Magnetic sub-level

On compression of non-hydrogen atoms the energy levels, which in this case are occupied by electrons, respond in the same way. Apart from level crossings, interelectronic interactions now also lead to an internal transfer of energy and splitting of the magnetic sub-levels, such that a single electron eventually reaches the ionization limit on critical compression. The calculated ionization radii obey the same periodic law as the elements and determine the effective size of atoms in chemical interaction. 

The first ODMR experiments, in which magnetic sub-levels of optically excited states were preferentially populated by excitation with circularly polarized light in a magnetic field ( optical pumping ) were conducted almost forty years ago by Geschwind and co-workers [54], Since then it has developed into a powerful tool to probe optical and electronic processes in a wide variety of semiconducting [55-57] and biological materials [58]. 

All the four magnetic sub-levels of Fe are displaced by the same amoimt by quadrupole interaction when the axially symmetric EFG tensor has its symmetry axis parallel to Bhf (Fig.4.7). 

In order to excite atomic magnetic sub-levels with 0 it is necessary to detect electrons outside of the forward direction. Information about those magnetic sub-levels can be obtained by investigating the angular correlations between electrons scattered inelastically from an atom and the photon emitted in the scattering plane. Such a study commenced in 1968 to investigate the excitation of the 2 P state of helixom and the first results were reported by Eminyan et al in 1973. 

From equation (3.83) we see that the external magnetic field removes the degeneracy of the fine-structure states y LSJMj >. In weak magnetic fields a set of equally spaced magnetic sub-levels is produced separated by energies of where = gj UgB/h is the Larmor angular frequency. 

Fig.11.1. Population densities of excited atoms per magnetic sub-level for gas discharges in which (a) thermal equilibrium exists,...

The isotope Hg has only two ground state magnetic sub-levels and so has served as an important test case for the basic theory of optical pumping, developed in more detail... 

Cohen-Tannoudji 1962). Although in Hg the ground state has four magnetic sub-levels, it is still true that by... 

This hypothesis is justified for systems such as " Hg or alkali atoms with zero nuclear spin since these atoms possess only two magnetic sub-levels in the ground state. For most atoms, however, many more sub-levels are involved, necessitating the introducion of further relaxation times. 

The photophysical processes associated closely with triplet states Ti include the delayed fluorescence, phosphorescence, nonradiative transition from T1 to So, and T T absorption or absorption to magnetic sub-levels of triplet state, as depicted in Fig. 1. 

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