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Search String Syntax
The case-sensitive elements may be followed by a number, a bracketed range of numbers,
or an asterisk (to allow any number of that element).
If an element is not followed by anything, it is considered a bare element and is treated
as in the following example:
- Formula field: 'Sn' will be interpreted as 'Sn1'
- Optional field: 'Sn' will be interpreted as 'Sn*'
- Exclude field: 'Sn' will be interpreted as 'Sn*'
Bracketed Range [n-m]
Use the square bracket syntax to designate a range of an element's qualifiers, from minimum
to maximum, inclusive, e.g., "C[2-3]". In this example, the search will return all
molecules that have either two carbon (C2) or three carbon (C3) atoms. Another range
example might be "C[2-4]H[3-5]O2". In this example, the search will return all molecules
that have [C2, C3, or C4], and [H3, H4, or H5], and O2 in their atomic formula.
Asterisk
Use an asterisk as a wildcard to specify any number of a certain element,
e.g. "C2H4O*" will return all molecules with 2 carbon atoms, 4 hydrogen atoms,
and at least one oxygen atom (C2H4O1, C2H4O2, C2H4O3, etc.).
Optional Elements
Entering elements in the Optional Elements text field allows the user to target
searches for a specific subset of elements. For example, Formula: Si*O*, Optional:
H*Cl* retrieves all molecules containing at least one Si atom and one O atom, plus
any combination (including none) of the elements H and Cl.
Excluded Elements
The use of the Excluded Elements text field is helpful when checking the box
"Allow elements not specified in formula"
retrieves too many molecules.
Example: Formula:
Si1, "Allow elements..." box checked, Exclude: C*B*. This retrieves all
compounds containing at least one Si atom, plus any other elements except
carbon or boron.
Allow Additional Elements
Use the checkbox to include unspecified elements, e.g. entering
"C2H4" and
checking the checkbox will return everything with 2 carbon atoms and
4 hydrogen atoms (C2H4O1, C2H4Si1, C2H4O2, C2H4N1O2, etc.).
The "Allow elements..." checkbox can be used in combination with *
to perform broader searches.
For example, entering "Al*" in the Formula field and checking the
"Allow elements not specified in formula."
box, will return all molecules that have at least one aluminum atom.
The checkbox will be ignored if there is an entry in the Optional Elements field.
Element Uniqueness
Elements should appear in the Formula field only once, and parentheses should not be used.
For example, (CH3)2CHCH3 should be written as C4H10.
The unique element rule only applies to the Formula field, i.e., the user can enter
the same element two or more times in either the Optional Elements or
Exclude Elements fields.
More Complex Searches
Using multiple searches while saving intermediate results in the Cart
allows the user to emulate complex searches.
In the Cart, use the Delete button to weed out unwanted molecules,
e.g., to remove electronic excited states of a molecule or isomers
that are less stable (i.e., have higher heats of formation) than
the ground-state configuration.
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![[ORNL]](http://public.ca.sandia.gov/HiTempThermo/images/ornl_small.jpg){kind=small}
