Polar and Nonpolar Solvation Dynamics, Ion Diffusion, and Vibrational Relaxation: Role of Biphasic Solvent Response in Chemical Dynamics

Ultrafast solvation response in room temperature ionic liquids: Possible origin and importance of the collective and the nearest neighbour solvent modes

“…5 Moreover, it has been found that solvent dependence of ultrafast solvation dynamics of Ox4 in conventional molecular liquids cannot be described by dielectric relaxation based theories. [6][7][8][9][10] DSS measurements, on the other hand, have employed dipolar chromophores such as coumarin 153 (C153), 3,[11][12][13][14] 4aminophthalimide (4AP), 15 and trans-4-dimethylamino-4 -cyanostilbene (DCS), 2 which undergo large dipole moment changes upon excitation. As a result, Stokes shift values for these probes in phosphonium and imidazolium ionic liquids have been found to be approximately an order of magnitude larger than those with Ox4, and dynamic response explainable by a semi-molecular theory [16][17][18][19][20][21] that uses experimental dielectric relaxation data [22][23][24][25] as inputs.…”

Composition Dependent Stokes Shift Dynamics in Binary Mixtures of 1-Butyl-3-methylimidazolium Tetrafluoroborate with Water and Acetonitrile: Quantitative Comparison between Theory and Complete Measurements

“…To summarize, the present work shows that the semimolecular theory developed earlier 14 4 ] + CH 3 CN) binary mixtures has been reproduced by the present semimolecular theory after incorporating the volume disparity between the IL and the polar solvent molecules constituting the mixture. Two separate modelsone that recognizes the separate identity of the added dipolar solvent molecules and the other that combines the separate dipolar species into one single effective dipolar entityhave been employed and the available experimental ε(ω) 23,46 utilized for calculating both shifts and solvation response functions.…”

“…Note S ss (t) for neat ILs considers 15−22 only 10% contribution from S si (t) which, for these binary mixtures, has become x IL dependent here. Such a small contribution from ion dynamics in our theory 15 4 ] are also presented in each panel to show the effects of polar solvent on IL dynamics. The following aspects are to be noted.…”

“…Comparison between the calculated and measured solvation response functions for C153 in a ([Bmim][BF4 ] + H 2 O) mixture at three representative IL mole fractions. While lines in these panels represent calculations at ∼298 K, the symbols denote (FLUPS + TCSPC) measurements at ∼293 K. Other representations remain the same as inFigure 3.…”

“…The EM calculations are done at 298 K by using experimental ε(ω) for ([Bmim][BF 4 ] + H 2 O) binary mixtures, 23 and the SM predictions by using those for neat [Bmim][BF 4 ] 23 and H 2 O. 64 Calculated and experimental response functions for neat [Bmim][BF4 ] are also shown in these panels to highlight the effects of water on neat IL dynamics. As observed for ([Bmim][BF 4 ] + CH 3 CN) binary mixtures, the EM predictions are slower than both SM predictions and experimental response functions for most of the time except at the late to very late stage of solvation, with the difference being wider at lower x IL .…”