Magnetic dipolar transitions

J. P. Dahl d al. 28) identified the unknown band of BaNi(CN) 4, 4 H2O as magnetic dipolar transition Aig ipzg 6ig). This band should... 

The spectroscopy of the SD0 level is also a valuable tool to investigate the point symmetry of Eu3+ ions in materials. It is well-known that the 5D0 - 7F2 transition is electric-dipole in nature, while 5D0- -7Fi shows a magnetic-dipole character. 5D0-> 7F2 is totally forbidden in presence of an inversion center and it is allowed in the opposite case. Usually, in vitreous phases, where the symmetry is low, electric dipolar transitions exhibit the strongest intensity. The fluorescence spectra displayed in Fig. 8 show that both transitions have about the same intensity indicating that Eu3+ ions are in high-symmetry sites in fluorozirconate glasses, relatively to oxide glasses. 

Figure 6. Energy level scheme for a typical aromatic hydrocarbon. So denotes the electronic ground state, S the first excited singlet state and T the first excited triplet state. The triplet state is actually split into three sublevels by magnetic dipolar interaction of the triplet electrons (zero-field splitting). The dots and arrows denote the approximate populations and lifetimes of the sublevels for a typical, planar aromatic hydrocarbon. The lower panel shows schematically the time distribution of fluorescence photons (photoelectric pulses) for a single emitter undergoing singlet-tiiplet transitions leading to photon bunching.

Transitions arising from the Dq level of the 41 electronic configuration of are intensities between the magnetic dipolar Dq Fi ( 590 nm) and the electric dipolar Dq —> p2 ( 610 nm) transitions. The higher this ratio, the closer the local symmetry around Eu " " is to an inversion center. In the standard theory, the spontaneous emission of a integrated coefficient of the transition between two manifolds / and / is given by... 

L. Haggstrom, H. Annersten, T. Ericsson, R. Wappling, W. Karner, S. Bjarman, Magnetic dipolar and electric quadmpolar effects on the Mossbauer spectra of magnetite above the Verwey transition. Hyp. Interact. 5, 201-214 (1978)... 

Thompson et al., 1977), where the luminescent transitions (from 04 and Dj), changing / by one unit, are essentially magnetic dipolar and do not show extensive vibrational structure, whereas the other transitions are mainly vibronic (i.e., simultaneously changing the electronic and vibrational quantum numbers). The same behavior is observed (Serra and Thompson, 1976) in... 

---