Rotational relaxation of ocs in liquid n-alkanes

Goulay-Bize, A.M; Dervil, E.; Vincent‐Geisse, J.

doi:10.1016/0009-2614(80)85071-8

Cited by 17 publications

(7 citation statements)

References 18 publications

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“…As previously noted, such size effects are not unique to C153. Similar effects have been observed in a number contexts previously, mainly with nonpolar solutes, ,,,− and it seems likely that this size dependence is a general phenomenon. Some indication of this generality is provided by the comparison (Figure ) between the data collected here on C153 and data compiled on the rotation times of 16 assorted solutes in the single solvent n -hexane …”

Section: Discussionsupporting

confidence: 87%

“…Attempts to fit the lower viscosity data (η ≤ 3 cP) to a linear function of viscosity yield unrealistically large η = 0 intercepts (〈τ〉 rot = 11.2 + 23.2η; N = 11, R = 0.97). Similar power-law behavior has been observed in a number of other cases previously. , As we will discuss shortly, this deviation from hydrodynamic behavior is probably best understood in terms of the presence of some factor in addition to solvent viscosity that makes the solvent−solute coupling ( C ) vary with solvent.…”

Section: Resultssupporting

confidence: 80%

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Rotational Dynamics of Coumarin 153: Time-Dependent Friction, Dielectric Friction, and Other Nonhydrodynamic Effects

1997

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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 rotational anisotropy decays of C153 are generally nonexponential as a result of the non-Markovian nature of the friction on its rotational motion. Rotational correlation times are observed to be larger in polar solvents than in nonpolar solvents of the same viscosity. This difference is examined in the context of theories of dielectric friction, which relate the extra friction in polar solute/solvent systems to long-range dipole−dipole interactions. Since the latter interactions have been thoroughly characterized via dynamic Stokes shift measurements for the same solute/solvent combinations studied here, the present data provide a unique opportunity to test general concepts of dielectric friction. Contrary to expectations, the departures from simple hydrodynamic behavior cannot be modeled using only theories of rotational dielectric friction. More important than dielectric friction is the role that the relative solute/solvent size plays in determining the extent of solute−solvent coupling. Once this size dependence is approximately accounted for, the remaining departures from simple hydrodynamic behavior are relatively small in all solvents. In polar aprotic solvents, solvation data indicate that dielectric friction effects should be rather modest (10−20% of the total friction). In these solvents no clear correlation is found between dielectric friction predictions and the observed solute−solvent coupling. However, in normal alcohol solvents the effects of dielectric friction are predicted to be large and well beyond the scatter in the experimental data. No evidence for such an important dielectric friction contribution is observed in these solvents, in spite of the fact that long-time components of the solvation dynamics do appear to be present in the rotational friction.

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Section: Discussionsupporting

confidence: 87%

Section: Resultssupporting

confidence: 80%

Rotational Dynamics of Coumarin 153: Time-Dependent Friction, Dielectric Friction, and Other Nonhydrodynamic Effects

1997

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“…Taking the natural log of Eq. (12) one obtains (13) Therefore a plot of In (172/1/1) vs In (P) -ap is predicted to be linear.…”

Section: T8'mentioning

confidence: 96%

Reorientational motion, collision-induced scattering, and vibrational relaxation in liquid carbonyl sulfide

Hegemann

Jonáš

1983

The Journal of Chemical Physics

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Articles you may be interested inThe effects of vibrational mode and collision energy on the reaction of formaldehyde cation with carbonyl sulfide Dynamics of molecular reorientational motion and vibrational relaxation in liquids. ChloroformThe rotational and vibrational behavior of neat liquid carbonyl sulfide under its own vapor pressure is investigated through Raman line shape studies of the symmetric v I C = S stretching mode over the temperature range T = 183 to 303 K. The reorientational motion is found to be near the diffusional limit. Various methods of determining the reorientational correlation time 'To are compared and their validity discussed. The contribution of collision-induced scattering to the v I mode rotational line shape is examined semiquantitatively. It is found that the relative contribution of collision-induced scattering to the overall rotational line shape increases with increasing temperature and decreasing density, whereas the second moment of the collision-induced line shape decreases. Assuming the separability of the collision-induced scattering contribution and the reorientational contribution to the observed line shape, the experimental data are discussed qualitatively in terms of the dipole-induced-dipole (DID) theory of Balucani and Vallauri. The vibrational relaxation mechanism for the v I mode is attributed to dephasing and interpreted by Kubo line shape theory. The dephasing is found to be in the "motionally narrowed" regime and discussed qualitatively in terms of attractive dipolar forces.

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“…Consequently, we shall not interpret the result for neon in figure 6 and, in disregarding it, conclude that 8 is dependent, in all other cases, on the active molecule only. The full lines in figure 6, which relate to the perturbing gases, show that, for a given value of (<C2>/P)exp, 8 increases from krypton to neon, i.e. with decreasing size of the perturbing gas.…”

Section: V(ro)=ge[(r)'2--(r)61+4e(3cos20--m[½6 /~\'2mentioning

confidence: 97%

“…Figure 4 shows infrared spectra of CO2 perturbed by 468 amagat of krypton and dissolved in liquid pentane [8].…”

Section: Case O[ Co~-kr At Higher Pressure (Up To 650 Bar)mentioning

confidence: 99%

Mean square torque from linear molecule-rare gas atom systems at intermediate pressures

Berreby

Dayan

1983

Molecular Physics

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From spectral moments of infrared vibration-rotation bands, the mean square torques are measured for COg, N20 and C2D 2 mixed with neon, argon and krypton and appear to be a linear function of the density up to 250 amagat. Above this density and up to 468 amagat, a departure from linearity is observed in the study of CO2-krypton mixtures.In the linear range, a Semi-empirical interrnolecular potential, proposed by Gordon, is used to interpret the results. This potential introduces an anisotropic parameter ~ for the repulsive forces. It is shown that ~ is dependent only on the active molecule. Moreover, it is concluded that the repulsive forces play a dominant part in the mean square torque.

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Rotational relaxation of ocs in liquid n-alkanes

Cited by 17 publications

References 18 publications

Rotational Dynamics of Coumarin 153: Time-Dependent Friction, Dielectric Friction, and Other Nonhydrodynamic Effects

Rotational Dynamics of Coumarin 153: Time-Dependent Friction, Dielectric Friction, and Other Nonhydrodynamic Effects

Reorientational motion, collision-induced scattering, and vibrational relaxation in liquid carbonyl sulfide

Mean square torque from linear molecule-rare gas atom systems at intermediate pressures

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