Intermediate range order

The most direct information obtained from LEED is the periodicity and intermediate range order within the transfer width of the surface under investigation. This can be gathered by visual inspection of the diffraction pattern and/or by relatively simple mathematical transformations of the spot profiles. 

The intermediate-range order, beyond the short-range local order as characterized by the polyhedral units in covalent glasses, is of considerable interest. There is increasing evidence for the existence of fairly well-defined clusters of atoms, containing 10 or more atoms, in the structure of certain covalent glasses (e.g. Ge-Se alloys) vibrational spectroscopy as well as diffraction experiments indicate their presence. 

Sampath, S., Benmore, C.J., Lantzky, K.M., Neuefeind, J., et al. (2003) Intermediate-Range Order in Permanently Densified Ge02 Glass, Phys. Rev. Lett. 90(11), 115502. 

Thus, in all discussed oxides, the structural transformations under pressure can be described as a multiple set of transformations. First, changes occur in the intermediate-range order with a slight increase in the coordination number and a transition to the rigid network state then, a coordination transformation with the increase of the first coordination number follows. According to the computer simulation data, additional buildup of pressure to the megabar range causes a subsequent complementary increase in the coordination number. 

Intermediate range order, network voids and stress... 

Short range order (defects) Intermediate range order (band tails) Long range order (crystal)... 

The short- and intermediate-range order of the polyphosphate glass network of the composition xZnO + (1 — x)P205 is investigated, with 0.35 < x < 0.80. The short-range order is probed using P solid-state MAS NMR, liquid-state NMR and Raman spectroscopy. ... 

The most powerful tool to study the intermediate range order in amorphous Si/B/N/(C) networks is MAS-NMR spectroscopy including advanced double resonance techniques such as B- Si rotational echo double resonance (REDOR), Si- B] rotational echo adiabatic passage double resonance (REAPDOR), and C- B] REAPDOR. These methods utilize the heteronu-clear coupling between the observed nucleus and a nucleus in the second coordination sphere to get information about the internuclear distance of the two nuclei. 

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