Molecular Dynamics Simulations of Solvation and Solvent Reorganization Dynamics in CO2-Expanded Methanol and Acetone.

Composition-dependent solvation dynamics around the probe coumarin 153 (C153) have been explored in CO2-expanded methanol and acetone with molecular dynamics (MD) simulations. Solvent response functions are biexponential with two distinct decay time scales: a rapid initial decay (∼0.1 ps) and a long relaxation process.

Effects of solute structure on local solvation and solvent interactions: results from UV/vis spectroscopy and molecular dynamics simulations.

Solvation of heterocyclic amines in CO(2)-expanded methanol (MeOH) has been explored with UV/vis spectroscopy and molecular dynamics (MD) simulations. A synergistic study of experiments and simulations allows exploration of solute and solvent effects on solvation and the molecular interactions that affect absorption. MeOH-nitrogen hydrogen bonds hinder the n-pi* transition; however, CO(2) addition causes a blue shift relative to MeOH because of Lewis acid/base interactions with nitrogen.

A spectroscopic and computational exploration of the cybotactic region of gas-expanded liquids: methanol and acetone.

Local compositions in supercritical and near-critial fluids may differ substantially from bulk compositions, and such differences have important effects on spectroscopic observations, phase equilibria, and chemical kinetics. Here, we compare such determinations around a solute probe dissolved in CO2-expanded methanol and acetone at 25 degrees C from solvatochromic experiments with molecular dynamics simulations. UV/vis and steady-state fluorescence measurements of the dye Coumarin 153 in the expanded liquid phase indicate preferential solvation in both the S0 and S1 states by the organic species.