Searching the luminescence database

About the CSIRO Luminescence Database

The CSIRO Luminescence Database is a free-to-use reference tool for researchers in the fields of cathodoluminescence, photoluminescence, ionoluminescence, and related luminescence spectroscopies. The database lists emission lines from a range of materials, including minerals and synthetic compounds. At present, the database contains approximately 3200 entries of known luminescence emission lines, which were compiled from published literature on luminescence spectroscopy. Please see the acknowledgements page for the list of contributors.

On-line access

The CSIRO Luminescence Database is searchable on the web via http://www.csiro.au/luminescence/.

Off-line access

An off-line version of the CSIRO Luminescence Database is included with OpticalFit, the use of which shall be explained below:

Opening luminescence database

To open the luminescence database window, select the 'Database→Luminescence database' option in the OpticalFit menu, as below:

This will open the 'Luminescence Database' search window, shown below:

The 'luminescence database' window allows users to quickly search for emission lines based on three search criteria; material name, chemical formula or emission centre. Lines and bands that match the current search settings are overlaid on the spectrum plot, as shown below, and reference spectra may also be plotted.

Compact and Expanded views

The default display mode for the 'Luminescence database' is the 'compact' view, shown below. This window allows the user to perform a primary search by material name, material formula, or by emitter name. A secondary search is available by emitter or by material name, depending on the primary search mode. In the example below, the primary search is by material, and the secondary search is by emitter.

If the user clicks on the 'More »' button, the 'Luminescence database' will convert to the 'expanded' view, shown below (the '« Less' button converts back to the 'compact' view). The 'Expanded' view has the same primary and secondary search controls as the 'compact' view, but also includes a results table that lists the database entries for the current search results, and permits a greater degree of control over which lines and reference spectra are plotted in the OpticalFit display.

The results list in the 'expanded' view is interactive, and allows the user to perform actions that are not possible through the 'compact' view, including:

• Users may select to display only some of the lines in the search results in the spectrum plot, using the Windows standard CTRL+left click / SHIFT+left click selection method.
• Users may select to display some or all of the reference spectra associated only some of the lines in the search results in the spectrum plot.
• Users may view the full database entry for each line, and edit user-generated database entries.
• Users may add particular database lines to the current peak fitting table (see adding database lines to the peak table section.)

Database search criteria

Primary search

Users may search the database for luminescence lines using three search criteria; material name, chemical formula, or emitter name. The search criterion is selected using a drop-down list, as shown below:

Depending on your choice of search criterion, the primary search list in the 'Luminescence database' window will be populated with all the materials, formulas or emitters in the database. The example below shows the primary search list when searching by material name.

Typing in the search field

To select a material/formula/emitter, either scroll through the drop-down list and click on the desired list item, or type the name in the edit field above the drop-down list. It is not necessary to type the complete name; if you pause after typing a few characters, the Luminescence Database window will automatically search the database for values matching your input. If only one material/formula/emitter matches your input, it will be automatically selected. If there are multiple matches, the drop-down list will be opened, scrolled to the first item matching your input (note: search is case insensitive). For example, if you type “adu” and then pause, the database automatically select “adularia”, as that is the only material that matches “adu”. However, if you type only “ad”, the database will find two matches (“adamite” and “adularia”), so the drop-down list will open starting at “adamite”, allowing you to select the desired material.

Secondary search

In addition to the primary search field, the luminescence database window has a secondary search field that allows the user to optionally refine the search results. The search criterion for the secondary search is automatically set to 'emitter' when the primary search criterion is 'material' or 'formula', and is set to 'material' when the primary search criterion is 'emitter'. If the user wishes to show all results that match the primary search criterion, then they may select the 'All emitters' / 'All materials' item in the secondary search (this is the default selection.)

Users may note that if they want to select several, but not all, items in the secondary search menu, they can do this using the selection tools in the expanded view of the 'Luminescence database' window.

Search by material

The most commonly used search method in the luminescence database is to search by material name, as users often know the identity of the material being analysed, but not necessarily which trace dopant or defects are present that give rise to luminescence. At present, there are 456 materials in the database, which may be selected from the material drop-down list, or typed in the search field.

If the user needs to further refine the search results, the secondary search drop list may be used to filter the results by the emitter.

Note that when selecting by material name, the results list may contain several variants of the material that have the same structure but may vary in trace dopants, defects or crystallite sizes. The material variant (if given) is displayed in the 'material' column of the results table in the 'expanded' view, as shown below.

Search by formula

When the primary search mode is 'formula', the first dropdown list contains a list of all the chemical formulas given for emission lines in the database (as shown below). This search mode may be useful when the user knows the composition / nominal formula of the material, but is not certain of the structural polymorph. For example, searching by a formula of 'Al2O3' returns luminescence results from ruby, sapphire, corundum, and synthetic alumina (bulk and nanopowders).

When the primary search mode is 'formula', the secondary search mode is 'emitter', which allows the user to refine the search results if necessary.

Note that when selecting by formula, the results list may contain several polymorphs that have the same formula but different structure, which can also affect the luminescence emission. The material/polymorph name (and variant, if given) is displayed in the 'material' column of the results table in the 'expanded' view, as shown below. In the example below, the CaCO₃ formula matches two materials (calcite and aragonite), and that for calcite there are several variants noted (e.g. 'st1e', 'Terlingua', and 'Iceland spar'.)

Search by emitter

Searching by emitter may be useful for identifying peaks from some emitters that have consistent emission bands across a variety of host materials, such as Dy and (to a lesser degree) Fe:

When the primary search mode is 'emitter', the search drop-down list is filled with all the emitter values from the database, including elements, ionic groups, defects, vacancies, and the like, as shown below:

When the primary search mode is 'emitter', the secondary search mode is 'material', which allows the user to refine the search results if necessary.

However, it should be noted that luminescence lines do not have constant energy or band structure regardless of host matrix, as is (mostly) the case in x-ray spectrometry, for example. With optical luminescence, some emitters will produce sharp lines at consistent energies across a number of matrices (e.g. rare earths like Dy³⁺ or Gd³⁺), whilst others produce lines that change in energy depending on the host matrix (e.g. Ti, TiO₆^8-, Ce³⁺, Pb, oxygen, etc.) The examples below show the matrix-dependent energy of luminescence from Yb and VO₄, indicating that luminescence of these emitters in one matrix is by no means a characteristic fingerprint for the luminescence of these emitters in another matrix.

Finally, the 'emitter' list also contains emitters that have little to no correlation between different materials, such as 'intrinsic', 'oxygen vacancy', etc. For these emitters, plotting the correlation of line positions is meaningless.

Search results in the 'Extended' view

Line selection

For materials with many search results, it may be useful at times to select only specific line references from the database to be shown in the OpticalFit spectrum plot, with all other unselected lines hidden. To select a line, simply left-click the mouse on a line in the Luminescence Database window. You may select multiple lines by holding down the CTRL key when making a selection. In the example below, three reference lines for quartz have been selected in the Luminescence Database window, and only these lines are drawn in the OpticalFit spectrum plot (shown further below). To clear the selection and show all lines in the current search results, press the 'Select all' button in the top-right corner of the Luminescence database window.

Line highlighting

When the Luminescence Database search returns many results, it may be difficult to determine where a particular line reference in the Luminescence Database window is plotted in the OpticalFit spectrum plot. To locate lines in the spectrum plot, hover the mouse over the line entry in the luminescence database window, and the line will be highlighted in both the luminescence database window (below) and in the OpticalFit spectrum plot window (further below), using the same highlight colour. Likewise, hovering the mouse over a line set in the OpticalFit window will highlight the corresponding line entries in the Luminescence database window.

Spectral units

The emission peak positions are listed in the x-axis units selected in OpticalFit, which are eV by default. To change the line position to be displayed in nm or cm^-1, use the 'x-axis' menu options in OpticalFit (see changing x-axis units). The example below shows the search results for Mn in Calcite, plotted as eV (top) and nm (bottom).

Sorting columns

The search results in the 'extended' view of the luminescence database window can be sorted and re-ordered by left-clicking on the column headers of the results list. In the examples below, the results are sorted alphabetically by emitter (below left) and reverse-alphabetically (below right), as denoted by the 'Emitter [fwd]' and 'Emitter [rev]' column headers (for forward/reverse sorting, respectively).

Results can be sorted by any column by clicking on the relevant column header, though this is most often useful when sorting by line position, as shown below.

Viewing line information

You may view all the database information for a particular line entry by right-clicking on the entry in the results table, then selecting the 'View record' item in the popup context menu, as shown below.

Selecting the 'View record' context menu item will open the 'Edit line' window, as shown below. This window shows all the original data that was entered into the database for this line, some of which may or may not be displayed in the results list (e.g. temperature, relative height, etc.) Note that the edit controls are disabled in the window shown below; editing database values are allowed or user-created database entries, but are disabled for entries in the OEM database.

Adding database line entries to the peak table

When performing peak fitting in OpticalFit, users may directly import lines from the luminescence database into their peak table. To do this, right-click on the line entry in the 'expanded' view of the luminescence database window, then select the 'Add to peak fit table' menu item, as shown below.

This option will create a new entry in the peak table (shown below) using the position of the line entry in the database, as well as the FWHM if specified. The peak height is automatically fit to the spectrum, as is the FWHM if it is not specified in the database entry. Finally, the peak name in the table is automatically set to '[emitter] in [material], [reference]', using the information from the database entry.

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