Hole/electron hopping

Yang, S.I., R.K. Lammi, J. Seth, J.A. Riggs, T. Aral, D. Kim, D.F. Bocian, D. Holten, and J.S. Lindsey (1998). Excited-state energy transfer and ground-state hole/electron hopping in p-phenylene-linked porphyrin dimers. J. Phys. Chem. B 102(47), 9426-9436. 

Figure C3.2.15. Schematic diagram showing (A) electron hopping between electron reservoirs via empty states of an intervening bridge, (B) tunnelling, and (C) hole hopping via filled states of an intervening bridge. From...

Much theoretical work went into trying to understand these results more completely. Newns constructed a simple ID model that incorporated the idea of electrons hopping in and out of the tt anti-bonding orbital of NO as the means by which hot electron-hole pairs could transfer energy to the NO molecule.26 Using reasonable assumption, he was able to quantitatively reproduce the experimentally-observed surface temperature and incidence energy dependence. 

Figure 9.10 Antiferromagnetic ordering of magnetic moments on Cu2+ ions (a) the idealized structure of La2Cu04 showing magnetic moments on Cu2+ (b) the ordering in one Cu02 sheet and (c) introduction of holes (Cu3+) and electron hopping destroys the antiferromagnetic array.

Keywords Electron transfer Hole transport Hopping Superexchange Couphng to the molecular surroundings... 

For one hole in the half-filled band, the exact energy spectrum of the chain with free ends formed by L unit cells is spin-degenerate, similar to the spectrum of the uniform Hubbard chain with U = oo. In the case of periodic boundary conditions an electron hopping between the first and the last unit cells of the chain leads to the additional term to the Hamiltonian (9). For one hole in the half-filled band this term has the following form ... 

Electron transport through DNA, in which electron hopping involves radical anions of base pairs, is less likely to occur than hole hopping, involving radical cations, because the DNA bases have weak electron affinities 166 consequently, the energies of the anionic states of base pairs, in general, he well above those of conventional donor and acceptor chromophores. 

Fig. 17. According to some models discussed in text, PET in intramolecular rigid systems takes place by an electron hopping from the donor orbital along the LUMO of the spacer molecule or by hole hopping from the acceptor orbital along the HOMO or the spacer. These pathways are modulated by the energy gap between the orbitals of the spacer and those of the donor and acceptor...

The holes injected by ITO into PPV are blocked by the PMMA layer before reaching the Ca electrode. PMMA is a wide-bandgap insulator, so electron transport requires dispersion of electron-accepting molecules into it, between which electron hopping occurs. 

Creation of positive hole as electron hops from Ni to Ni + as more Li incorporated, more Ni sites created, and conductivity increases. 

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