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Fix CS1 deprecated date parameter errors

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'''Paracrystalline''' materials are defined as having short and medium range ordering in their lattice (similar to the [[liquid crystal]] phases) but lacking long-range ordering at least in one direction.<ref>{{cite journal|doi=10.1063/1.1407319|title=Structure and physical properties of paracrystalline atomistic models of amorphous silicon|year=2001|last1=Voyles|first1=P. M.|last2=Zotov|first2=N.|last3=Nakhmanson|first3=S. M.|last4=Drabold|first4=D. A.|last5=Gibson|first5=J. M.|last6=Treacy|first6=M. M. J.|last7=Keblinski|first7=P.|journal=Journal of Applied Physics|volume=90|issue=9|pages=4437|bibcode = 2001JAP....90.4437V }}</ref>

Ordering is the regularity in which atoms appear in a predictable lattice, as measured from one point. In a highly ordered, perfectly [[Crystalline solid|crystalline]] material, or [[single crystal]], the location of every atom in the structure can be described exactly measuring out from a single origin. Conversely, in a disordered structure such as a liquid or [[amorphous solid]], the location of the first and perhaps second nearest neighbors can be described from an origin (with some degree of uncertainty) and the ability to predict locations decreases rapidly from there out. The distance at which atom locations can be predicted is referred to as the [[correlation]] length <math>\xi</math>. A paracrystalline material exhibits correlation somewhere between the fully amorphous and fully crystalline.

The primary, most accessible source of [[crystallinity]] information is [[X-ray scattering techniques|X-ray diffraction]] and [[cryo-electron microscopy]],<ref>{{cite journal|last=Berriman|first=J. A.|coauthors=Li, S., Hewlett, L. J., Wasilewski, S., Kiskin, F. N., Carter, T., Hannah, M. J., Rosenthal, P. B.|title=Structural organization of Weibel-Palade bodies revealed by cryo-EM of vitrified endothelial cells|journal=Proceedings of the National Academy of Sciences|date=29 September 2009|volume=106|issue=41|pages=17407–17412|doi=10.1073/pnas.0902977106|bibcode = 2009PNAS..10617407B }}</ref> although other techniques may be needed to observe the complex structure of paracrystalline materials, such as [[fluctuation electron microscopy]]<ref>{{cite journal|doi=10.1088/0953-8984/19/45/455202|title=Real space information from fluctuation electron microscopy: Applications to amorphous silicon|year=2007|last1=Biswas|first1=Parthapratim|last2=Atta-Fynn|first2=Raymond|last3=Chakraborty|first3=S|last4=Drabold|first4=D A|journal=Journal of Physics: Condensed Matter|volume=19|issue=45|pages=455202|arxiv = 0707.4012 |bibcode = 2007JPCM...19S5202B }}</ref> in combination with [[Density of states]] modeling<ref>{{cite journal|doi=10.1103/PhysRevB.63.235207|title=Realistic models of paracrystalline silicon|year=2001|last1=Nakhmanson|first1=S.|last2=Voyles|first2=P.|last3=Mousseau|first3=Normand|last4=Barkema|first4=G.|last5=Drabold|first5=D.|journal=Physical Review B|volume=63|issue=23|bibcode = 2001PhRvB..63w5207N }}</ref> of electronic and vibrational states.

==Paracrystalline model==
[[File:Silica.svg|thumb|Structure of silica – an example of a paracrystalline, or partially disordered lattice]]
The paracrystalline model is a revision of the [[Continuous Random Network]] model first proposed by W. H. Zachariasen in 1932.<ref>{{cite journal|author=Zachariasen, W.H.|journal=J. Am. Chem. Soc.|volume=54|year=1932|pages= 3841|doi=10.1021/ja01349a006|issue=10|title=The Atomic Arrangement in Glass}}</ref> The paracrystal model is defined as highly strained, microcrystalline grains surrounded by fully amorphous material.<ref>Cowley, J.M. (1981) ''Diffraction Studies on Non-Crystalline Substances'', I. Hargittai and W. J. Orville Thomas (eds.). Akademia Kiado, Budapest, p. 13</ref> This is a higher energy state than the continuous random network model. The important distinction between this model and the microcrystalline phases is the lack of defined grain boundaries and highly strained lattice parameters, which makes calculations of molecular and lattice dynamics difficult. A general theory of paracrystals has been formulated in a basic textbook,<ref>Hosemann R., Bagchi R.N. (1962) ''Direct analysis of diffraction by matter'', North-Holland Publs., Amsterdam – New York</ref> and then further developed/refined by various authors.

==Applications==
The paracrystal model has been useful, for example, in describing the state of partially amorphous semiconductor materials after deposition. It has also been successfully applied to synthetic polymers, liquid crystals, biopoloymers, and biomembranes.<ref>
{{cite journal|author=Baianu I.C.|title= X-ray scattering by partially disordered membrane systems|journal=Acta Cryst. A|volume=34|year=1978|pages= 751–753|doi=10.1107/S0567739478001540|issue=5|bibcode = 1978AcCrA..34..751B }}</ref>

==See also==
* [[X-ray scattering]]
* [[Amorphous solid]]
* [[Single Crystal]]
* [[Polycrystalline]]
* [[Crystallography]]
* [[DNA]]
* [http://commons.wikimedia.org/wiki/File:ABDNAxrgpj.jpg X-ray pattern of a B-DNA Paracrystal]

==References==
{{reflist}}

[[Category:Phases of matter]]

Holographic algorithm - Revision history

en>Monkbot: Fix CS1 deprecated date parameter errors