Search-Match Module

This module is used for phase identification by searching the structure repositories for matching phases.

Getting started

Step 1: Phases

Select the structure repositories used for phase matching. The search-match process can be slow. Only including relevant repositories speeds up the process significantly.

Step 2: Restrictions (optional)

Limit the search-match process to phases with specific chemical compositions. This can be helpful if the chemical composition of the sample is known. Limiting the search process to phases matching the known composition significantly improves the hit rate. By clicking on elements in the periodic table, the elements are cycled through the following modes:

Discard optional is a shortcut to set all optional elements to discarded.

Step 3: Controls

Phases are matched to the dataset by running a Rietveld refinement with restricted parameters and comparing the goodness of fit. Here some refinement parameters can be controlled. They mostly affect the speed of the process and the variability during phase matching.

Step 4: Running Search-Match

Select "Run -> Search-Match" from the menu (or click the "Eye" button in the menu bar) to start the process.

Step 5: Evaluating Results and Searching Residuals

The matched phases are listed with descending figure of merit. The best match is always listed at the top of the score list.

To evaluate the score list, proceed as follows:

  1. Selecting a phase in the score list displays its hkl line positions in the graph. Use this function to decide whether or not the phase is really present.
  2. If the phase is confirmed to be present, pin it by clicking the "arrow down" button at the bottom of the score list. This will temporarily add the phase to the refinement project.
  3. If more unassigned peaks are present, repeat the search-match process. Pinned phases will be included in the peak fitting, and search-match will focus on the residual peaks.
  4. Repeat this process until all peaks are assigned to a phase.
  5. Once all peaks are assigned, the pinned phases must be permanently added to the refinement project. Click "Project -> Add-Remove phase" to open the phase dialog. All pinned phases are pre-checked. Click "ok" to add them to the project.

The column "Source" in the list of pinned phases indicates if the phase was pinned as a result of a search-match run ("matched"), or if it was previously added to the refinement project ("project"). Note that phases of source "project" cannot be unpinned ("arrow-up" button). They must be removed from the refinement project.

The score list can be exported to CSV format using the button "Save the score list".