Magnetic susceptibility theory

Motional magnetism, caused by rotation, vibration or translation of charged particles will be ignored. Thus all diamagnetism aspects will enter only implicitly. Thus we will not focus on static magnetic susceptibility theory (e.g. magnetizability) or measurements. 

On the general theory of magnetic susceptibilities of polynuclear transition metal compounds. J. S. Griffith, Struct. Bonding (Berlin), 1972,10, 87-126 (43). 

J.H. van Vleck, The Theory of Electric and Magnetic Susceptibilities, Oxford University Press, Oxford, 1932. 

Griffith JS (1972) On the General Theory of Magnetic Susceptibilities of Polynuclear Transitionmetal Compounds. 10 87-126 Grisham CM, see Mildvan AS (1974) 20 1-21... 

Van Vleck, J. H. Xhe theory of electronic and magnetic susceptibilities. Chap. VI. Oxford Xhe Clarendon Press 1932. 

Following the completion of the sintering study, a study was conducted to demonstrate that 663 K, the temperature at which all magnetic susceptibility measurements were taken, was indeed greater than Tq, . As discussed in the theory section, measurements were made at several temperatures until it was determined that plots of M/Mg versus H/T collapsed onto a single curve. It is clear from Figure 4 that Tqj, must be less than 450 K. That is, for any temperature above 450 K the average particle size was measured to be nearly 200 A in diameter. For smaller particles, Tq, will of course be an even lower temperature. This proves that all measurements made at 663 K were indeed accurate. 

The atomic properties satisfy the necessary physical requirement of paralleling the transferability of their charge distributions - atoms that look the same in two molecules contribute identical amounts to all properties in both molecules, including field-induced properties. Thus the atoms of theory recover the experimentally measurable contributions to the volume, heats of formation, electric polarizability, and magnetic susceptibility in those cases where the group contributions are found to be transferable, as well as additive additive [4], The additivity of the atomic properties coupled with the observation that their transferability parallels the transferability of the atom s physical form are unique to QTAIM and are essential for a theory of atoms in molecules that purports to explain the observations of experimental chemistry. 

Van Vleck JH (1932) Theory of electric and magnetic susceptibilities. Oxford University Press, New York... 

J.S. Griffith On the General Theory of Magnetic Susceptibilities of Polynuclear Transition-metal Compounds. 

Density functional theory and MC-SCF calculations have been applied to a number of pericyclic reactions including cycloadditions and electrocyclizations. It has been established that the transition states of thermally allowed electrocyclic reactions are aromatic. Apparently they not only have highly delocalized structures and large resonance stabilizations, but also strongly enhanced magnetic susceptibilities and show appreciable nucleus-independent chemical-shift values. 

The magnetic susceptibility relaxation is usually more important for than for Ti. In fact, this mechanism is often dominant in determining the proton linewidth in paramagnetic proteins at high magnetic fields (3). Gillis and co-workers have recently developed a theory for the related case of proton linewidth in colloidal solutions of so-called superparamagnetic particles (54,55). 

Penney and Schlapp, Van Vleck and others applied these results to interpret magnetic susceptibility data of paramagnetic transition group ions in crystals. More recently, the theory has been applied with considerable success to electron magnetic resonance data 126,140,14I) and to the optical spectra 142) of paramagnetic ions in solids. 

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