Abstract We present an improved algorithm of the self‐consistent mean‐field implementation that has been recently proposed for calculation block copolymer self‐assembly. Without requiring prior knowledge symmetry mesophase segregation, is numerically stable and significantly faster than previously methods. These advantages provide a valuable tool combinatorial screening novel metastable structural phases copolymers. apply method demonstrate complex mesophases in linear, asymmetric triblock...

Abstract A method that utilises atomic trajectories and velocities from molecular dynamics simulations has been suitably adapted employed for the implicit calculation of phonon dispersion curves graphene. Classical potentials widely used in literature were employed. Their performance was assessed each individual branch overall dispersion, using available inelastic x-ray scattering data. The is promising systems with large scale periodicity, accounts anharmonic effects non-bonding...

Bond stretching and angle bending force fields, appropriate to describe in-plane properties of graphene sheets, are derived using first principles' methods. The obtained fields fitted by analytical anharmonic potential energy functions, providing efficient means calculations in molecular mechanics simulations. Using both dynamics simulations methods, numerical results regarding the mechanical behavior monolayers under various loads, like uniaxial tension different directions or hydrostatic...

Thin membranes, such as monolayer graphene of monoatomic thickness, are bound to exhibit lateral buckling under uniaxial tensile loading that impairs its mechanical behaviour. In this work, we have developed an experimental device subject 2D materials controlled equibiaxial strain on supported beams can be flexed up or down the material either compression tension, respectively. Using gauges in tandem with Raman spectroscopy measurements, monitor G and phonon properties biaxial thus extract...

We investigate polaron properties in the semiclassical Holstein model one, two, and three dimensions, using two methods: a simple efficient numerical scheme variational approach. obtain accurate information on energy existence regimes of state. study small oscillations through normal-mode analysis, their stability, evaluate density states eigenfrequencies for different system parameters. The analysis shows one-dimensional case pinning-breathing mode crossing transition region to large...

We investigate propagation of a charge carrier along intrinsically dynamically disordered double-stranded DNA. This is realized by the semiclassical coupling with nonlinear lattice model that can accurately describe statistical mechanics large amplitude fluctuations base pairs leading to thermal denaturation transition find fluctuating intrinsic disorder trap and inhibit polaronic transport. The dependence mean distance covered until its trapping, as function energy also presented.

We report results showing that thermally-induced openings of double stranded DNA coincide with the location functionally relevant sites for transcription. Investigating both viral and bacterial gene promoter segments, we found most probable opening occurs at transcription start site. Minor appear to be related other regulatory sites. Our suggest coherent thermal fluctuations play an important role in initiation Essential elements dynamics, addition sequence specificity, are nonlinearity...

The pressure evolution of the Raman spectrum graphene grown by chemical vapor deposition on polycrystalline copper is investigated with use polar and nonpolar transmitting media (PTM). $G$ 2$D$ bands exhibit similar slopes for both PTM irrespective any unintentional initial doping and/or strain samples. Our analysis suggests that pressure-induced charge transfer effects are too small to influence response graphene; rather, it determined compressibility substrate interaction PTM. For PTM, a...

We study temperature effects on the characteristic time for which charge carriers remain spatially confined while interacting with fluctuational openings (bubbles) of double stranded DNA. Using semiclassical molecular-dynamics simulations, we find that in low-temperature regime this decreases a power-law fashion and coincides polaronic lifetime. However, above 50–70 K confinement exhibits an exponential increase temperature. demonstrate enhanced trapping is result intrinsic dynamical...

We present the ac response of a DNA charge transport model, where in $\ensuremath{\pi}$-stack interacts with base-pair opening dynamics double strand. The calculated conductivity exhibits prominent peaks at polaron normal modes electronic character, while weaker appears lower frequencies vibrational part mode spectrum. Examples former, strong peaks, show redshifts as amplitude field increases.

We examine the mechanical response of single layer graphene nanoribbons (GNR) under constant compressive loads through molecular dynamics simulations. Compressive stress-strain curves are presented for GNRs various lengths and widths. The dependence GNR's buckling resistance on its size, aspect ratio, chiral angle is discussed approximate corresponding relations provided. A master curve describing critical stress their ratio presented. Our findings were compared to continuum elasticity...

We discuss the effect of heterogeneity on chaotic properties Peyrard-Bishop-Dauxois nonlinear model DNA. Results are presented for maximum Lyapunov exponent and deviation vector distribution. Different compositions adenine-thymine (AT) guanine-cytosine (GC) base pairs examined various energies up to melting point corresponding sequence. also consider alternation index, which measures DNA chain through number alternations between different types (AT or GC) pairs, behavior system. Biological...

The distribution of bubble lengths in double-stranded DNA is presented for segments varying guanine−cytosine (GC) content, obtained with Monte Carlo simulations using the Peyrard−Bishop−Dauxois model at 310 K. An analytical description whole regime investigated, i.e., up to widths order tens nanometers, available. We find that decay and characteristic exponents this show two distinct regimes as a function GC content. observed attributed anharmonic interactions within base pairs. results are...

We present analytical relations for the quantum evolution of number difference bosons between two sites a double-well potential, by using perturbative results small tunneling amplitudes in two-mode approximation. Results are obtained different initial conditions: completely localized states and coherent spin states. In former case both short long time behavior is investigated characteristic Bohr frequencies energy spectrum determined. latter we calculate time-scale difference. The...

A number of experimental and theoretical works have suggested the relevance polaronic effects for charge migration in DNA. We previously introduced Peyrard-Bishop-Holstein model as an appropriate description such effects. The polaron normal modes are expected to manifest themselves through response system external time-periodic field. Here, following a brief presentation solutions their energies model, we report these discuss complete density states eigenfrequencies its dependence on...

We present numerical results on the temperature dependence of distribution bubble lengths in DNA segments various guanine-cytosine (GC) concentrations. Base-pair openings are described by Peyrard–Bishop–Dauxois model and corresponding thermal equilibrium distributions bubbles obtained through Monte Carlo calculations for sizes up to order a hundred base pairs. The parameters length GC content is investigated. provide simple expressions which approximately describe these relations. variation...

The mechanical response of single and multiple graphene sheets under uniaxial compressive loads was studied with molecular dynamics (MD) simulations, using different semi-empirical force fields at boundary conditions or constrains. Compressive stress–strain curves were obtained the critical stress/strain values derived. MD results are compared to linear elasticity continuum theory for loaded slabs. Concerning length dependence values, qualitatively similar behavior is observed between...

We report that few graphene flakes embedded into polymer matrices can be mechanically stretched to relatively large deformation (>1%) in an efficient way by adopting a particular ladder-like morphology consisting of consecutive mono-, bi-, tri-, and four-layer units. In this type flake architecture, all the layers adhere surrounding inducing similar on individual layers, preventing interlayer sliding optimizing strain transfer efficiency. have exploited Raman spectroscopy quantify effect...

Analytical expressions for the energy eigenstates of boson-Hubbard (or quantum discrete-nonlinear Schr\"odinger) dimer are obtained by applying perturbation theory in small-tunneling-amplitude limit. The results relevant a Bose-Einstein condensate trapped double-well potential. A detailed comparison with numerical solutions arising from direct diagonalization Hamiltonian (for even or odd numbers bosons) is presented, and limits validity perturbative determined. For fixed values tunneling...

A Bose-Einstein condensate trapped in a two-dimensional optical lattice exhibits an abrupt transition manifested by the macroscopic wave function changing character from spatially localized to extended. Resulting bifurcation, this irreversible takes place as interwell potential barrier is adiabatically decreased below critical value. This sharp contrast corresponding one-dimensional case where such bifurcation absent and extent of mode continuously tunable. We demonstrate how these phenomena...