Neodymium electronic structure

The electronic structure and chemical bonding of the neodymium compound Nd[N(SiMe3>2]3 has been studied by the INDO method [24]. The net charge on the Nd atom was found to be 0.254 and from this it is concluded that the Nd-N bonds have a co-... 

Neodymium. Neodymium can be present in relatively high concentrations in fluorapatites. Gaft et al. (2001a) lists Nd analyses for several natural apatites that are higher than any other REE except Ce, and at a concentration level of about 40% of the Ce value. Nd emission is well into the IR, and it is not sensitized by most of the other REE. Hence, Nd emission is expected to be relatively independent of other impurities, and will not contribute to visible luminescence. However, Nd -doped synthetic apatites are excellent laser materials, due to several physical attributes of the Nd electronic structure in the host lattice. Detailed evaluation of the optical properties of Nd in Ba fluorapatite... 

Leverenz HW (1968) An Introduction to Luminescence of Solids. Dover Publications, New York Louis-Achille V, DeWindt L, Defranceschi M (2000) Electronic structure of minerals The apatite group as a relevant example. Inti J Quantum Chem. 77 991-1006 Loutts GB, Hong P, Chai BHT (1994) Comparison of neodymium laser hosts based on a fluoro-apatite structure. Mater Res Soc 1994 45-49... 

The elements after Xe have this electronic configuration, plus electrons in the orbits of 4f, 5d, 6s, and so on. There are three elements. Cesium (Cs), barium (Ba), and lanthanum (La), between Xe and the RE elements. Cs has one 6s electron and Ba has two 6s electrons, while La has two 6s and one 5d electrons. When it comes to RE elements, the electrons start to fill the inner vacant 4f orbits. For instance, the first RE element Ce has only one electron in the f orbit, so that its configuration is [Xe]6s 4f 5d, while neodymium (Nd) has four electrons in the f orbit, i.e., its electron structure is [Xe]6s 4f. ... 

Now let us consider the effect of crystal environment on the magnetic moment of the lanthanides. In Table 10, we show the results of calculations of the magnetic moment of neodymium on several common crystal lattices. A trivalent Nd ion yields a spin moment of 3/lb and an orbital moment of 6/ib- In the final two columns of Table 10, we see that the SIC-LSD theory yields values slightly less than, but very close to, these numbers. This is independent of the crystal structure. The valence electron polarization varies markedly between different crystal structures from 0.34/ib on the fee structure to 0.90/Zb on the simple cubic structure. It is not at all surprising that the valence electron moments can differ so strongly between different crystal structures. The importance of symmetry in electronic structure calculations cannot be overestimated. Eor example, the hep lattice does not have a centre of inversion symmetry and this allows states with different parity to hybridize, so direct f-d hybridization is allowed. However, symmetry considerations forbid f-d hybridization in the cubic structures. Such differences in the way the valence electrons interact with the f-states will undoubtedly lead to strong variations in the valence band moments. 

Another difference is that the 5/orbitals have a greater spatial extension relative to the Is and Ip orbitals than the 4/orbitals have relative to the 6s and 6p orbitals. The greater spatial extension of the 5/orbitals has been shown experimentally the esr spectrum of UF3 in a CaF2 lattice shows structure attributable to the interaction of fluorine nuclei with the electron spin of the U3+ ion. This implies a small overlap of 5/ orbitals with fluorine and constitutes an / covalent contribution to the ionic bonding. With the neodymium ion a similar effect is not observed. Because they occupy inner orbitals, the 4/ electrons in the lanthanides are not accessible for... 

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