The COMPASS force field: parameterization and validation for phosphazenes

Sun, Huai; Ren, Pengyu; Fried, Joel

doi:10.1016/s1089-3156(98)00042-7

Cited by 1,297 publications

(616 citation statements)

References 64 publications

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“…1. In the molecular dynamics simulation performed by MATERIALS STUDIO, the interatomic interactions are described by the COMPASS force field ͑condensed-phased optimized molecular potential for atomistic simulation studies͒, 9,16,17 which has been proven to be applicable for describing the mechanical properties of carbon materials. The MDS is carried out at room temperature.…”

Section: MD Calibration Of E 0 and Discussionmentioning

confidence: 99%

Calibration of nonlocal scaling effect parameter for free vibration of carbon nanotubes by molecular dynamics

Duan¹,

Wang²,

Zhang³

2007

Journal of Applied Physics

339

148

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In this paper, the small scaling parameter e0 of the nonlocal Timoshenko beam theory is calibrated for the free vibration problem of single-walled carbon nanotubes (SWCNTs). The calibration exercise is performed by using vibration frequencies generated from molecular dynamics simulations at room temperature. It was found that the calibrated values of e0 are rather different from published values of e0. Instead of a constant value, the calibrated e0 values vary with respect to length-to-diameter ratios, mode shapes, and boundary conditions of the SWCNTs. In addition, the physical meaning of the scaling parameter is explored. The results show that scaling parameter assists in converting the kinetic energy to the strain energy, thus enabling the kinetic energy to be equal to the strain energy. The calibrated e0 presented herein should be useful for researchers who are using the nonlocal beam theories for analysis of micro and nano beams/rods/tubes.

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Section: MD Calibration Of E 0 and Discussionmentioning

confidence: 99%

Calibration of nonlocal scaling effect parameter for free vibration of carbon nanotubes by molecular dynamics

Duan¹,

Wang²,

Zhang³

2007

Journal of Applied Physics

339

148

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“…20,21 Most parameters of this force field are derived from ab initio calculations and later optimized empirically to yield good agreement with experiments. As for many force fields, the functional form is divided in two different contributions, namely bonded and nonbonded terms.…”

Section: Molecular Dynamics Simulationsmentioning

confidence: 99%

Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

Busselez

Arbe

Álvarez

et al. 2011

The Journal of Chemical Physics

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Oxygen and nitrogen plasma hydrophilization and hydrophobic recovery of polymers Biomicrofluidics 6, 016501 (2012) Interferometric scanning microscopy for the study of disordered materials Appl. Phys. Lett. 99, 251912 (2011) (Electro)mechanical behavior of selectively solvated diblock/triblock copolymer blends Appl. Phys. Lett. 99, 242901 (2011) Statics of polymer droplets on deformable surfaces J. Chem. Phys. 135, 214703 (2011) Interactions between polymer brush-coated spherical nanoparticles: The good solvent case J. Chem. Phys. 135, 214902 (2011) Additional information on J. Chem. Phys. Quasielastic neutron scattering, x-ray diffraction measurements, and fully atomistic molecular dynamics simulations have been performed on poly(vinylpyrrolidone) homopolymer above its glass transition temperature. A "prepeak" appears in the x-ray diffraction pattern that shows the typical features of a first amorphous halo. From an effective description of the experimentally accessed incoherent scattering function of hydrogens in terms of a stretched exponential function, we observe enhanced stretching and a momentum-transfer dependence of the characteristic time different from that usually reported for more simple polymers (main-chain polymers or polymers with small side groups). The comparison with both kinds of experimental results has validated the simulations. The analysis of the simulated structure factor points to a nanosegregation of side groups (SG) and mainchains (MC). The detailed insight provided by the simulations on the atomic trajectories reveals a partial and spatially localized decoupling of MC and SG dynamics at length scales between the average SG-SG distance and the characteristic length of the backbone interchain correlations. Anomalous behavior in correlators calculated for the SG subsystem are found, like e.g., logarithmiclike decays of the density-density correlation function. They might be a consequence of the existing large dynamic asymmetry between SG and MC subsystems. Our results suggest that, as the SGs are spatially extended and chemically different from the backbone, they form transient nanosegregated domains. The dynamics of these domains show similar behavior to that found in other systems displaying large dynamic asymmetry.

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“…Therefore, this force field enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermophysical properties that exist for a broad range of isolated molecules and in condensed phases, and under a wide range of conditions of temperature and pressure. [28][29][30][31][32][33][34] The model cubic cell was built by means of the Amorphous Cell Protocol, originally proposed by Theodorou and Suter. 35 We started from 12 different well equilibrated chains of 80 monomers each ͑14 424 atoms in total͒ and we constructed a cubic cell with periodic boundary conditions at 413 K and an initial density set to 0.79 g / cm 3 , which is the experimental value at that temperature 27 ͑Table I͒.…”

Section: A Fully Atomistic Molecular Dynamics Simulationsmentioning

confidence: 99%

Chain dynamics of poly(ethylene-alt-propylene) melts by means of coarse-grained simulations based on atomistic molecular dynamics

Pérez-Aparicio

Colmenero

Álvarez

et al. 2010

The Journal of Chemical Physics

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We present coarse-grained molecular dynamics simulations of poly͑ethylene-alt-propylene͒ ͑PEP͒ melts, ranging in chain length from about N e ͑the entanglement length͒ to N =6N e . The coarse-grained parameters, potential of mean force and bare friction, were determined from fully atomistic molecular dynamics simulations carried out on a PEP cell containing 12 chains of 80 monomers each and subjected to periodic boundary conditions. These atomistic simulations were previously validated by means of extensive neutron scattering measurements. Uncrossability constrains were also introduced in the coarse-grained model to prevent unphysical bond crossing. The coarse-grained simulations were carried out at 492 K and focus on chain dynamics. The results obtained were analyzed in terms of Rouse coordinates and Rouse correlators. We observe deviations from Rouse behavior for all chain lengths investigated, even when the chain stiffness is incorporated in the Rouse model. These deviations become more important as the chain length increases. The general scenario emerging from the results obtained is that the deviations from Rouse-like behavior are due to correlations among the forces acting upon a chain bead, which seem to be related with the constraint of uncrossability among the chains. As consequence, nonexponentiality of the Rouse correlators and mode-and time-dependent friction are observed. It seems that, in the molecular weight explored, these effects still give not raise to reptation behavior but to a crossover regime between Rouse and reptation. On the other hand, the results obtained are in qualitative agreement with those expected from the so-called generalized Rouse models, based on memory function formalisms.

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The COMPASS force field: parameterization and validation for phosphazenes

Cited by 1,297 publications

References 64 publications

Calibration of nonlocal scaling effect parameter for free vibration of carbon nanotubes by molecular dynamics

Calibration of nonlocal scaling effect parameter for free vibration of carbon nanotubes by molecular dynamics

Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

Chain dynamics of poly(ethylene-alt-propylene) melts by means of coarse-grained simulations based on atomistic molecular dynamics

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