Basis set generation for quantum dynamics simulations using simple trajectory-based methods

Methods for solving the time-dependent Schrödinger equation generally employ either a global static basis set, which is fixed at the outset, or a dynamic basis set, which evolves according to classical-like or variational equations of motion; the former approach results in the well-known exponential scaling with system size, while the latter can suffer from challenging numerical problems, such as singular matrices, as well as violation of energy conservation. Here, we suggest a middle road: building a basis set using trajectories to place time-independent basis functions in the regions of phase space relevant to wave function propagation. This simple approach, which potentially circumvents many of the problems traditionally associated with global or dynamic basis sets, is successfully demonstrated for two challenging benchmark problems in quantum dynamics, namely, relaxation dynamics following photoexcitation in pyrazine, and the spin Boson model

Recycling of oxygen liberated from decomposition of hydrogen peroxide during cobalt (II)-catalysed oxidation of benzyl alcohol

723-725The reaction of benzyl alcohol with hydrogen peroxide is catalysed by cobalt (II) acetate and leads to exclusive formation of benzaldehyde. No benzoic acid is formed under the reaction conditions described. During the oxidation oxygen is liberated from hydrogen peroxide via an independent parallel process and it can be recycled to take part in the oxidation. Toluene reacts with hydrogen peroxide and cobalt (II) acetate at 70o C to give benzyl alcohol and benzaldehyde as the major products

Synthesis and characterization of poly(p-phenylenediamine): TiO2 nanocomposites and investigation of conducting properties for optoelectronic application

Poly(p-phenylenediamine) is a potential precursor for designing of new materials for optoelectronic application. Synthesis and characterization of poly(p-phenylenediamine) – TiO2 nanocomposites has been demonstrated. Structural change observed due to the formation of nanocomposites was correlated with concomitant change in conducting behavior of the parent polymer. Polymer nanocomposite was synthesized through an in-situ oxidative polymerization technique with simultaneous dispersion of TiO2 nanoparticles. TiO2 nanoparticles were synthesized via sol-gel process. Structural characterization was accomplished by using conventional spectroscopic and imaging techniques. I-V measurement of the nanocomposites revealed that the nearly nonconducting poly(p-phenylenediamine) after structural modification exhibits conductivity of 10−6 S/cm leading to formation of wide band gap semiconducting materials

Thermoelectric switch from anilinic compounds

521-524Copper(II) ion can be embedded in the aggregates formed by anilinic compounds, such as 2,4-dimethoxyaniline, 2-aminophenol, 4-aminophenol, protonated polyaniline, through a reaction of catalytic amounts of copper complexes such as cis-bis (glycinato)copper(II) monohydrate and copper(II) acetate in the presence of hydrogen peroxide. These aggregates have the property of an irreversible thermoelectric switch.</span

Synthesis and characterization of electroactive films deposited from aniline dimers

The electrochemical oxidation of the aniline dimers 2-aminodiphenylamine (2-adpa) and 4-aminodiphenylamine (4-adpa) has been performed in strongly acidic medium on platinum, graphite, and indium tin oxide electrodes. The resulting films have been characterized by a number of electrochemical, microscopic, and spectroscopic techniques in order to gain some insight on their respective chemical structures. Both poly(2-adpa) and poly(4-adpa) are electroactive species which differ significantly one from another. It was found that aged poly(4-adpa)displayed electrochemical, morphologic and spectroscopic characteristics similar to those shown by polyaniline. On the contrary, poly(2-adpa) is really a mixture of three oligomerization products. The two main oligomers contain both open-ring and cycled phenazine centers, although their chemical structures seem to differ in the cap-end of the chain growth. The third oligomer is a minor product which seems a highly symmetric macrocycle involving several 2-adpa molecules.This work has been cofinanced by the European Commission (ERDF funds) and the Spanish Ministerio de Educación y Cultura (MAT2004-01479). University of Alicante assisted in meeting the publication costs of this article