Integração numérica de leis de velocidade diferenciais com o uso do SCILAB

In this work, we applied the free open source SCILAB software for the numerical integration of differential rate law equations to obtain the concentration profiles of chemical species involved in the kinetics of some complex reactions. An automated method was applied to construct the system of ordinary differential equations (ODE) from the postulated chemical models. The solutions of the ODEs were obtained numerically by standard SCILAB functions. We successfully simulated even complex chemical systems such as pH oscillators. This communication opens up the possibility of using SCILAB in simulations and modeling by our chemistry undergraduate students

Integração numérica de leis de velocidade diferenciais com o uso do SCILAB Numerical integration of differential rate laws by means of SCILAB

<abstract language="eng">In this work, we applied the free open source SCILAB software for the numerical integration of differential rate law equations to obtain the concentration profiles of chemical species involved in the kinetics of some complex reactions. An automated method was applied to construct the system of ordinary differential equations (ODE) from the postulated chemical models. The solutions of the ODEs were obtained numerically by standard SCILAB functions. We successfully simulated even complex chemical systems such as pH oscillators. This communication opens up the possibility of using SCILAB in simulations and modeling by our chemistry undergraduate students

Face-Dependent Shell-Isolated Nanoparticle Enhanced Raman Spectroscopy of 2,2′-Bipyridine on Au(100) and Au(111)

We have investigated the potential-dependent assembly of 2,2′-bipyridine molecules on both Au(100) and Au(111) surfaces using a newly developed Shell-Isolated Nanoparticle Enhanced-Raman Spectroscopy (SHINERS) technique. We present potential-dependent SHINERS spectra of 2,2′-bipyridine adsorbed on both surfaces collected under anodic as well as cathodic polarization. A series of processes were characterized by the analysis of the data set with Perturbation Correlation Moving Window Two-Dimensional Spectroscopy (PCMW2D) and Two-Dimensional Correlation Spectroscopy (2DCOS). Exquisite spectral detail was achieved and allowed for the characterization of the complicated ring breathing mode and C–C inter-ring stretching modes that are diagnostic of molecular orientation on the surfaces. Detection of several occluded vibration peaks was also made possible with SHINERS. Analysis reveals that in very negative potentials 2,2′-bipyridine adsorbs in a disordered, mixed state with both π-flat cis and several different vertically N-bound cis orientations, in contrast to previously published reports. Our findings provide insight into 2,2′-bipyridine adsorption on Au single crystals and also powerfully combine SHINERS with two-dimensional correlation analysis to yield a more detailed view of spectral transitions