Depolarized Rayleigh scattering and 13C NMR studies of anisotropic molecular reorientation of aromatic compounds in solution

Bauer, David R.; Alms, G. R.; Brauman, John I.; Pecora, R.

doi:10.1063/1.1682300

Cited by 196 publications

(59 citation statements)

References 34 publications

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“…One reason for the discrepancy may be found in our choice of the functional form of the orienting potential as discussed above. On the other hand, it is known that the rotational behaviour of small anisotropic molecules in simple liquids approximates a slipping rather than the sticking boundary condition of classical hydrodynamic theory [20][21][22]. This effect could also explain our results.…”

Section: Discussionsupporting

confidence: 74%

Slow-motion ESR of cholestane spin labels in planar multibilayers of diacyldigalactosyldiglycerides

Dammers

Ginkel

Levine

1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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The orientation and restricted motion of the cholestane spin label (3-spiro-doxyl-5a-cholestane) incorporated into planar muitibilayers of diacyldigalactosyldiglycerides extracted from the thylakoid membranes of chloroplasts from different plant leaves has been studied. The experimental ESR spectra were simulated in terms of the slow-tumbling ESR formalism of Freed and co-workers (Polnaszek, C.F., Bruno, G.V. and Freed, J.H. (1973) J. Chem. Phys. 58, 3185-3199). The analysis shows that the degree of orientational order is low. The spin label molecules undergo a faster reorientational motion about their long molecular axes than perpendicular to them. At room temperature the reorientational rate around the long molecular axis falls within the fast-motionai limit, while the reorientation rate of the long axis itself corresponds to the slow-tumbling regime. The results indicate that the motion of the labels in bilayers of diacyldigalactosyldiglycerides is considerably slower than that of the same label incorporated into bilayers of saturated phosphatidylcholines above the main phase transition. Differences between bilayers of diacyldigalactosyldiglycerides extracted from different plant membranes have been observed.

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Section: Discussionsupporting

confidence: 74%

Slow-motion ESR of cholestane spin labels in planar multibilayers of diacyldigalactosyldiglycerides

Dammers

Ginkel

Levine

1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…This fact indicates that external self-focusing in benzene occurs under nearly steady-state conditions for ruby laser pulses of approximately 30 ps to 40 ps duration. The orientational relaxation time of benzene of r 0^3 .1ps [40][41][42][43][44][45][46][47] (Table 1) is approximately a factor of ten shorter than the pulse duration.…”

Section: Resultsmentioning

confidence: 99%

Determination of nonlinear refractive indices by external self-focusing

Meier

Penzkofer

1989

Appl. Phys. B

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The nonlinear refractive index of benzene is determined by measuring the reduction of the beam divergence of picosecond ruby laser pulses when passing through a benzene sample. Time-integrated spatial beam profiles give an effective refractive index while time-resolved beam profiles measured with a streak camera allow the determination of the temporal evolution of the nonlinear refractive index. PACS:42.65, 42.65.J At high laser powers the refractive index of materials becomes intensity dependent. The spatial laser beam profile causes a spatial refractive index profile and leads to self-focusing [1][2][3][4][5][6]. The overall beam profile is responsible for whole-beam self-focusing while an intensity modulation of the spatial intensity distribution leads to a beam break-up (small-scale selffocusing) [5][6][7][8]. The combined effects of self-focusing and beam diffraction result in filament formation [1][2][3][4][5][9][10][11][12]. The self-focusing increases the pulse intensity enormously and enhances all nonlinear optical effects [13][14][15][16][17][18][19]. The abrupt rise of nonlinear optical effects is an indication of self-focusing and may be used to determine the self-focusing length. The determination of the nonlinear refractive index from the abrupt rise of nonlinear optical effects is complicated by the fact that either whole-scale self-focusing or small-scale selffocusing may act and the small-scale self-focusing parameters (ripple widths and modulation depths) are difficult to determine.The vagueness of whole-scale or small-scale selffocusing dynamics may be avoided by changing from internal self-focusing (focal point caused by nonlinear refractive index is inside sample) to external selffocusing (focal point is outside sample) [1 ]. In this case the nonlinear refractive index of the sample causes a reduction of the overall beam divergence and the effects of small ripples across the beam profile may be neglected.In our experiments we determine the reduction of beam divergence by comparing the beam diameters (FWHM) of two pulses at a certain distance behind the sample position, where one pulse passes through the sample and the other pulse is bypassed. Our timeresolved measurements of the beam diameters with a streak camera and a two dimensional readout system allow the study of the instantaneous and transient contributions to the nonlinear refractive index [12,18,20]. The effective time-averaged and the time-resolved nonlinear refractive index of benzene are measured with picosecond light pulses of a ruby laser. The reported time-averaged nonlinear refractive index coefficients n 2 of benzene vary by a factor of ten in the region between n 2 = 1.4x 10~2 1 m 2 V~2 and lxlO" 20 m 2 V-2

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“…The computed values of D s were corrected for system size effects using the hydrodynamic model of Yeh and Hummer 78 of a particle surrounded by a solvent with a viscosity, η, (4) Isothermal compressibilities were calculated from (5) where V is the volume, 〈δV 2 〉 are volume fluctuations and K B is the Boltzmann's constant.…”

Section: Methodsmentioning

confidence: 99%

Polarizable Empirical Force Field for Aromatic Compounds Based on the Classical Drude Oscillator

et al. 2007

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The polarizable empirical CHARMM force field based on the classical Drude oscillator has been extended to the aromatic compounds benzene and toluene. Parameters were optimized for benzene and then transferred directly to toluene, with parameters for the methyl moiety of toluene taken from the previously published work on the alkanes. Optimization of all parameters was performed against an extensive set of quantum mechanical and experimental data. Ab initio data was used for determination of the electrostatic parameters, the vibrational analysis, and in the optimization of the relative magnitudes of the Lennard-Jones parameters. The absolute values of the Lennard-Jones parameters were determined by comparing computed and experimental heats of vaporization, molecular volumes, free energies of hydration and dielectric constants. The newly developed parameter set was extensively tested against additional experimental data such as vibrational spectra in the condensed phase, diffusion constants, heat capacities at constant pressure and isothermal compressibilities including data as a function of temperature. Moreover, the structure of liquid benzene, liquid toluene and of solutions of each in water were studied. In the case of benzene, the computed and experimental total distribution function were compared, with the developed model shown to be in excellent agreement with experiment.

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Depolarized Rayleigh scattering and 13C NMR studies of anisotropic molecular reorientation of aromatic compounds in solution

Cited by 196 publications

References 34 publications

Slow-motion ESR of cholestane spin labels in planar multibilayers of diacyldigalactosyldiglycerides

Slow-motion ESR of cholestane spin labels in planar multibilayers of diacyldigalactosyldiglycerides

Determination of nonlinear refractive indices by external self-focusing

Polarizable Empirical Force Field for Aromatic Compounds Based on the Classical Drude Oscillator

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