Band alignment at InP/TiOinterfaces from density-functional theory.

The natural band alignments between indium phosphide and the main dioxides of titanium, i.e. rutile, anatase, and brookite as well as amorphous titania are calculated from the branch-point energies of the respective materials.

Assignment of a Physical Energy Scale for the Dimensionless Interaction Energies within the PRIME20 Peptide Model.

We present a calibration scheme to determine the conversion factors from a coarse-grained stochastic approximation Monte Carlo approach using the PRIME20 peptide interaction model to atomistic force-field interaction energies at full explicit aqueous solvation. The conversion from coarse-grained to atomistic structures was performed according to our previously established inverse coarse-graining protocol. We provide a physical energy scale for both the backbone hydrogen bonding interactions and the sidechain interactions by correlating the dimensionless energy descriptors of the PRIME20 model with the energies averaged over molecular dynamics simulations.

Reverse Mapping of Coarse Grained Polyglutamine Conformations from PRIME20 Sampling.

An inverse coarse-graining protocol is presented for generating and validating atomistic structures of large (bio-) molecules from conformations obtained via a coarse-grained sampling method. Specifically, the protocol is implemented and tested based on the (coarse-grained) PRIME20 protein model (P20/SAMC), and the resulting all-atom conformations are simulated using conventional biomolecular force fields. The phase space sampling at the coarse-grained level is performed with a stochastical approximation Monte Carlo approach.

Coexistence of Cationic and Anionic Phosphate Moieties in Solids: Unusual but Not Impossible.

Phosphoric acid is commonly known either as a neutral molecule or as an anion (phosphate). We theoretically confirm by ab initio molecular dynamics simulations (AIMD) that a cationic form HPO coexists with the anionic form HPO in the same salt. This paradoxical situation is achieved by partial substitution of Cs by HPO in CsHPO.

Acute Bite Angle POP- and PSP-Type Ligands and Their Trinuclear Copper(I) Complexes: Synthesis and Photo-Luminescence Properties.

In the current work, the rational synthesis of trinuclear copper complexes, incorporating acute bite angle POP- and PSP-type ligands, is reported. The in situ formation of POP (PhP-O-PPh) or PSP (PhP-S-PPh) ligands in the presence of a copper(I) precursor gave access to various trinuclear copper complexes of the form [Cu(μ-Hal)(μ-PXP)]PF [X = O; Hal = Cl (), Br (), I () and X = S; Hal = Cl (), Br (), I ()]. Related iodide-containing complexes and clusters, such as [Cu(μ-I)(PhPI)] () and [Cu(μ-I)(μ-I)(μ-PSP)] (), could also be obtained via the variation of the reaction stoichiometry.

ab-Initio Study of Hydrogen Bond Networks in 1,2,3-Triazole Phases.

The research in storage and conversion of energy is an everlasting process. The use of fuel cells is very tempting but up to now there are still several conceptual challenges to overcome. Especially, the requirement of liquid water causes difficulties due to the temperature limit.

Exploring non-equilibrium molecular dynamics of mobile protons in the solid acid CsHPO at the micrometer and microsecond scale.

We explicitly compute the non-equilibrium molecular dynamics of protons in the solid acid CsHPO on the micrometer length scale via a multiscale Markov model: The molecular dynamics/matrix propagation (MDM) method. Within the MDM approach, the proton dynamics information of an entire molecular dynamics simulation can be condensed into a single M × M matrix (M is the number of oxygen atoms in the simulated system). Due to this drastic reduction in the complexity, we demonstrate how to increase the length and time scales in order to enable the simulation of inhomogeneities of CsHPO systems at the nanometer scale.

Dynamical matrix propagator scheme for large-scale proton dynamics simulations.

We derive a matrix formalism for the simulation of long range proton dynamics for extended systems and timescales. On the basis of an ab initio molecular dynamics simulation, we construct a Markov chain, which allows us to store the entire proton dynamics in an M × M transition matrix (where M is the number of oxygen atoms). In this article, we start from common topology features of the hydrogen bond network of good proton conductors and utilize them as constituent constraints of our dynamic model.

Effect of anion reorientation on proton mobility in the solid acids family CsHXO (X = S, P, Se, y = 1, 2) from ab initio molecular dynamics simulations.

The high temperature phases of the solid acids CsHSeO, CsHSO and CsHPO show extraordinary high proton conductivities, while the low temperature phases do not conduct protons at all. We systematically investigate proton dynamics in the low and high temperature phases of these compounds by means of ab initio molecular dynamics simulations in order to develop a general picture of the proton transfer mechanism. For all of these compounds, proton conduction follows a Grotthuss mechanism via a combined proton transfer and subsequent structural reorientation of the environment.

Efficient representation of the linear density-density response function.

We present a thorough derivation of the mathematical foundations of the representation of the molecular linear electronic density-density response function in terms of a computationally highly efficient moment expansion. Our new representation avoids the necessities of computing and storing numerous eigenfunctions of the response kernel by means of a considerable dimensionality reduction about from 10 to 10 . As the scheme is applicable to any compact, self-adjoint, and positive definite linear operator, we present a general formulation, which can be transferred to other applications with little effort.

Proton mobility in aqueous systems: combining ab initio accuracy with millisecond timescales.

We present a multiscale simulation of proton transport in liquid water, combining ab initio molecular dynamics simulations with force-field ensemble averaging and kinetic Monte-Carlo simulations. This unique Ansatz allows for ab initio accuracy incorporating the femtosecond dielectric relaxation dynamics of the aqueous hydrogen bonding network, and bridges the time-scale gap towards the explicit simulation of millisecond diffusion dynamics.

Generalization of the electronic susceptibility for arbitrary molecular geometries.

We generalize the explicit representation of the electronic susceptibility χ[R](r, r') for arbitrary molecular geometries R. The electronic susceptibility is a response function that yields the response of the molecular electronic charge density at linear order to an arbitrary external perturbation. We address the dependence of this response function on the molecular geometry.