Susceptibility volume

The magnetic susceptibility of a material (%, volume susceptibility) is dimensionless and is defined as the ratio of induced magnetization to magnetic field intensity. It is expressed as... 

Hence 4 M = -Hj, and the volume susceptibility for a long thin superconducting cylinder with its axis oriented parallel to the applied field is given by ... 

The shielding fraction is a comparison between the measured volume susceptibility and -1/4, and it is given simply by -4 xv... 

Since D is between 0 and 1 in all cases and xv < 0, demagnetization produces an enhanced experimental susceptibility compared to the true volume susceptibility. 

The quantity that is most frequently obtained from experimental measurements of magnetism is the specific (or mass) susceptibility, x- 1 is related to the volume susceptibility through the density, d... 

X, the volume susceptibility , is also a constant, usually of rather small value. It measures how susceptible the substance is to magnetization by the applied field. If x is negative the substance is said to be diamagnetic if positive, paramagnetic or perhaps ferro- or antiferro-magnetic. 

The volume susceptibility of [TCNQ-TTF], %s, thus calculated is then converted to its molar susceptibility, %m, by multiplying the molecular weight of 408 for [TCNQ-TTF] and dividing by the crystal density of 1.6 gm/cc. The results are in excellent agreement. 

Note that the dimensionless magnetic volume susceptibility y is related between the two systems by a factor of 471. 

Magnetic susceptibilities are usually given in the literature on a mass or molar basis. Thus, while the volume susceptibility x is induced moment per unit volume per unit applied field and is dimensionless, the mass susceptibility... 

From the given by this expression and the density of the NiCl2 solution, the volume susceptibility x can be calculated from Eq. (2). With this and the measured weight difference, determine and report the apparatus constant appearing in Eq. (13). 

To obtain the mass susceptibility of the pure paramagnetic material, we assume that the volume susceptibility Xs of th solution can be written as a sum of parts. 

The quantity x is dimensionless (since M and H have the same units) but is usually reported in relation to the sample volume and, hence, is reported as volume susceptibility in cgs units of emu/cm, where emu is an abbreviation for electromagnetic system of units or, in reahty, gauss cm per gram. The corresponding value for the volume suscep-tibUity in SI units is 47t times larger than the value in cgs units. The molar susceptibility, Xm, may be obtained by multiplying x by the molar volume. 

For the definition of AN, see Eq. (2-11). All S values have been extrapolated to zero concentration and corrected for differences in volume susceptibilities. 

Shifts extrapolated to infinite dilution, referred to w-hexane and corrected for the difference in volume susceptibilities between -hexane and the respective solvent. 

The magnetization per unit volume has the same units as the H-field for both cgs and SI units so the volume susceptibility is dimensionless. In practice, it is much more common to work with the molar magnetization Mmoi = My x (MW/p) where MW is the molecular weight and p is the density of the material. 

In comparing the work of Schneider and co workers to that of Huggins, Pimentel, and Shoolery, we should note a different use of reference standards. Schneider and Reeves discuss their use of an external reference sample (1705). In this use, it is generally assumed that the volume susceptibilities of solution components are additive. This assumption is made doubtful by the existence of solvent-solute complex formation. Huggins et al, on the other hand, use an internal reference, i.e., a reference solute dissolved in the solution of interest. Thus a correction for bulk diamagnetic susceptibility is obviated by putting the solute in the same mag netic environment as the species of interest. 

The nitrogen dioxide molecule has 17 valency electrons, and its physical properties are consistent with those expected for an odd-electron molecule. It is paramagnetic, and a volume susceptibility of 3 X c.g.s. unit (39) agrees... 

An alternative method for referencing Li shifts in organolithium compounds has recently been proposed by Jackman et al. [45]. It takes advantage of the multiple frequency probes and radio frequency systems of modem spectrometers and is independent of volume susceptibility difference and the nature of the lock substance. The spectrometer has to be calibrated with, for example, a 0.3 M solution of LiCl in [D]methanol containing 5% TMS. The methanol C signal (secondary reference) is then referenced to the primary standard (TMS) which yields... 

The volume susceptibility of air can often be ignored for solid samples and the mass magnetic susceptibility simplifies to equation (3.4). 

---