http://www.cnr.it/ontology/cnr/individuo/prodotto/ID54376

Formumation of improved basis sets for the study of polymer dynamics through diffusion theory methods (Articolo in rivista)

Type

Articolo in rivista (Classe)
Prodotto della ricerca (Classe)

Label

Formumation of improved basis sets for the study of polymer dynamics through diffusion theory methods (Articolo in rivista) (literal)

Anno

2008-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1063/1.2936843 (literal)

Alternative label

Gaspari R.; Rapallo A. (2008)
Formumation of improved basis sets for the study of polymer dynamics through diffusion theory methods
in The Journal of chemical physics; American Institute Of Physics (AIP), Melville (Stati Uniti d'America)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Gaspari R.; Rapallo A. (literal)

Pagina inizio

244109-1 (literal)

Pagina fine

244109-15 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url

http://jcp.aip.org/resource/1/jcpsa6/v128/i24/p244109_s1 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

128 (literal)

Rivista

?The ?Journal of chemical physics (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

24 (literal)

Note

Scopu (literal)
ISI Web of Science (WOS) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

ISMAC-CNR Milano (literal)

Titolo

Formumation of improved basis sets for the study of polymer dynamics through diffusion theory methods (literal)

Abstract

In this work a new method is proposed for the choice of basis functions in diffusion theory (DT) calculations. This method, named hybrid basis approach (HBA), combines the two previously adopted long time sorting procedure (LTSP) and maximum correlation approximation (MCA) techniques; the first emphasizing contributions from the long time dynamics, the latter being based on the local correlations along the chain. In order to fulfill this task, the HBA procedure employs a first order basis set corresponding to a high order MCA one and generates upper order approximations according to LTSP. A test of the method is made first on a melt of cis-1,4-polyisoprene decamers where HBA and LTSP are compared in terms of efficiency. Both convergence properties and numerical stability are improved by the use of the HBA basis set whose performance is evaluated on local dynamics, by computing the correlation times of selected bond vectors along the chain, and on global ones, through the eigenvalues of the diffusion operator L. Further use of the DT with a HBA basis set has been made on a 71-mer of syndiotactic trans-1,2-polypentadiene in toluene solution, whose dynamical properties have been computed with a high order calculation and compared to the \"numerical experiment\" provided by the molecular dynamics (MD) simulation in explicit solvent. The necessary equilibrium averages have been obtained by a vacuum trajectory of the chain where solvent effects on conformational properties have been reproduced with a proper screening of the nonbonded interactions, corresponding to a definite value of the mean radius of gyration of the polymer in vacuum. Results show a very good agreement between DT calculations and the MD numerical experiment. This suggests a further use of DT methods with the necessary input quantities obtained by the only knowledge of some experimental values, i.e., the mean radius of gyration of the chain and the viscosity of the solution, and by a suitable vacuum trajectory, with great savings in computational time required. This offers a theoretical bridge between the experimental static and dynamical properties of polymers. (literal)

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