Relativistic alkali metal

Thallium may be described as a relativistic alkali metal the downshift in energy of the 65 orbital, due to a combination of relativity and shell structure effect, favours the oxidation state I over III (see 4.2.22). The stability of the oxidation state +1... 

The variation of the melting points of the transition metals, as well as those of the alkali metals and alkali earth metals of the same period, are displayed in Fig. 2.4.6. It is seen that the uppermost curve (that for the elements of the sixth period) starts from Cs, increasing steadily and reaching a maximum at W. Beyond W, the curve starts to decrease and reach the minimum at Hg at the end. It is believed that this trend is the result of the relativistic effects. 

For electron scattering on lighter alkali-metals, spin asymmetry is due to the Pauli exclusion principle, not to relativistic effects. It tests the relationship between direct and exchange elements of the calculation. Since it is a ratio it is easier to measure accurately than the differential cross section, which varies over many orders of magnitude in the case of sodium. 

Structural, reactivity, and optical properties of noble metal clusters attracted theoretical [47, 49, 104, 166-179] and experimental studies [178-192] over the years because of their relatively simple electronic nature in comparison with transition metals and their similarity to -sheU alkali metals. This is particularly the case for the Ag atom with a large s-d gap in contrast to the An atom. In the latter case, the s-d gap is considerably smaller, because the relativistic effects play an essential role— for example, strongly influencing the energy of an i-orbital. These differences in electronic structure are also reflected in the... 

Quantum electrod)mamic (QED) effects are known to be very important for inner-shells, for example, in accurate calculations of X-ray spectra [61]. For highly charged few electron atoms they were found to be of similar size as the Breit correction to the electron-electron interaction [62]. Similar effects were also found for valence ns electrons of neutral alkali-metal and coinage metal atoms [63]. They are of the order of 1-2% of the kinetic relativistic effects there. The result for the valence ns electron is a destabilization, while for (n-l)d electron is an indirect stabilization. In the middle range (Z = 30-80) both the valence-shell Breit and the Lamb-shift terms behave similarly to the kinetic... 

Safronova, M.S., Johnson, W.R., and Derevianko, A., Relativistic many-body calculations of energy levels, hyperfme constants, electric-dipole matrix elements, and static polarizabilities for alkali-metal atoms, Phys. Rev. A, 60, 4476-4487, 1999. 

Bryce and Autschbach performed the accurate calculation of the isotropic and anisotropic (AT) parts of indirect nuclear spin spin coupling tensors for diatomic alkali metal halides (MX M = Li, Na, K, Rb, Cs X = F, Cl, Br, I) with the relativistic hybrid DFT approach. The calculated coupling tensor components were compared with experimental values obtained from molecular-beam measurements on diatomic molecules in the gas phase. Molecular-beam experiments offer ideal data for testing the success of computational approaches, since the data are essentially free from intermolecular effects. The hyperfine Hamiltonian used in analyzing molecular-beam data contains Hc IkDIi and //C4/a /l terms. The relationships between the parameters C3 and C4, used in molecular-beam experiments, and Rdd, A/, and used in NMR spectroscopy, are summarized in the following equations ... 

Lim, I.S., Pernpointer, M., Laerdahl, J.K., Schwerdtfeger, P., Neogrady, P., Urban, M. Relativistic coupled-cluster static dipole polarizabilities of the alkali metals from Li to element 119. Phys. Rev. A. 60, 2822-2828 (1999)... 

Examination of the results obtained so far indicates that the chemical behavior of relativistic element 111 is totally different from its nonrelativistic equivalent. Element 111 will be rather inert but has a high electronegativity (the diatomic (lll)H has a small dipole moment with H having a small negative formal chaige), while nonrelativistic element 111 would behave more like a laige alkali metal. This agrees nicely with the predictions earlier made by Fricke. ... 

E. Eliav, U. Kaldor, and Y. Ishikawa, Ionization potentials and excitation energies of the alkali-metal atoms by the relativistic coupled cluster method, Phys. Rev. A 50, 1121 (1994). 

The experimentally determined MX bond distances of 27 dihalides of the Group 2 and 12 metals are listed in Table 2. In most cases they are accurate to better than 2 pm. As in the case of the alkali metal monohalides, the bond distances of the Group 2 metal dihalides increase monotonically with increasing atomic numbers of the metal or halogen atoms. The bond distances in the Group 12 metal dihalides increase with the atomic number of the halogen, but the variation with the atomic number of the metal breaks the pattern Hg forms shorter bonds than Cd. The shortening is probably due to a combination of relativistic effects and the lanthanide contraction [17]. 

The ligand CN forms bonds with transition-metal atoms that are very covalent in nature, resulting in strong electronic delocalization. Added to this, the presence of a relativistic atom induces complex and interesting effects. The low-spin complex ion [Ir(CN)s]3-, in which Ir is in the unusual formal oxidation state +2, has been obtained by irradiation of the hexacoordinated diamagnetic Ir(+3) complex with electrons or X-rays in solid alkali halide matrices [98]. [Ir(CN)5]3 has a square-pyramidal structure (see Fig. 9) and one unpaired electron in the HOMO. 

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