Table 8. IQA Two-Center Terms for Relevant Interactions in Hexagonal Graphite, BN, and MgB2a.
| A–B | m | RAB | δAB | EnnAB | EneAB | EneBA | ECoulAB | EclAB | ExAB |
|---|---|---|---|---|---|---|---|---|---|
| C–C(1)ab | 3 | 1.423 | 1.202 | 13.391 | –13.098 | –13.102 | 12.846 | 0.037 | –0.372 |
| C–C(2)ab | 6 | 2.464 | 0.054 | 7.731 | –7.692 | –7.692 | 7.655 | 0.002 | –0.007 |
| C–C(3)ab | 3 | 2.845 | 0.037 | 6.696 | –6.679 | –6.681 | 6.665 | 0.001 | –0.004 |
| C–C(4)c | 1 | 3.356 | 0.019 | 5.677 | –5.709 | –5.709 | 5.746 | 0.004 | –0.003 |
| C–C(5)c | 6 + 3 | 3.645 | 0.006 | 5.227 | –5.245 | –5.247 | 5.266 | 0.001 | –0.001 |
| B–N(1)ab | 3 | 1.446 | 0.452 | 12.810 | –16.751 | –7.065 | 9.244 | –1.762 | –0.135 |
| B–B(2)ab | 3 | 2.504 | 0.004 | 5.283 | –2.936 | –2.935 | 1.632 | 1.043 | –0.000 |
| N–N(2)ab | 3 | 2.504 | 0.212 | 10.354 | –13.604 | –13.605 | 17.877 | 1.021 | –0.040 |
| B–N(3)ab | 3 | 2.892 | 0.008 | 6.405 | –8.419 | –3.564 | 4.685 | –0.893 | –0.001 |
| B–N(4)c | 2 | 3.329 | 0.006 | 5.563 | –7.329 | –3.110 | 4.101 | –0.776 | –0.001 |
| N–N(5)c | 3 | 3.630 | 0.024 | 7.144 | –9.411 | –9.410 | 12.403 | 0.726 | –0.003 |
| B–B(1)ab | 3 | 1.781 | 0.983 | 7.429 | –8.392 | –8.392 | 9.522 | 0.166 | –0.249 |
| B–B(3)ab | 6 | 3.085 | 0.052 | 4.289 | –4.953 | –4.953 | 5.722 | 0.106 | –0.006 |
| B–B(5)ab | 3 | 3.562 | 0.017 | 3.714 | –4.303 | –4.303 | 4.987 | 0.095 | –0.002 |
| Mg–B(2)c | 12 | 2.504 | 0.061 | 12.681 | –14.830 | –10.964 | 12.824 | –0.290 | –0.013 |
| Mg–Mg(3)ab | 3 | 3.085 | 0.003 | 24.704 | –21.364 | –21.364 | 18.475 | 0.450 | –0.000 |
a
The reference units corresponding
to 
are G = C1C2, G = B1N1, and G = MgB1B2. Energies in Ha;
distances in Å units. Key: ab, intralayer interaction; c, interlayer interaction