On the separation between torsion-vibration and conformational relaxation processes in the incoherent intermediate scattering function of polyethylene

Arialdi, G; Ryckaert, J-P; Theodorou, DN

dc.contributor.author	Arialdi, G	en
dc.contributor.author	Ryckaert, J-P	en
dc.contributor.author	Theodorou, DN	en
dc.date.accessioned	2014-03-01T01:19:23Z
dc.date.available	2014-03-01T01:19:23Z
dc.date.issued	2003	en
dc.identifier.issn	0301-0104	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15454
dc.subject	α-Relaxation	en
dc.subject	Local dynamics	en
dc.subject	Molecular dynamics simulation	en
dc.subject	Polyethylene	en
dc.subject	Quasi-elastic neutron scattering	en
dc.subject	Torsion-vibration process	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.classification	Physics, Atomic, Molecular & Chemical	en
dc.subject.other	hydrogen	en
dc.subject.other	polyethylene	en
dc.subject.other	article	en
dc.subject.other	conformational transition	en
dc.subject.other	correlation function	en
dc.subject.other	crystallization	en
dc.subject.other	diffusion	en
dc.subject.other	molecular dynamics	en
dc.subject.other	neutron scattering	en
dc.subject.other	qualitative analysis	en
dc.subject.other	quantitative analysis	en
dc.subject.other	temperature	en
dc.subject.other	vibration	en
dc.title	On the separation between torsion-vibration and conformational relaxation processes in the incoherent intermediate scattering function of polyethylene	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0301-0104(03)00174-5	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0301-0104(03)00174-5	en
heal.language	English	en
heal.publicationDate	2003	en
heal.abstract	We present a detailed study of the local dynamics of short polyethylene (PE) chains in a wide temperature range (T = 350 450, 504 K) using molecular dynamics (MD) simulations based on a united atom model. Undercooled melt phases can be studied easily in simulations without any sign of crystallization in the sample. We focus on the interpretation of the incoherent intermediate scattering function in the range 0.375 less than or equal to Q less than or equal to 2.0 Angstrom(-1) using a refined analysis of the time correlation functions in terms of a continuous linear combination of exponential decays weighted by a distribution of relaxation times (DRT). At 350 K, over the whole Q range investigated, the relaxation of the intermediate scattering function is due to a combination of a fast process occurring on the picosecond time scale and a slow process. The faster process is weakly Q- and T-dependent and is shown to originate from torsion vibration motions. The DRT associated with the slow process, related to conformational jumps, changes quantitatively and qualitatively in the explored Q range and does not resemble a stretched exponential behaviour. The average global relaxation time related to the slow process evolves below Q = 1 Angstrom(-1) towards a Q(-3.3) power law behaviour. (C) 2003 Elsevier Science B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Chemical Physics	en
dc.identifier.doi	10.1016/S0301-0104(03)00174-5	en
dc.identifier.isi	ISI:000184511200028	en
dc.identifier.volume	292	en
dc.identifier.issue	2-3	en
dc.identifier.spage	371	en
dc.identifier.epage	382	en