Magnetic susceptibility calculations

Sharp line luminescence has also been observed for [OsBr6]2- doped in crystals of Cs[ZrBr6] at 20 K.103 The magnetic susceptibility calculated from optical data agrees well with available susceptibility data for Cs2[OsBr6]. 

Since these local group susceptibility values are derived under the explicit assumption that all electron motions are localized, the difference between the observed magnetic susceptibility and that calculated from local group values should provide a quantitative measure of electron delocalization and perhaps aromaticity.19 There are also a variety of other applications for the local susceptibilities given in Table 8. For instance, molecular values can be measured in a number of small molecules by molecular beam techniques.1 In many of these molecules an accurate measurement of the susceptibility anisotropy is difficult. Magnetic susceptibilities calculated by the methods of this paper can thus be combined with g values obtained by other methods to extract quad-rupole moments. Alternatively, calculated susceptibility anisotropies... 

Table 13.2 Magnetic susceptibilities anisotropies of magnetic susceptibilities A/ (10 mol ), magnetic susceptibilities calculated from local increments and magnetic...

Fig. 112. (NH4)2MnF5 sc. (a) Temperature dependence of Xm in the three crystallographic axes. y. is divergent at 0(1=7.5 K. (b) Magnetic susceptibility calculated from model of classical spins in an axial crystalline field using J/k=12.2 K and 0=3.31 K. The dotted line shows the off diagonal sublattice susceptibility y which does not appear in the bulk measurement [73K12]. ...

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. 

Figure A2.3.29 Calculation of the critical temperature and the critical exponent y for the magnetic susceptibility of Ising lattices in different dimensions from high-temperature expansions.

In the light of these results, it is not surprising that a very large anisotropy has been calculated [24] to exist in the magnetic susceptibility of nanotubes. The susceptibility with the field parallel to the tube axis is predicted to be as much as 3 orders of magnitude smaller than that with the field perpendicular. Again,... 

The magnetic susceptibility of Na[Pu02(CH3COO)3] was measured by Dawson between 90 and 333 K (3). The resulting magnetic moment, yjff = 8.0 Ug, is temperature independent and corresponds to = 8.70 Ug, which is calculated from EPR measurements on a... 

With respect to the physical properties mentioned, band-structure calculations have attracted considerable interest, e.g., for SbSBr, SbSI, and SbSel (234). For the compounds having reference 22i in column 4 of Table XXIX, a temperature-independent diamagnetism has been found, with values of about 10 cm" g between 77 and 340 K. A small temperature-dependence is exhibited by BiTel, a narrow-gap semiconductor (41). The anisotropy of the magnetic susceptibility has been studied for SbSI, BiSel, and BiTel (41, 420). 

Like TME, the diradical 15 was shown to have nearly degenerate singlet and triplet states by magnetic susceptibility [60, 61], although the early works by Dowd identified a triplet ground state on the basis of ESR spectrum [62, 63], The UCCSD(T) calculations predicted a singlet ground state with a small S-T gap of... 

The anisotropy of the magnetic susceptibility of a cyclic conjugated system, attributable to induced ring currents in its rc-electron network, is one of the important quantities indicative of 7t-electron delocalization. The method used for the calculation of the magnetic susceptibilities of nonalternant hydrocarbons is the London-Hoarau method taken together with the Wheland-Mann SCF technique . The resonance integral is assumed again to be of exponential form but... 

Table 4. Calculated magnetic susceptibilities (AK) and experimental exaltation (A)...

Microwave spectra obtained from PHgD and PHDa in a magnetic field of about 25 kG showed Zeeman effects, from which molecular g values were calculated. They were 20 times smaller than those for ammonia. The molecular quadrupole moments of phosphine and ammonia were approximately the same. Magnetic susceptibilities and molecular quadrupole moments were also compared. 

We carried out a second calculation for BeH at an internuclear distance of 2.67 a.u. corresponding to the minimum of energy.The mean magnetic susceptibility x obtained value, which is equal to -0,86.lO erg.G. mol V, agrees more closely to the value calculated by Fowler and Steiner [5], at the same internuclear distance,which is equal to -0.50 10 erg. G. mol F... 

In Table 5, we show the calculated magnetic susceptibilities for AlH and SiH+, and the Lipseomb et al. [7] obtained values for AlH using an extended basis set of field independent Slater type orbitals. 

Four-coordinate, planar iron(II)-dithiolate complexes also exhibit intermediate spin. The first example described was the tetraphenylarsonium salt of the square-planar bis(benzene-l,2-dithiolate)iron(II) dianion, (AsPh4)2[Fe(II)bdt2], which showed 5 = 0.44 mm s and AEq = 1.16 mm s at 4.2 K [157]. The electronic structure of a different salt was explored in depth by DFT calculations, magnetic susceptibility, MCD measurements, far-infra red spectroscopy and applied-field Mossbauer spectroscopy [158]. 

In summary, it is non-trivial to implement magnetic resonance pulse sequences which allow us to monitor unambiguously the decrease in absolute concentration of reactant species and associated increase in product species, but measures of relative concentrations from which conversion and selectivity are calculated are much easier to obtain. However, if such measurements are to be deemed quantitative the spectra must be free of (or at least corrected for) relaxation time and magnetic susceptibility effects. 

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