Zeeman electronic

The spin Hamiltonian used to model the deuterium ligand hyperfine interaction consisted of nuclear Zeeman, electron-nuclear hyperfine and nuclear quadrupole terms. 

The nuclear interactions observed in ENDOR are three the nuclear Zeeman, electron-nuclear hyperfine, and (for I > i) the nuclear electric quadrupole interactions. The Hamiltonian H including these nuclear interactions in an external magnetic field B is given as... 

This is called the Zeeman electronic effect and the energy difference, AE, is given by ... 

Fig. 4.25 Under an applied magnetic field, Bq, the interaction between an unpaired electron and the magnetic field results in a splitting of the energy levels (the Zeeman electronic effect).

The spins of such nuclei interact magnetically with the unpaired electron and give rise to a hyperfine interaction. There is a direct analogy here with coupling of nuclear spins in NMR spectroscopy. The hyperfine interaction is added to the Zeeman electronic interaction, leading to a further splitting of the energy levels (eq. 4.22). 

The transition between levels coupled by the oscillating magnetic field B corresponds to the absorption of the energy required to reorient the electron magnetic moment in a magnetic field. EPR measurements are a study of the transitions between electronic Zeeman levels with A = 1 (the selection rule for EPR). 

The coupling constants of the hyperfme and the electron Zeeman interactions are scalar as long as radicals in isotropic solution are considered, leading to the Hamiltonian... 

The first temi describes the electronic Zeeman energy, which is the interaction of the magnetic field with the two electrons of the radical pair with the magnetic field, Bq. The two electron spins are represented by spin... 

Not only can electronic wavefiinctions tell us about the average values of all the physical properties for any particular state (i.e. above), but they also allow us to tell us how a specific perturbation (e.g. an electric field in the Stark effect, a magnetic field in the Zeeman effect and light s electromagnetic fields in spectroscopy) can alter the specific state of interest. For example, the perturbation arising from the electric field of a photon interacting with the electrons in a molecule is given within die so-called electric dipole approximation [12] by ... 

From accurate measurements of the Stark effect when electrostatic fields are applied, information regarding the electron distribution is obtained. Further Information on this point is obtained from nuclear quadrupole coupling effects and Zeeman effects (74PMH(6)53). 

Hfi includes a nuclear Zeeman term, a nuclear dipole-dipole term, an electron-nuclear dipole term and a term describing the interaction between the nuclear dipole and the electron orbital motion. 

Another legacy of the late nineteenth century was identification of the electron by an appropriate interpretation of the Pieter Zeeman effect in 1896, and more especially by J. J. Thomson s experiments the... 

For electron spin resonance (ESR) measurements, the sample is placed in a resonant microwave cavity between the pole pieces of an electromagnet. The magnetic field is gradually increased, which induces a Zeeman splitting of the excila-... 

All instruments should be equipped with a background correction facility. Virtually all instruments now have a deuterium arc background correction. The Zeeman system is also available in instruments marketed by the Perkin-Elmer Corporation and the Smith-Hieftje system by Thermo Electron Ltd. 

The number of energy levels found to date, with the aid of the Zeeman effect and the isotope shift data, is 605 even and 586 odd levels for Pu I and 252 even and 746 odd for Pu II. The quantum number J has been determined for all these levels, the Lande g-factor for most of them, and the isotope shift for almost all of the Pu I levels and for half of those of Pu II. Over 31000 lines have been observed of which 52% have been classified as transitions between pairs of the above levels. These represent 23 distinct electron configurations. 

Thus both the (/-factor and the Upvalues affect Tq-S mixing. In general, the two radicals comprising the radical pair will have different gr-values and therefore different Zeeman energies [the first term in equation (12)]. Likewise the upvalues and hyperfine energies [the second term in equation (12)] will differ. The difference between the LPFs for two radicals is then given by equation (13), where gx and are the electronic y-factors... 

The electron-electron dipolar term, Ho, equals S1.D.S2. The tensor D is completely anisotropic and only mixes T-states with one another. It is therefore dropped. The nuclear Zeeman term, tlzi =... 

OIDEP usually results from Tq-S mixing in radical pairs, although T i-S mixing has also been considered (Atkins et al., 1971, 1973). The time development of electron-spin state populations is a function of the electron Zeeman interaction, the electron-nuclear hyperfine interaction, the electron-electron exchange interaction, together with spin-rotational and orientation dependent terms (Pedersen and Freed, 1972). Electron spin lattice relaxation Ti = 10 to 10 sec) is normally slower than the polarizing process. 

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