Low temperature crystal structure of polyethylene: Results from a neutron diffraction study and from potential energy calculations

Avitabile, G.; Napolitano, Roberto; Pirozzi, Beniamino; Rouse, K. D.; Thomas, M.; Willis, B. T. M.

doi:10.1002/pol.1975.130130607

Cited by 117 publications

(67 citation statements)

References 5 publications

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“…The GGA geometry for this simulated single chain is also listed in Table I. In that table we verify that LDA grossly underestimates the interchain distances and the lattice constants, but that GGA corrects most of the LDA deficiencies and predicts interchain parameters and the cell volume in good agreement with the x-ray 33,34 and neutron 35 scattering results. Both GGA and LDA give good results for intrachain geometry, the errors being smaller than a few percent.…”

Section: Geometries Under Zero Pressuresupporting

confidence: 68%

“…In each unit cell, there are four (CH) 2 groups situated in two polymer chains. The LDA and GGA optimized geometrical parameters, including the bond lengths, the bond angles and the setting angle of the chain as well as the lattice vectors are listed in Table I together with the experimental results [33][34][35] and the other theoretical predictions 36,37,21,24 for both the single chain and the crystalline system. For reasons of numerical stability that will be discussed below, the GGA geometry is actually obtained at a pressure of 0.1 GPa which is sufficiently small in comparison with the pressure steps of 2 GPa used in this article.…”

Section: Geometries Under Zero Pressurementioning

confidence: 99%

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Density functional calculations on the structure of crystalline polyethylene under high pressures

Miao

Zhang

Doren

et al. 2001

The Journal of Chemical Physics

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Structural and vibrational properties of solid nitromethane under high pressure by density functional theory J. Chem. Phys. 124, 124501 (2006); 10.1063/1.2179801 This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation. The geometrical structures of the crystalline polyethylene under several different external pressures up to 10 GPa are optimized by a pseudopotential plane wave density functional method. Both local density ͑LDA͒ and generalized gradient ͑GGA͒ approximations for exchange-correlation energy and potential are used. It is found that LDA heavily underestimate the geometry parameters under ambient pressure but GGA successfully correct them and get results in good agreements with the experimental geometry. The calculated GGA volume is about 94 Å 3 in comparison with the x-ray scattering value of about 92 Å 3 and the neutron scattering value of 88 Å 3 . The bulk and Young's modulus are calculated by means of several different methods. The Young's modulus along the chain ranges from about 350 to about 400 GPa which is in good agreement with the experimental results. But the bulk modulus is several times larger than those of experiments, indicating a different description of the interchain interactions by both LDA and GGA. The band structures are also calculated and their changes with the external pressure are discussed.

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Section: Geometries Under Zero Pressuresupporting

confidence: 68%

Section: Geometries Under Zero Pressurementioning

confidence: 99%

Density functional calculations on the structure of crystalline polyethylene under high pressures

Miao

Zhang

Doren

et al. 2001

The Journal of Chemical Physics

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“…From this energy curve the equilibrium unit cell length can be extracted as well as the second derivative of the energy at equilibrium length. The value of co is found to be 2.53% which is less than 1% smaller than the experimental value at 4K (co = 2.548A) [6]. Eq.…”

Section: The Elastic Modulusmentioning

confidence: 87%

“…The a-axis and b-axis, perpendicular to the chain direction (caxis), are fixed at the experimental values measured at a temperature of 4 K (a = 7.12 A and b = 4.85 A) [6], as no temperature effects are included. The caxis is optimized (c = 2.53 A).…”

Section: Jcl Hageman Et Al/computational Materials Science 10 (19mentioning

confidence: 99%

Ultra strong polymer fibers: Ab initio calculations on polyethylene

Hageman

Groot

Meier

1998

Computational Materials Science

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“…The unit cell parameters at a temperature of 4 K are a × b × c ) 7.12 × 4.85 × 2.55 Å 3 . 20 The setting angle φ is 42°. 21 The Young modulus of the crystalline orthorhombic polyethylene is calculated for E cut ) 54 Ry.…”

Section: Basis Set Convergencementioning

confidence: 99%

Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

et al. 1997

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The Young modulus for crystalline polyethylene is calculated using ab initio molecular dynamics based on density functional theory in the local density approximation (DFT-LDA). This modulus, which can be seen as the ultimate value for the Young modulus of polyethylene fibers, is found to be 334 GPa. For the first time the modulus is evaluated ab initio (no bias from experimental data) with demonstrated basis set convergence.

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Low temperature crystal structure of polyethylene: Results from a neutron diffraction study and from potential energy calculations

Cited by 117 publications

References 5 publications

Density functional calculations on the structure of crystalline polyethylene under high pressures

Density functional calculations on the structure of crystalline polyethylene under high pressures

Ultra strong polymer fibers: Ab initio calculations on polyethylene

Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

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