External magnetic field, effect

The impact of Equation 10.14 in the treatment of spin-polarized systems is in two directions on the one hand, it allows the inclusion of external magnetic field effects in the description of /V-electron systems on the other hand, when the limit of zero magnetic field is imposed, the formalism becomes useful for /V-electron systems having spin-polarized ground state in the absence of a external magnetic field. This... 

Internal Isotope and External Magnetic Field Effects... 

Conventional EPR techniques have been successfully used to measure the D and E values of matrix-isolated carbenes in the ground triplet state because the steady-state concentration of triplet species is sufficiently high in the system. The technique cannot be used, however, for excited species having triplet hfetimes of the order of 10-100 ns, since their steady-state concentration is too low. The D parameters are estimated from the external magnetic field effect on the T—T fluorescence decay in a hydrocarbon matrix at low temperamre. The method is based on the effect of the Zeeman mixing on the radiative and nonradiative decay rates of the T -Tq transition in the presence of a weak field. The D values are estimated by fitting the decay curve with that calculated for different D values. The D T ) values estimated for nonplanar DPC (ci symmetry) is 0.20... 

External magnetic field effects on the excited state properties of Rh(l) and Ir(I) complexes have been discussed. 

The radical anions of tram- and c/s-stilbene can be distinguished by ESR [503]. A radical ion pair has been observed by this method using trial-kylamines in acetonitrile [497], Electron back transfer (i.e., a reaction of the radical anion of frans-stilbene with the radical cation of the donor) opens a new pathway for intersystem crossing to the tram triplet state. Time-resolved resonance Raman spectroscopy of photoinduced electron transfer from amines to frans-stilbene has been reported [497,504], In the photooxidation of frans-stilbene the radical cation has been observed by flash photolysis using cyanoanthracenes [505-507], The radical cations of cis-and frans-stilbene were also produced by electron transfer from biphenyl to excited 9,10-dicyanoanthracene and subsequent electron transfer from stilbene to the radical cation of biphenyl [508]. External magnetic field effects... 

MHD theory [9-14] has been applied extensively [e.g. 15-21] in conjunction with convective diffusion theory [22-26] to the analysis of external magnetic field effects in the hydrodynamic and concentration boundary layer existing at the electrode/electrolyte interface [2,5,27]. 

In the PFR of 1-naphthyl acetate, the yield of 2-acetyl-l-naphthol exhibits a positive external magnetic field effect for the ester labeled by the magnetically active isotope C, but no effect for the C ester. This effect is explained by considering hyperfine coupling between H or C of the naphthoxyl radical and the unpaired electron of the acetyl radical, which is in agreement with formation of the in-cage product from a singlet radical pair [42],... 

Ichimura, K. and Watanabe, S., External magnetic field effect on chemical reactions (1). Photo-dimerization of acenaphthylene, Seni Kobunshi Zairyo Kenkyusho Kenkyu Hokoku, 108, 29, 1975. Gaplovsky, A, Donovalovd, J., Toma, S., and Kubinec, R., Ultrasound effects on photochemical reactions. 2. A study of ultrasound effects on some monomolecular and bimolecular photochemical reactions, /. Photochem. Photobiol. A Chem., 115,13,1998. 

Nakagaki, R, Hiramatsu, M., Watanabe, T, Tanimoto, Y., and Nagakura, S., Magnetic isotope and external magnetic field effects upon the photo-Fries rearrangement of 1-naphthyl acetate, /. Phys. Chem., 89, 3222, 1985. 

Minaev, B.F. Spin-orbit interaction in molecules and mechanism of the external magnetic field effect on luminescence. Opt. Spectrosc. (USSR) 44, 148 (1978)... 

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