by Pasquale Pavone for exciting carbon

Purpose: In this tutorial, the NOMAD Repository will be introduced. Furthermore, it will be explained how to use it for searching and downloading results of ab-initio calculations.

1. What is NOMAD?

The Novel Materials Discovery (NOMAD) Project is a European Centre of Excellence which is aimed to developing tools for material science and engineering.

In particular, the NOMAD Laboratory develops a Materials Encyclopedia, Big-Data Analytics, and Advanced Graphics Tools.

Eight complementary computational materials science groups and four high-performance computing centers form the synergetic core of this Centre of Excellence participate in the development of the NOMAD Project.

i) The NOMAD Repository

The NOMAD Repository is the part of the NOMAD Project which was established to host, organize, and share materials data. By following the link to the repository webpage, you see the following on the screen.

In particular, you can notice in the right panel some news indicating the actual number of calculations which are contained in the repository.

2. How to use the NOMAD Repository for searching and downloading results of calculations

In order to proceed with the search, proceed to the NOMAD Repository webpage and click on the Search and download button in the horizontal black command bar.

A new page will appear with the search queries.

i) Your very first search example

As a first example of search we will look for all calculations in the repository which are performed on systems containig both the boron and nitrogen atoms and which are using the (L)APW+lo method, a quite specific search. In order to do that, start your query by clicking the boron element (B) in the periodic table in the section Chemical Elements.

Wait a few seconds which are used by the searching machine of the repository for sorting your query. Then, using the same procedure, add the nitrogen element (N).

Notice that after each choice, the field of remaining elements will be restricted to the ones for which calculations are present in the repository, compatibly with the choices you have already done.

Now, click on the lens symbol in Basis set type of the Methodology section and choose the (L)APW+lo method.

You may notice that all your current queries appear in the left top part of the screen.

Here, if you wish, you can delete one or more topics from the query list. If you want now to procede with the search, push the Search button on the top left margin of the screen.

After a few seconds the results of your search will appear on the screen.

Due to the very selective queries, only two calculations appear on the screen. We choose to concentrate on the second item found and we click on the corresponding Show button. A new small window will appear.

Then we can try to download some results of this calculation. In order to let them appear, click on the numerical identifier in the small window.
Now, you shoud get the following.

Among the indicated files you can select those you want to download by first clicking on the corresponding small icons.

Finally, for the download click on the Download selected files button. The selected files will be now in your computer.