Table 2. Calculated 27Al Unscaled and Scaled Hyperfine Shifts for Al-Doped Goethite and Lepidocrocite Configurationsa.
| unscaled 27Al shifts/105 ppm |
scaled 27Al shifts/ppm |
|||
|---|---|---|---|---|
| configuration | Al atom 1 | Al atom 2 | Al atom 1 | Al atom 2 |
| goethite | ||||
| single | 4.88 | 1070 | ||
| 1NN | 2.93 | 2.93 | 643 | 643 |
| 2NN | 5.64 | 5.64 | 1240 | 1240 |
| 3NN | 4.10 | 4.29 | 900 | 942 |
| lepidocrocite | ||||
| single | 7.71 | 6960 | ||
| 1NN | 7.24 | 7.25 | 6530 | 6540 |
| 2NN | 7.52 | 7.59 | 6790 | 6840 |
| 3NN | 3.44 | 3.44 | 3110 | 3100 |
a
Atom 1 and 2 refer to values observed when two ions are substituted into the goethite/lepidocrocite lattice.