# Ultrastable glass (Richard Stephens)

###### tags: `PhD projects` `glass`

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## TCC

I did the TCC analysis on the configurations that they provided. Underneath, I show for one of the configurations the number of clusters of a certain type each particle is involved in. The TCC clusters that are often found in fluids are colored with a blue gradient, whereas the clusters that are often found in crystalline structures are colored with a red gradient.

One can clearly see that the blue (fluid-like) clusters are all highly correlated and indeed form distinct regions. Richard also found these icosahedral regions (13A=icosahedron). Furthermore, we see that the red (crystalline-like) clusters mostly recide in the regions where there are less or no blue clusters. This is most obvious when comparing, e.g., 11E and 8A.

Note that, even though many of the blue clusters are made up of tetrahedral subclusters, the sp3b cluster (which is a tetrahedron) is more prominent in regions where there are typically less of the blue clusters. But I think that this is just the result of a flaw in the TCC algorithm. I noticed that flaw before and Emanuele also commented on it. So that is why generally ignored the results of the sp3a/b, sp4a/b, and sp5a/b clusters. I believe the TCC algorithm just "forgets" these basic clusters when it constructs the other more complex clusters from these basic clusters.

| **7A**          | **7K**          | **8B** | **9B** | **10B**          |
| ---- | ---- | ---- | ---- | ---- |
|  |  |  |  |  |
|  |  |  |  |  |
| **11E** | **13A** | **Pyr3** | **Pyr4** | **Pyr5** |
|  |  |  |  |  |
|  |  |  |  |  |
| **6A** | **8A** | **9K** | **11F** | **BCC9** |
|  |  |  |  |  |
|  |  |  |  |  |

If you need a refresher on what the specific TCC clusters actually look like, see the figure below. Additionally, Pyr3 is a tetrahedron, and Pyr4 is a square pyramid, and Pyr5 is a pentagonal pyramid. These are calculated with Frank's adaption of the TCC code.

## Tetrahedrality
We can look at the average tetrahedrality in the systems. For that I only take the particles into account with $10<z<25$, as Richard suggested in his email (to avoid surface and substrate effects). Underneath I show for each folder (i.e. 1spn206, 1spn216, 1spn2056) the average tetrahedrality in each file. The folders indicate different temperatures. The files in the folders are apparently labeled according to their swapping intensity but I do not know what the difference is between the labels, e.g., 01 or 01a.