
3.2.2
The Presentation sub-menu (on the left) allows to define:
The Find
P.O. option allows to run an
automatic procedure aiming at processing the selected phase in order to find possible directions of preferred orientation
(for
cylindrical symmetry samples). The candidate planes will
be displayed on the screen ordered as the increasing value of the corresponding
preferred orientation G parameter of the March-Dollase function
(see
Fig. 3.3.1 ). The user can eventually supply this information to the program by
means of the Parameters dialog-box.
Fig.
3.3.1
Fig.
3.4.1
The option is available at different stages of the run:
1) when the message
Press "Parameters" to supply your starting value or "Continue" to go onis displayed at the bottom of the window; at this stage the algorithm will be applied in the single peak refinement of the Preliminary procedure and in the subsequent Rietveld refinement, after each l.s.q. cycle;
2) when the message
Press "Refinement" to set your own strategy or "Continue" to go onis displayed at the bottom of the window and the initial calculated pattern is plotted; at this stage the algorithm will be applied in the subsequent Rietveld refinement, after each l.s.q. cycle;
3) when the message
Press "Refinement" to set your own strategy or "Exit" to stopis displayed at the bottom of the window and the final pattern is plotted; at this stage, after selecting the option, click on Continue button of the Main Menu to apply the Le Bail calculation and to plot the updated pattern; the algorithm will keep active in all the subsequent operations.