相关论文: Molecular Dynamics Simulations of NMR Relaxation a…
The glass transition is a long-standing unsolved problem in materials science. For polymers, our understanding of glass-formation is particularly poor due to the added complexity of chain connectivity and flexibility; structural relaxation…
By means of computer simulations and solution of the equations of the Mode Coupling Theory (MCT), we investigate the role of the intramolecular barriers on several dynamic aspects of non-entangled polymers. The investigated dynamic range…
The surface a thin-film is attached to and the surrounding monolayer causes geometrical confinement of a interrogated molecule; we look at the base case of a SC$_{18}H_{37}$ in a SC$_{18}H_{37}$ monolayer on Au[111]. Normal mode analysis…
The NMR relaxation rate and the static spin susceptibility in graphene are studied within a tight-binding description. At half filling, the NMR relaxation rate follows a power law as $T^2$ on the particle-hole symmetric side, while with a…
Atomistic (atom-scale) and coarse-grained (meso-scale) simulations of structure and dynamics of poly-isoprene melts are compared. The local structure and chain packing is mainly determined by the atomistic details of the polymer…
The velocity auto-correlation spectra of simple liquids obtained by the NMR method of modulated gradient spin echo show features in the low frequency range up to a few kHz, which can be explained reasonably well by a $t^{-3/2}$ long time…
We investigated the static and dynamic properties of a Rouse ring polymer modified by introducing an effective, spherically symmetric, attractive potential of entropic nature and a memory function describing the effect of dynamic…
Significant progress was made in recent years in the understanding of the proton spin kinetics in polymer melts. Generally, the proton spin kinetics is determined by intramolecular and intermolecular magnetic dipole-dipole contributions of…
Nonequilibrium molecular dynamics simulations are used to study the deformation behavior of disperse polymer melts by tracking test chains of length N = Mw, the weight average molecular weight, in melts of varying dispersity. At high strain…
We investigate the time autocorrelation of the molecular magnetization $M(t)$ for three classes of magnetic molecules (antiferromagnetic rings, grids and nanomagnets), in contact with the phonon heat bath. For all three classes, we find…
Diffusion studies using nuclear magnetic resonance (NMR) spectroscopy were conducted on two model surfactant solutions of cetyltrimethylammonium bromide/sodium salicylate (CTAB/NaSal) and cetylpyridinium chloride/sodium salicylate…
The molecular dynamics of regioregulated poly(3-hexylthiophene) P3HT is investigated using muon spin relaxation ($\mu$SR). The response of the $\mu$SR spectra to a longitudinal magnetic field ($B_{\rm LF}$, parallel to the initial muon spin…
We report extensive simulations of the relaxation dynamics of a self-avoiding polymer confined inside a cylindrical pore. In particular, we concentrate on examining how confinement influences the scaling behavior of the global relaxation…
We study structural properties of a ring polymeric melt confined in a film in comparison to a linear counterpart using molecular dynamics simulations. Local structure orderings of ring and linear polymers in the vicinity of the surface are…
Polymers near the glass transition temperature Tg often exhibit a breakdown of time-temperature-superposition (TTS), with chain relaxation times and viscosity exhibiting a weaker temperature dependence than segmental relaxation times. The…
The proton nuclear spin-lattice relaxation rate 1/T1 has been measured as a function of temperature and magnetic field (up to 15 T) in the molecular magnetic ring Fe10. Striking enhancement of 1/T1 is observed around magnetic field values…
The vibrational frequency of hydrogen molecules has been observed to increase strongly with He concentration in helium hydrogen fluid mixtures. This has been associated with He-H interactions, either directly through chemical bonding, or…
Among the different dynamical processes that take place in polymers, methyl group rotation is perhaps the simplest one, since all the relevant interactions on the methyl group can be condensed in an effective mean-field one-dimensional…
The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However,…
The NMR relaxation rate $1/T_{1}$ is studied for one-dimensional multicomponent spin-orbital systems. By combining the bosonization techniques and the exact solution of the SU($n$) model, we evaluate the power-law exponent and the…