Showing papers by "Peter J. Rossky published in 1990"
TL;DR: In this article, the authors focus on the decomposition of the equilibrium optical spectrum into the underlying electronic excitations and on simulation of a proposed photophysical hole-burning experiment designed to test the veracity of this decomposition.
Abstract: The rapidly advancing area of computer simulation for quantum-mechanical systems now permits the direct evaluation of spectroscopic observables for condensed phase systems, which increasingly overlaps frontier ultra-fast measurements. In this paper recent theoretical techniques are outlined and representative results from application to the hydrated electron are described that exemplify the close connection between theory and experiment that can now be made. Results focus, first, on the decomposition of the equilibrium optical spectrum into the underlying electronic excitations and on simulation of a proposed photophysical hole-burning experiment designed to test the veracity of this decomposition. Second, the author examines aspects of the transient relaxation of initially nonequilibrium photogenerated electrons by simulation of the spectroscopic signature of proposed early time states and of the relaxation of these states to equilibrium.
21 citations
01 Jan 1990
TL;DR: In this article, the authors discuss the nature of the distribution of small ions around polyelectrolytes and examine the sensitivity of the distributions to salt concentration and polyion charge density, showing that the ionic environment around highly charged polyions is relatively insensitive to large changes in bulk electrolyte concentrations.
Abstract: Association between electrolyte ions and polyions is of fundamental importance. Here, we discuss the nature of the distribution of small ions around polyelectrolytes and examine the sensitivity of the distribution to salt concentration and polyion charge density. Two polyion models are considered, namely, a simplified one in which the polyion is taken to be a uniformly charged cylinder and an atomically more detailed one in which the smaller ions interact with the polyion on an atom by atom basis. The hypernetted chain integral equation and Monte Carlo computer experiments are used to develop the results for ionic distributions. The results confirm that the ionic environment around highly charged polyions is relatively insensitive to large changes in bulk electrolyte concentrations in the case of the simpler model of the polyion. Further, the concept of an effective net charge for the polyion as a determinant for the asymptotic electrostatic potential holds. The results for the more detailed model of the polyion indicate that charge association can be understood qualitatively using the simpler, uniformly charged model. Such a simplification is, however, not sufficient for determining the local ionic concentrations and the spatial extent of the association quantitatively.