RESUMO
The electrochemical oxidation of a transition metal oxide through calcium extraction is achieved for the first time. The 1D framework of Ca3Co2O6 is maintained upon oxidation and the new phase formed exhibits a modulated structure. The process occurs at high potential and is partially reversible, which opens prospects for a calcium battery proof-of-concept.
RESUMO
A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to â¼3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress.
RESUMO
Time-dependent Schrödinger equation, TDSE, simulations have been performed in order to prepare and study via MPIPS the evolution of vibrational wave packets on the ion pair electronic state potentials B''B1Sigma(u)(+) and Hh1Sigma(g)(+) of the H2 molecule. Using ab initio potential surfaces and transition moments, we present two- and three-photon excitation schemes with ultrashort pulses (tau