Magnetic susceptibility samples

Gouy balance A balance for the determination of magnetic susceptibility. The sample is weighed in and out of a magnetic field and the susceptibility is calculated from the difference in weights. 

Other magnetic measurements of catalysts include electron paramagnetic resonance and magnetic susceptibility. Although those are not as common as NMR, they can be used to look at the properties of paramagnetic and ferromagnetic samples. Examples of these applications can be found in the literature [87. 

The formation and presence of both phases of the Pd-H system in the palladium catalyst samples investigated was confirmed by Brill and Watson by the values of the magnetic susceptibility of the samples investigated under the same conditions as in the kinetic studies. 

The direct proof of hydride formation in situ in a reaction vessel is in principle possible. One can follow changes of resistance (of a film, a wire, etc.) or of magnetic susceptibility of a catalyst. Hydride identification by means of the X-ray diffraction method requires a catalyst sample to be taken out from a reaction vessel, and eventually frozen in order to avoid a rapid decomposition of the hydride under ambient conditions (67). 

Measurements. Infra-red spectra for the region 600-4000 cm-1 were measured with a Perkin-Elmer Model 710B spectrometer on samples pressed in KBr pellets. Magnetic susceptibilities were measured with a vibrating sample magnetometer (Princeton Applied Physics) as previously described.(4)... 

Rather than quote some (mass normalized) force on the sample at each of several field strengths, it is sufficient to report the slope of the linear part of the curve in Fig. 5-6. This slope is called the magnetic susceptibility of the sample. Units for susceptibility, x > and related quantities to be discussed in this section are reviewed in Box 5-3. 

There will exist an equilibrium between the two states. If the ener between the two states, E, is of the order of kT, then the relative populations of the two states will vary with the temperature of the sample. In the Fe(III) dithiocarbamate series of complexes, [FeCRiRgdtcla], AE can be varied by suitable choice of substituents Ri and Rj. Although these are well removed from the FeSg molecular core, they can appreciably affect the electronic parameters of the central iron atom and of the surrounding crystal field of the sulfur atom by way of the conjugated system of the ligand (237). The results of the spin crossover are reflected in magnetic susceptibility data. 

Magnetic-susceptibility measurements showed the presence of UF4 in heated samples. Ebert et al. (E14) reported a nominal stoichiometry CisUFg, magnetic-susceptibility measurements indicating partial reduction at room temperature, with 10% of the uranium species present as U(IV). Wide-line NMR demonstrated the presence of both U(VI) and U(IV). 

The significant improvements in sensitivity achieved during the last 5 years have been because of improved probe design and radiofrequency circuits. Since the probe needs to be located very close to the sample, it must be made of a material with a low magnetic susceptibility, for otherwise it would cause distortions of the static magnetic field thereby adversely affecting line shape and resolution. Much research has therefore been undertaken by NMR spectrometer manufacturers to develop materials that... 

Size of sample 2 was determined using magnetic susceptibility, as described below. 

Table I. Samples Used for MOssbauer Spectroscopy and Magnetic Susceptibility Studies...

Fe(6-Mepy)2(py)tren] (004)2 Doped in PSS. Magnetic susceptibilities measured for a microcrystalline sample of the complex produce a magnetic moment value = 0.36 pg at 10 K and 0.61 pg at 150 K, followed by a gradual increase to Peff = 2.80 pe at 311 K [138]. Thus 26% of the complexes are in the HS state at 300 K if a magnetic moment of 5.1 Pe is assumed for the pure HS compound. On the other hand, the complex doped into a polystyrene sulfonate (PSS) film does not provide any evidence for a thermal population of the HS state up to 340 K as demonstrated by variable-temperature UV-VIS and Mossbauer spectra. In fact, all the complexes doped into the PSS film are in the LS state at temperatures below 340 K. However, if irradiated by a single pulse of a Q-switched Nd/YAG laser (532 mp), the complex is excited from the LS ground state to the HS J2 states via an intermediate MLCT state and the metal states. The subsequent back relaxation from the excited T2 state to the... 

Figure 1.160. Magnetic susceptibility value of studied rock samples. Most younger two samples (NK-12 and -13) of Nishikurosawa shale have anomalously high magnetic susceptibility value.

A recent report of Hill et al. (192) states that the low values of the magnetic susceptibility of Mn(Et2rftc)2 obtained by Lahiry and Anand are due to partial oxidation of the sample and that the compound has a sextet ground state. The dimeric [Mn(Et2C tc)2]2 is not X-ray isomorphous with Ni(Et2< tc)2, but gives a powder pattern similar to, though not identical with Cu(Et2[Pg.95]

Figure 5.8 Static magnetic data for the Er(trensal) complex in the case of a powdered sample and an oriented single crystal measured in parallel or perpendicular direction to the C3 rotation axis, (a) Temperature dependence of the magnetic susceptibility...

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