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J exchange coupling

Table 9.2 Structural data of the Gd(III)-Cu(II) complexes, Cu-O-Gd—O torsion angle, and experimental J exchange coupling constants. ... Table 9.2 Structural data of the Gd(III)-Cu(II) complexes, Cu-O-Gd—O torsion angle, and experimental J exchange coupling constants. ...
Forbes M D E, Closs G L, Calle P and Gautam P 1993 The temperature dependence of the exchange coupling in polymethylene biradicals. Conclusions regarding the mechanism of the coupling J. Phys. Chem. 97 3384-9... [Pg.1621]

Forbes M D E 1993 The effect of localized unsaturation on the scalar exchange coupling in flexible biradicals J. Phys. Chem. 97 3390-5... [Pg.1621]

Figure 10 presents the Curie temperature (T ) vs the TM-content (x) for Co- and Fe-based biaary alloys. Alloying rare-earth elements with small amounts of transition metals (x < 0.2) leads to a decrease ia Curie temperature. This is particularly obvious ia the Gd—Co system where it corresponds to a nonmagnetic dilution similar to that of Cu (41,42). This iadicates that TM atoms experience no exchange coupling unless they are surrounded by a minimum number j of other TM atoms. The critical number is j = 5 for Fe and j = 7 for Co. The steep iacrease of for Co-based alloys with x about 0.7 is based on this effect. [Pg.144]

Drillon M, Darriet J (1992) Progress in Polymetallic Exchange-Coupled Systems, some Examples in Inorganic Chemistry. 79 55-100 Duffy JA (1977) Optical Electronegativity and Nephelauxetic Effect in Oxide Systems. 32 147-166... [Pg.245]

The two spins 5a and 5b are assumed to be local, associated with the two sites a and b, respectively. The parameter J is the so-called exchange-coupling constant, which expresses the strength of the (super)exchange interaction between the... [Pg.128]

Consider now the limiting case of strong exchange coupling. When / > > A, R x J, and the 43 and 31 transitions are forbidden. The 42 and 21 transitions are at equal energy and so we have only ... [Pg.116]

Figure 6.1 Stick spectra for a dinitroxide biradical with a= 13 G for various values of the exchange coupling constant J. (Several very small, widely spaced resonances have been omitted for J=2A and J=5A.)... Figure 6.1 Stick spectra for a dinitroxide biradical with a= 13 G for various values of the exchange coupling constant J. (Several very small, widely spaced resonances have been omitted for J=2A and J=5A.)...
The bis(phenoxyl)zinc(II) species [Znn(L//BuMet )], which has been electrochemi-cally generated from five-coordinate [Znn(L"BuMet)], possesses a diamagnetic ground state (5) = 0). This diamagnetism means that the spins in this diradical are antiferromag-netically exchange-coupled (J = -3.2 cm1 H = -2JSyS2 Si = S2= 1/2) (145). [Pg.171]

M. Uhl and J. Kiibler, Phys. Rev. Lett., 77, 334 (1996). Exchanged-Coupled Spin-Fluctuation... [Pg.244]

A number of cases have been reported in the literature where the exchange between pairs of ions in a lattice is piedominant, i.e., ions aie exchange coupled in pairs because of their proximity. An example of this is copper acetate 168), where the copper ions occur in pairs which are relatively close, so that the spins of pairs of copper ions are coupled together to form a singlet state (paired spins) and a triplet state (unpaired spins). Resonance measurements 158) permit determination of the magnitude and sign of J. [Pg.93]


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