Racah parameters
The Israeli-Italian mathematician and physicist Giulio Racah observed that the electrostatic repulsion occurring in multi-electron systems can be described in its entirety by only three linear combinations of Slater's electron interaction integrals F k (Coulomb integral, exchange integral, repulsion integral). The abbreviations A , B and C for these linear combinations are called Racah parameters .
definition
- A = F 0 - 49F 4
- B = F 2 - 5F 4
- C = 35F 4
application
In complex chemistry , these are often used to describe the electrostatic repulsion of an electron configuration.
Tanabe-Sugano diagram for the d 2 configuration in the octahedral field
The following energy values apply:
| term | Parameterized energy values |
|---|---|
| 1 p | A + 14 B + 7 C |
| 1 D | A - 3 B + 2 C |
| 1 G | A + 4 B + 2 C |
| 3 P | A + 7 B |
| 3 F | A - 8 B |
From this, a power difference between P and Q terms of (carried A + 7 B (-) A - 8 B ) = 15 B .
Source
- Giulio Racah: Theory of Complex Spectra II . In: Physical Review . 62, 1942, p. 438. doi : 10.1103 / PhysRev.62.438 .
- Housecroft CE and Sharpe AG, Inorganic Chemistry , 2nd Updated Edition, Pearson Study, 2006.