ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubpicosecond Measurements of Polar Solvation Dynamics: Coumarin 153 RevisitedM. L. Horng, J. A. Gardecki, Papazyan, and M. MaroncelliCite this: Phys. Chem. 1995, 99, 48, 17311–17337Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue 1 November 1995https://pubs.acs.org/doi/10.1021/j100048a004https://doi.org/10.1021/j100048a004research-articleACS PublicationsRequest reuse permissionsArticle...

Solvation dynamics in polar liquids have been examined using the probe molecule coumarin 153 (Cu153) and picosecond spectroscopic techniques. Steady-state absorption fluorescence spectra of Cu153 as a function solvent show that frequency electronic spectrum this provides convenient measure solvation energetics. Both nonspecific dipolar to smaller degree H-bonding solute–solvent interactions are involved. Time-correlated single photon counting was used observe time-dependent shifts variety...

Two of the more fundamental ways in which molecules change their behavior when they are dissolved that can begin to exchange energy with surrounding liquid and induce surroundings rearrange so as provide a significant stabilizing influence. The first these is typified by process vibrational population relaxation vibrationally hot species. second conceptcritical solution chemistryis what known solvation. Both processes sufficiently one would really like know, at most mechanical molecular...

Polar solvents often exert a dramatic influence on reactions in solution. Equilibrium aspects of this involve differential solvation reactants compared to the transition state that lead alteration free-energy barrier reaction. Such effects are well known, and give rise changes reaction rates many orders magnitude. Less understood arising from non-equilibrium, dynamical solvation. During course reaction, charge is rapidly redistributed among reactants. How couples its solvent environment...

Equilibrium and nonequilibrium molecular dynamics computer simulations have been used to study the time dependence of solvation in water. The systems investigated consisted monatomic ions immersed large spherical clusters ST2 Relaxation energy following step junction jumps solute’s charge, dipole moment, quadrupole moment determined from equilibrium (MD) under assumption a linear response. relaxation times observed differ substantially depending on type multipole jump charge/size ratio...

Steady-state and time-resolved emission measurements of the solvatochromic probe coumarin 153 are used to study solvation a dipolar solute in nondipolar solvents such as benzene 1,4-dioxane. Contrary predictions dielectric continuum theories, Stokes shifts (or nuclear reorganization energies) that accompany electronic excitation this substantial (∼1000 cm-1). The magnitudes observed both can be consistently understood terms relative strength interactions between permanent charge...

Computer simulations of the solvation monatomic ions in acetonitrile are used to investigate dynamical aspects polar aprotic solvents. The observed dynamics depend significantly on solute charge and which multipole moment is perturbed. In all cases, response has a two-part character. One part consists fast initial relaxation attendant oscillations, both occur time scale 0.1–0.2 ps. well fit by Gaussian function accounts for ∼80% total relaxation. second component occurs much slower, ∼1 ps...

Physical properties of 4 room-temperature ionic liquids consisting the 1-butyl-3-methylimidazolium cation with various perfluorinated anions and bis(trifluoromethylsulfonyl)imide (Tf2N-) anion 12 pyrrolidinium-, ammonium-, hydroxyl-containing cations are reported. Electronic structure methods used to calculate related size, shape, dipole moment individual ions. Experimental measurements phase-transition temperatures, densities, refractive indices, surface tensions, solvatochromic polarities...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNonplanar conformers and the phase behavior of solid n-alkanesMark Maroncelli, Song Ping Qi, Herbert L. Strauss, Robert G. SnyderCite this: J. Am. Chem. Soc. 1982, 104, 23, 6237–6247Publication Date (Print):November 1, 1982Publication History Published online1 May 2002Published inissue 1 November 1982https://pubs.acs.org/doi/10.1021/ja00387a013https://doi.org/10.1021/ja00387a013research-articleACS PublicationsRequest reuse permissionsArticle...

Subpicosecond resolution measurements of the kinetics dipolar solvation have been made. The time resolved Stokes shift a dye molecule, LDS-750 was measured using fluorescence upconversion technique in solvents acetonitrile, DMSO, nitrobenzene, methanol, and n-butanol. dynamics both aprotic alcohol occur on scale roughly given by longitudinal relaxation as predicted simple continuum theories. nitrobenzene butanol is nonexponential methanol significantly faster than calculated time. These...

Ionic liquids are subjects of intense current interest within the physical chemistry community. A great deal progress has been made in just past five years toward identifying factors that cause these salts to have low melting points and other useful properties. Supramolecular structure organization emerged as important complicated topics may be key understanding how chemical reactions processes affected by ionic liquids. New questions posed, an active debate is ongoing regarding nature...

Steady-state and time-resolved emission spectroscopy with 25 ps resolution are used to measure equilibrium dynamic aspects of the solvation coumarin 153 (C153) in a diverse collection 21 room-temperature ionic liquids. The liquids studied here include several phosphonium imidazolium previously reported as well 12 new that incorporate two homologous series ammonium pyrrolidinium cations. absorption spectra extract free energies reorganization associated S0 ↔ S1 transition C153. These...

Subpicosecond fluorescence anisotropy measurements are used to characterize the rotational dynamics of coumarin 153 (C153) in 35 common solvents and eight solvent mixtures at room temperature. The decays C153 generally nonexponential as a result non-Markovian nature friction on its motion. Rotational correlation times observed be larger polar than nonpolar same viscosity. This difference is examined context theories dielectric friction, which relate extra solute/solvent systems long-range...

Steady-state spectra, rotation times, and time-resolved emission spectra of the probe 4-aminophthalimide (4-AP) in ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim+][PF6-]) were measured over temperature range 298−355 K. The steady-state spectroscopy indicates that solvation energetics 4-AP [bmim+][PF6-] are comparable to those highly polar but aprotic solvents such as dimethylformamide acetonitrile (π* ∼ 0.8, 0.4). more conventional generally conforms expectations...

This paper describes results of simulations solvation dynamics a variety solutes in two reference solvents, acetonitrile and methanol. Part these studies involve attempts to realistically model the observed experimentally with fluorescence probe coumarin 153 (C153). After showing that linear response afford reliable route interest, experimental simulation for C153 are compared. Agreement between calculated is found be satisfactory case but poor The latter failure traced lack realism...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA simple interpretation of polar solvation dynamicsM. Maroncelli, Vijaya P. Kumar, and Arno PapazyanCite this: J. Phys. Chem. 1993, 97, 1, 13–17Publication Date (Print):January 1993Publication History Published online1 May 2002Published inissue 1 January 1993https://pubs.acs.org/doi/10.1021/j100103a004https://doi.org/10.1021/j100103a004research-articleACS PublicationsRequest reuse permissionsArticle Views416Altmetric-Citations231LEARN ABOUT THESE...

Solvation and rotational dynamics of coumarin 153 (C153) were measured in a series phosphonium ionic liquids consisting the trihexyl(tetradecyl)phosphonium cation anions Br-, Cl-, dicyanamide-, bis(trifluoromethylsulfonyl)imide-, BF4-. None these display prominent ultrafast solvation component comparable to one observed imidizalium liquids. The on nanosecond time scale are also 5-fold slower than those imidazolium viscosities. Both rotation highly nonexponential functions can be represented...

Dynamic Stokes shift measurements of the solvatochromic probe trans-4-dimethylamino-4'-cyanostilbene were used to measure solvation response five imidazolium and one pyrrolidinium ionic liquid at 25 °C. The Kerr-gated emission time-correlated single-photon-counting techniques spectral dynamics occurring over time ranges 100 fs−200 ps 50 ps−5 ns, respectively, a combination data sets from these two enabled observation complete response. Observed functions found be biphasic, consisting...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTemperature and phase behavior of infrared intensities: the poly(methylene) chainR. G. Snyder, M. Maroncelli, H. L. Strauss, V. HallmarkCite this: J. Phys. Chem. 1986, 90, 22, 5623–5630Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/j100280a030https://doi.org/10.1021/j100280a030research-articleACS PublicationsRequest reuse permissionsArticle...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFluorescence studies of solvation and dynamics in ionic solutionsCurtis F. Chapman Mark MaroncelliCite this: J. Phys. Chem. 1991, 95, 23, 9095–9114Publication Date (Print):November 1, 1991Publication History Published online1 May 2002Published inissue 1 November 1991https://pubs.acs.org/doi/10.1021/j100176a016https://doi.org/10.1021/j100176a016research-articleACS PublicationsRequest reuse permissionsArticle Views604Altmetric-Citations190LEARN ABOUT...

The distributions of conformational defects that exist in the high-temperature phase II (also referred to as hexagonal or rotator phase) crystalline n-alkanes C21 and C29 have been measured by an infrared CD2-substitution technique accounted for terms a lattice model provides freedom longitudinal displacement chains. consist almost entirely gtg′ kinks distributed nonuniformly along chain. uneven distribution is indicated variation concentration gauche bonds at various sites highest chain...