Kerr effect measurements

SLS, birefringence, dielectric constant Kerr effect) measurements... 

A combination of molecular mechanics calculations and electric birefringence (electro-optical Kerr effect) measurements of group IVB aryl compounds has been used to study conformational effects in these molecules12731. 

Palese S, Mukamel S, Miller RJD, Lotshaw WT. Interrogation of vibrational structure and line broadening of liquid water by Raman-induced Kerr effect measurements within the multi-mode Brownian oscillator model. I Phys Chem 1996 100 10380-10388. 

Neelakandan M, Pant D, Quitevis EL. Structure and intermolecular dynamics of liquids femtosecond optical Kerr effect measurements in nonpolar fluorinated benzenes. J Phys Chem A 1997 101 2936-2945. 

Neelakandan M, Pant D, Quitevis EF. Reorientational and intermolecular dynamics in binary liquid mixtures of hexafluorobenzene and benzene femtosecond optical Kerr effect measurements. Chem Phys Fett 1997 265 283-292. 

Since, in the Kerr effect measurements, light, acting solely as an analysing agent, is of low intensity and thus gives rise to linear polarization only, we write ... 

In the expressions (184) and (184b) the second, temperature-dependent term defines the Born effect due to superposition of the two non-linear processes of second-order distortion and reorientation of permanent dipole moments in the electric field. Buckingham et al. determined nonlinear polarizabflities If and c for numerous molecules by Kerr effect measurements in gases as a function of temperature and pressure. It is here convenient to use the virial expansion of the molar Kerr constant, when the first and second virial coefficients Ak and Bk result immediately from equations (177), (178), and (184). Meeten et al. determined nonlinear molecular polarizabilities by measuring K in liquids as a function of temperature. 

We have performed optically heterodyne-detected optical Kerr effect measurement for transparent liquids with ultrashort light pulses. In addition, the depolarized low-frequency light scattering measurement has been performed by means of a double monochromator and a high-resolution Sandercock-type tandem Fabry-Perot interferometer. The frequency response functions obtained from the both data have been directly compared. They agree perfectly for a wide frequency range. This result is the first experimental evidence for the equivalence between the time- and frequency-domain measurements. 

In this paper we review the linear and nonlinear optical properties studies performed on solutions or thin film of rotaxanes and catenanes. Tlte linear optical properties were studied by U V-Vis spectrometry and m-line techniques. Tlte nonlinear optical properties were studied by second (SHG) and third (THG) harmonic generation in thin films and by electro-optic Kerr effect measurements in solutions. 

Figure 28. Schematic representation of the experimentai set up for electro-optic Kerr effect measurements. The normal to the sample is tilted by 45 degrees with respect to the beam propagation direction and the incident polarization makes an angle of 45° with incidence plane...

Comparable behavior has been observed by Payer et al. in a series of subpicosecond transient grating optical Kerr effect measurements on the reorientation of byphenyl molecules in neat biphenyl and n-heptane solutions [66,67]. They have shown that on the ultrafast timescale (r < 2 ps) the dynamics of the probe is controlled by librational motions having an inertial character, although diffusive reorientational relaxation of the whole molecule and internal torsional motions can also have a role. 

Meier, W. (1997) Kerr effect measurements on a poly(oxyethylene) containing water-in-oil microemulsion. /. Phys. Chem. B, 101, 919-921. 

Fig. 8. (Top) Energy dependence of the polar Kerr rotation

Dipole moment and Kerr effect measurements are frequently used for conformational analyses, e,g., the recent studies of the phosphepanes (88) and 1,3,2,5-dioxasilaphosphorinanes (89). On the other hand the anisotropy of polarization and conformational analysis of triphenylphosphine, trimesityl-phosphine, and their chalcogenides also incorporated Raleigh scattering measurements (c/. ref. 236), whilst conformation studies of 1,3,5-dioxaphosphorinanes combined dipole moments with n.m.r. or u.v. data or reactive field calculations. ... 

Feierabend et al. (1976) have shown the pressure effect by magnetization and Kerr effect measurements versus the temperature. With e-gun evaporation onto a cold substrate (12 K), in a vacuum of 10 Torr, the Curie temperature is 26.5 K. But in a vacuum of 10" Torr it is larger and decreases after annealing. These variations indicate that contaminations were present in the film. 

BUS] Arc melting, XRD, magnetic, Kerr effect measurements 800°C, Mo2Fe2iC6... 

Erskine and Stern (1973) reported the most careful Kerr effect measurement for Gd. The samples were films deposited in vacuum and measured in situ. They are magnetized in the plane of the films. The rotation of the polarization axis and the ellipticity were measured, and from these quantities the off-diagonal conductivity tensor was deduced. The results for the real and imaginary parts of a-, at 105 K are shown in fig, 3.43. Comparing the imaginary part with the joint density of states curve for Gd in fig. 3.43, we find that the peak at 2 eV in the... 

Transient Kerr effect measurements have been used primarily to study large molecules (polymers and biopolymers) or smaller molecules at sufficiently low temperatures as discussed by G. Williams. The limitations are because the relaxation time scale must not be shorter than the time resolutions for available transient field generators and optical detectors. Wntil recently this has set short time limits of 10 ° to 10 seconds at best. These are too large for useful studies of small molecules in liquids at ordinary temperatures but developments in pump and probe laser tectmiques have already made some measurements possible with picosecond resolution (as discussed by Kenney-Wallace In this volume) and it should be possible to do much more with availability of fast solid state switching and optical coupling devices. 

One can hope that these will not greatly affect comparisons of macroscopic relaxation functions rather than microscopic functions and that better treatments as from Fulton s methods for example will clarify these questions. Even so, It seems fair to claim that a better basis now exists for extracting useful information from Kerr effect measurements and to explore questions of whether rotational reorientations in time are diffusion or Brownian motion like at one extreme infrequently by large jumps at the other or something in between. With developments in instrumentation of the sort suggested above there appear to be real possibilities for studies of dynamics of simpler molecules to complement those by other methods. 

Hyun, B. -R., Dzyuba, S. V., Bartsch, R. A., and Quitevis, E. L. 2002. Intermolecu-lar dynamics of room-temperature ionic liquids Femtosecond optical Kerr effect measurements on l-alkyl-3-methylimidazolium bis( (trifluoromethyl)sulfonyl) imides. J. Phys. Chem. A 106, 7579-7585. 

Figure 6 Observed dipolar absorption spectra obtained by the THz technique of liquid benzene (circles), 1,3,5-trifluorobenzene (triangles), and hexafluorobenzene (cubes). OHD-RIKES spectra (broken lines) and the OHD-RIKES spectra in the R v) representation (full lines) [Eq. (1)] (see text). [The THz results for 1,3,5-trifluorobenzene, and hexafluorobenzene are reproduced with permission from SR Keiding. THz-Pulses. D.Sc. thesis. University of Aarhus, Denmark, 1998 THz data for benzene are shown with permission from C Rpnne, K Jensby, SR Keiding prior to publication. The OHD-RIKES data are from M Neelakandan, D Pant, EL Quitevis. Structure and inter-molecular dynamics of liquids Femtosecond optical Kerr effect measurements in nonpolar fluori-nated benzenes, J Phys Chem A 101 2943, 1997. Reproduced with permission from the American Chemical Society.]...

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