Electron configurations superheavy elements

Fricke, B. (1975) Superheavy elements a prediction of their chemical and physical properties. Structureel Bonding, 21,89-144. Eliav, E., Kaldor, U., Schwerdtfeger, P., Hess, B. and Ishikawa, Y. (1994) The Ground State Electron Configuration of... 

Table 1.1 Place of the Transactinoid/Superheavy Elements in the Mendeleev Periodic Table of the Elements. Emphasized are the calculated and just expected ground state electronic configurations...

The development of correlation schemes at the highest levels of theory (the CCSD(T) technique) allowed for very accurate DCB predictions of atomic properties for the heaviest elements up to Z=122 (see Chapter 2 in this book). Reliable electronic configurations were obtained assuring the position of the superheavy elements in the Periodic Table. Accurate ionization potentials, electron affinities and energies of electronic transitions (with the accuracy of below 0.01 eV) are presently available and can be used to assess the similarity between the heaviest elements and their lighter homologs in the Periodic Table. 

The superheavy elements are leading to deeper understanding of nuclear chemistry and the periodic table much as the lanthanides did at the start of the 20th century and the actinides did in mid-century. The favored +3 oxidation states of the lanthanides have electronic configurations 4f, 4f, 4f. .. 4f 4f 4f for the 14 consecutive lanthanides Ce through Lu respectively. These rare earths are chemically similar (and hard to separate) because their 4f orbitals exert little influence on reactivity. When Glenn T. Seaborg synthesized americium (95) and curium (96) in 1944, he discovered that, like the lanthanides, they readily form +3 oxidation states and fill 5f orbitals. In 1944, he proposed a new transi-... 

In conjunction with these efforts, calculations were made to predict the chemical properties of the Superheavies so that likely ores could be chosen for investigation and separation schemes devised. Separation techniques were developed to purify and identify elements with lifetimes as short as a thousandth of a second. Models were developed to predict such aggregate properties as entropies from samples as small as 500 atoms. Ground-state electron configurations, oxidation states, ionization energies, metallic radii, ionic radii, densities, melting points. 

Superheavy elements exist on the edge of physical possibility, both in terms of their electron configurations and their nuclear stmcture. They are difficult to produce and study, those we have studied so far do not exist long enough to allow any industrial application. Yet they open up a tmly interdisciplinary field of study grounded in both chemistry and physics and they can teach us a great deal about the most extreme configurations of protons, neutrons and electrons available. 

The main aim of chemical research in the area of the heaviest elements is to assign a new element its proper place in the Periodic Table. Conceptually, it is the atomic number, Z, and electronic configuration of an element that define its position there. Since the latter cannot be measured for the very heavy elements, information on its chemical behavior is often used for this purpose. Unfortunately, with increasing nuclear charge cross-sections and production rates drop so rapidly that such chemical information can be accessed only for elements with a half-life of the order of at least few seconds and longer (see Synthesis of Superheavy Elements )- In this case, some fast chemistry techniques are used (see Experimental Techniques ). 

A practical instrument for many-electron open shell system is still the MCDF method. There are several modifications of it implemented into computational codes of Desclaux [57], developed further by Indelicato [36], of Grant [58] and Frose-Fisher [59]. Based on the Cl technique, the MCDF method accounts for most of the correlation effects while retaining a relatively small number of configurations. It can treat a large number of open shell configurations and can be applied to elements with any number of valence electrons. It omits, however, dynamic correlation, since excitations of the type (nj) n j) cannot be handled, and some core polarization, which makes it less accurate than the DC(B) CC methods. An average error for IP of heavy elements is about 1 eV. Calculations for many heaviest and superheavy elements were performed with the use of the AL version [23-31], as well as with a more accurate OL one [36]. 

Nefedov, V.I., Trzhaskovskaya, M.B., Yarzhemcky, V.G. Electronic configurations and the Periodic Table for superheavy elements. Doklady Phys. Chim. 408, 149-151 (2006)... 

Malli, G.L. Thirty years of relativistic self-consistent field theory for molecules Relativistic and electron correlation effects for atomic and molecular systems of transactinide superheavy elements up to ekaplutonium E126 with g-atomic spinors in the ground state configuration. Theor. Chem. Ace. 118, 473 82 (2007)... 

Table 1 Ground State Configurations and Symmetries of the Superheavy Elements. In all Relativistic Configurations the One widi the Highe.st Coefficient in the Multi-configuration Dirac-FtK k (MCDF) Expansion had the Maximum Number of Electrons in the (y — 1 /2) Orbital of any Open Shell (Except for Element 107) ...

K. Umemoto and S. Saito, Electronic configurations of superheavy elements, J. Phys. Soc. Japan 65, 3175 (1996). 

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