Configuration relative energies

On the right side of Fig. 3-9 are represented the relative energies of the two Tig terms, the and 2g. The ground term is the from the 2g configuration. Spin-allowed electronic transitions (those between terms of the same spin angular momentum - but see also Sections 3.6, 3.7 and Chapter 4) now take place upon excitation from -> A2g, The d-d spectra of octahedrally... 

FIGURE 5.16 Crystal-field pictures for the low-spin d5 system in deformed octahedra. (a) relative energy of d-orbitals for an octahedron with strong crystal field (b) d-orbitals of the T2s set in a rhombically distorted octahedron (c) three possible electron configurations of increasing total energy (d) the term scheme for the configurations in (c). 

Table III summarizes the reported relative energies appropriate to the BC, Si—AB, and B—AB sites for the H—B pair in silicon. In many calculations, the B—AB site has been predicted from calculations to be not only higher in energy than the BC site but also to be a saddle point for reorientation between equivalent BC sites. Some calculations predict that the Si—AB site may be metastable, consistent with evidence from channeling and PAC studies. The computed total-energy differences, however, between the stable (BC) and metastable (Si—AB) configurations might be too large to explain the simultaneous observation of both species at the reported temperatures.

Step 1. Rank the basis set configurations according to their relative energy. This can be implemented by means of Eqs. (29) to (33). 

In some cases, the relative energy orderings of the A B" and A B configurations of the 1,1 isomer depends on the type of computation. However, the A A configuration of the 1,2 isomer lies always between the A B" and A"B configurations of the 1,1 isomer. 

Various hybridization states of the phosphorus atom have been parameterized in various force fields (Table 9). If a force field is to be useful for pentacoordinated phosphoranes, the relative energies of the two basic configurations, trigonal bypyramid (62) and square pyramid (63), must be differentiated. For this purpose, a 1,3-non-bonded interaction term centered only at the central phosphorus atom was added to MMI. In this modification, account was ts en of... 

A relative ratio between the 4/ and 4/ 5d-configuration levels energies specifies a sharply distinctive position of broad bands in the spectra of trivalent and divalent rare-earth ions, hi the TR + spectra, with the exception of Ce +, broad bands fall into a relatively far UV region and they yield only fine spectra in the visible and adjacent regions. In the spectra broad bands fall into the visible and near-UV regions. Thus in the case of TR + the f-d and /-/ transitions he close to each other and overlap. Three individual cases are distinguished in the TR + liuninescence spectra, namely broad bands due to d-f transitions, line IR spectra and a combination of bands and fines. 

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