Orbital interaction high-spin

In addition to the electrostatic effect, there is the contribution to the chemical bond which is the result of the distribution of electrons over the metal d-atomic orbitals, the ligand field effect . The contribution of this effect is smallest when only five electrons are present and distributed over the five d-atomic orbitals. The each electron occupies one atomic orbital (the high-spin state) thus resulting in a spherical electron distribution. When the electron distribution is nonspherical, additional stabilizing interactions occur due to the redistribution of electrons over the d-atomic orbitals. This effect is a maximum for d-electron counts of three or eight. 

As seen in the radiationless process, intercombinational radiative transitions can also be affected by spin-orbit interaction. As stated previously, spin-orbit coupling serves to mix singlet and triplet states. Although this mixing is of a highly complex nature, some insight can be gained by first-order perturbation theory. From first-order perturbation theory one can write a total wave function for the triplet state as... 

High-field EPR (HFEPR) spectroscopy greatly improves the resolution of the EPR signals for spectral features such as the g-tensor. Deviations of the g-value from free electron g=2.0023 are due to spin-orbital interactions, which are one of the most important structural characteristics (Kevan and Bowman 1990). Using a higher frequency results in enhanced spectral resolution in accordance with the resonance equation ... 

Both the Slater and the rrkm treatments are inappropriate for calculations of °°, since the dissociation is not characterized by a critical extension of one bond, but rather by the transition from one potential surface to another. In such a case the observed activation energy at high pressures will be lower than the energy threshold for reaction110. From their high-pressure data Olschewski et a/.109 calculate that E0 = 63 kcaLmole-1 and that the transition matrix-element is 100 caLmole-1, which is in good agreement with the spin-orbit interaction term for O atoms. 

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