10.1021/jp805620q.s001
Chet Swalina
Chet
Swalina
Sergei Arzhantsev
Sergei
Arzhantsev
Hongping Li
Hongping
Li
Mark Maroncelli
Mark
Maroncelli
Solvation and Solvatochromism in CO<sub>2</sub>-Expanded Liquids. 3. The Dynamics of Nonspecific Preferential Solvation
American Chemical Society
2008
measurement
Molecular dynamics computer simulations
CH 3CN molecules
DCS
measure solvation dynamics
CO
system CH 3CN
cybotactic region
CH 3CN component
GXL
solvatochromism
S 0. Solvation dynamics
2008-11-27 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Solvation_and_Solvatochromism_in_CO_sub_2_sub_Expanded_Liquids_3_The_Dynamics_of_Nonspecific_Preferential_Solvation/2896897
Subpicosecond time-resolved fluorescence of trans-4-dimethylamino-4′-cyanostilbene (DCS) is used to measure solvation dynamics in the gas-expanded liquid (GXL) system CH<sub>3</sub>CN + CO<sub>2</sub> at 25 °C along the liquid−vapor coexistence curve. These measurements are supplemented by measurements of the steady-state solvatochromism of DCS and of its rotation and isomerization times. Molecular dynamics computer simulations and a semiempirical spectral model that reproduces the observed solvatochromism in this system are used to interpret the experimental results. Simulations indicate that at compositions of <i>x</i><sub>CO2</sub> > 0.5, the cybotactic region surrounding DCS is enriched in CH<sub>3</sub>CN molecules, and the extent of this enrichment is greater in S<sub>1</sub> than that in S<sub>0</sub>. Solvation dynamics are dominated by the CH<sub>3</sub>CN component. These dynamics are biphasic, consisting of a subpicosecond inertial component, followed by a slower picosecond component, related to the redistribution of CH<sub>3</sub>CN molecules between the cybotactic region and the bulk solvent.