International XAFS DB Portal

IXDB Statistics

The following tables show real-time statistical data obtained from the MatVoc vocabulary endpoint and NIMS knowledge base endpoint. (Detailed access information is provided at the bottom of the page.)

Linked XAFS spectra

IXDB is linked to databases around the world. This table shows the number of links to each database.

Absorption edges

The number of unique absorption edges that can be found in IXDB, and the lightest and heaviest elements of each absorption edge. Not all elements between these are included. For example, inert gases such as Ar are not included.

Materials

This is the number of materials that can be searched in IXDB. The boundary between organic and bio materials is not clear, but biomaterials are distinguished as organic chemicals with higher structures that exhibit biological functions. This indicates the breadth of the cross-search field, but has no special meaning in XAFS analyses.
As shown in this table, not all materials have chemical formulas. Alloys and composites without chemical formulas are also included in the IXDB.

XAFS Simulation Data

IXDB primarily handles experimental data, but it is also linked to simulation data. The reason why there are fewer "Unique links" than "Materials" is that different materials, such as isomers, may have the same link.

HAXPES Spectra

HAXPES is a spectroscopic analysis method that uses physical processes similar to those of XAFS. IXDB provides links to external HAXPES databases. Here, "Work" refers to a unit of data in the MDR XAFS DB, which is roughly equivalent to a "folder" containing spectra measured for a given sample. Each Work is assigned a DOI, which serves as the link destination.

Crystallographic Data

Crystallography data provides long-range order information than local structure analysis using XAFS. These data will provide initial structures for recursive XAFS analysis and hints for possible structures. The Crystallography Open Database includes geometric information under special conditions, such as crystal structures under high pressure. The selection is left to the user.

Phase Diagrams

The phase diagrams provided here systematically show the stability of structures and the possibilities of other structures. Since multiple states are included in a single diagram, the number of diagrams is less than the number of materials. By sending semantic queries to the above endpoints, it is also possible to obtain XAFS spectra of different materials in the same diagram.

Properties

The final macroscopic structure exhibits various physical properties. Here, we provide related information from a macroscopic perspective extended from the local structure of XAFS. This information includes crystal structures and electronic states, which will be useful for materials exploration. Basically, the information is linked by the chemical formula of the main material, so isomers and hydrates may be found in the same link.

The statistical data is obtained from the following SPARQL endpoints.
Vocabulary: https://matvoc.nims.go.jp/graph/sparql
Knowledge base: https://materials-open-rdf.nims.go.jp/sparql
Graph Identifier: https://ixdb-rdf_7.nims.go.jp/