Table 3. Unit Cell Parameters for ZIF-8 and ZnZn-RPM Obtained via Energy Minimization (opt) and Averaging over the MD Trajectory (avg.) at SCC DFTB and GFN2-xTB Level in Comparison to the Experimental Reference Dataa.
| system | cell size | parameter set | kmax | a/Å | b/Å | c/Å |
|---|---|---|---|---|---|---|
| ZIF-8 | 1·1·1 | avg. 3ob | 2 | 17.073 | ||
| avg. 3ob | 1 | 17.049 | ||||
| avg. 3ob | 0 | 17.042 | ||||
| avg. GFN2 | 1 | 16.700 | ||||
| opt. 3ob | 2 | 16.991 | ||||
| opt. 3ob | 1 | 16.991 | ||||
| opt. 3ob | 0 | 16.991 | ||||
| opt. GFN2 | 1 | 16.672 | ||||
| exp. 298 K61 | 17.0095(8) | |||||
| ZnZn-RPM | 1·1·1 | avg. semi 3ob | 2 | 17.299 | 16.528 | 22.435 |
| avg. xy 3ob | 2 | 16.966 | 16.836 | 22.433 | ||
| avg. xy 3ob | 1 | 16.970 | 16.840 | 22.418 | ||
| avg. xy 3ob | 0 | 16.970 | 16.840 | 22.420 | ||
| avg. xy GFN2 | 1 | 16.457 | 16.574 | 21.895 | ||
| opt. 3ob | 2 | 16.909 | 16.927 | 22.462 | ||
| opt. 3ob | 1 | 16.911 | 16.931 | 22.465 | ||
| opt. 3ob | 0 | 16.911 | 16.931 | 22.465 | ||
| opt. GFN2 | 1 | 16.543 | 16.576 | 22.121 | ||
| exp. 100 K60 | 16.598(2) | 16.643(2) | 22.494(3) |
a
In case of ZnZn-RPM simulations semi- as well as xy-isotropic pressure coupling has been employed.