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Tutorial
13
Fig. 14: The value ”P 1 21/c 1” for the database field ”space group” has been marked in the list
selection box.
The basic aim of a ”list selection box” is to provide the user with a quick and intuitive input
facility for restrainting values. Besides this, a list selection box is generally the most appropriate
way of entering the criteria, since the text strings of the database entries generally have to match
exactly the one entered by the user in order to be accepted, the only exception being the text
fragment searching (p. 10).
In order to select one or more values in the list selection box, simply mark the corresponding
line(s) and close the list selection box afterwards by clicking ”OK”. The corresponding ”values”
will be copied to the input field automatically. If you would like to mark more than a single
value/line, please click on the first line/value of interest, press the Shift key on your keyboard and
keep it pressed until you have clicked on the final value/line. All values/lines in between the two
lines will be marked as well.
You can easily jump to a certain line in the list by entering the first few characters (e.g. ”gre”
for ”green”) on your keyboard. M ATCH ! will automatically jump to the first line which starts
with the characters you have entered. If you do not enter a character for longer than 1.5 seconds,
this will reset the input buffer, so that you can start again with the first character.
Now you have to define the second new restraint, the density range. Please switch to the ”Properties”
page and have a look at the upper part of the dialog where the density values can be entered: There
are three lines for density values; in each line you can define a density range (min./max.). You can
search for calculated density values, measured values or any of them. Generally, it is recommended
to use the third option, in which case entries having either a calculated or measured density within
the defined range are accepted. In our case, the range for valid densities is 2.5-2.6 g/cm3 , so please
enter the numbers in the corresponding fields (Fig. 15).
Now the two additional restraints you could extract from your notes have been entered; please press
the ”Retrieve” button at the bottom of the Restraints dialog to start the actual database retrieval.
When the application of your new restraints to the reference database has been finished, you will be
informed about the result similar to your first retrieval.
However, something is different compared to the previous retrieval: This time, the restraints buffer
(and the answer set) already contain entries (the ones resulting from the first database retrieval).
Hence, you now cannot only load the resulting entries into the Results list or use them for future
search-match operations, but can also apply the newly found entries as restraints to the ones resulting
from the first restrainting operation (composition and journal name).
In order to do so, please select the ”Apply as restraints to current entries in Results list” option (Fig.
16)8 . Afterwards, please press ”Accept” to close the dialog. A single entry will remain in the Results
list; it is the only entry in the reference pattern database which matches all four criteria (composition,
journal, space group and density).
8 If you select the ”Show dialog as Advanced” option at the bottom of the dialog, it will be enlarged and display more
options. In the ”Advanced” mode, you can e.g. perform additional logical operations like OR.