O-hole

Figure 3.34. Holes in the closest packing of equal spheres. Two superimposed layers of spheres are shown (continuous and dotted lines). Tetrahedral (T) and octahedral (O) holes are indicated.

Fig. 2-lS. Donor and acceptor levels in silicon crystals = electron, O = hole. 

Filling of interstices S2 in half of the T-holes S2 in half of the T-holes F in every T-hole Na+ in every O-hole Ni3+ in every O-hole Ti4+ in half of the O-holes Ti4+ in half of the O-holes Al3+ in two-thirds of the O-holes... 

A closely related group of AB2O4 oxides has the inverse spinel structure. Here, again, there is a ccp array of 02, but the B atoms are equally divided between T- and O-sites, and all of the A ions appear in O-, not T-, holes. Thus, we have B(AB)C>4 with B in one-eighth of the T-holes, A in one-quarter of the O-holes, and B in one-quarter of the O-holes. 

Where the lithium ions fit best will be determined by their size relative to the iodide ions. Note from above that there are two types of interstices in a closest packed structure. These represent tetrahedral (f) and octahedral (o) holes because the coordination of a small ion fitted into them is either tetrahedral or octahedral (see Fig. 4.12). The octahedral holes are considerably larger than the tetrahedral holes and can accommodate larger cations without severe distortion of the structure. In lithium iodide the lithium ions fit into the octahedral holes in a cubic closest packed lattice of iodide ions. The resulting structure is the same as found in sodium chloride and is face-centered (note that face-centered cubic and cubic closest packed describe the same lattice). 

Figure 1 2 10. The reduced Lifshitz parameter"z" - (ET - EF)/(EA- ET), where (EA- Er) is the full energy band dispersion in the c-axis direction, as a function of the number of holes in the G subband in A1 doped MgB2. The quantum uncertainty in the z value is indicated by the error bars that are given by D (

P. Politzer et al., o-Hole bonding between like atoms a fallacy of atomic charges. J. Mol. Model. 14, 659-665 (2008)... 

When the hopping frequency of the a-hole is equal to the resonance frequency of the jr-bond there are two equally important normal modes of the total system o-hole and 7r-bond, one where the hole and screening charge oscillate together in phase between the... 

Figure 1 The schematic representation of various electronic excitation mechanisms due to ac or dc external electric fields (a) the tuneling electrons from the valence band (VB) to the conduction band (CB) and ionization of an acceptor state (-o-) (Zener effect) followed by electron-hole recombination, indicated by horizontal and vertical arrows, respectively (b) excitation or ionization by electron impact (c) recombination of electrons ( ) and (o) holes at a semiconductor p-n junction and (d) bulk recombination of electrons and holes injected from electrodes. Adapted from Ref. 2...

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