Burkhard Fricke

On the correlation between electric polarizabilities and the ionization potential of atoms

It is found that the electric dipole polarizabilities of neutral atoms correlate very strongly with their first ionization potential within the groups of elements with the same angular momenta of the outermost electrons. As the latter values are known very accurately, this allows a very good (<30%) prediction of various atomic polarizabilities.

All-electron Dirac—Fock—Slater SCF calculations of the Au2 molecule

Abstract All-electron Dirac—Fock—Slater SCF clculations of the Au 2 molecule have been carried out using relativistic numerical atomic basis functions. In order to get a numerically accurate potential energy curve an improved calculation of the direct Coulomb potential has been taken into account. The relativistic effect inthe binding energy, the bond distance and the vibration frequency of the ground state potential energy curve have been studied in comparison with consistent non-relativistic results.

Dirac-Fock-Slater calculations for the elements Z=100, fermium, to Z=173

Supported by Gesellschaft fur Schwerionenforschung (GSI), Germany, and partially (G.S.) by the Bundesministerium fur Forschung und Technology (BMFT)

The electronic structure and properties of group 8 oxides MO4, where M=Ru, Os, and Element 108, Hs

Fully relativistic density functional calculations have been performed for group 8 tetroxides MO4, where M=Ru, Os, and element 108, Hs. The electronic structure analysis has shown HsO4 to be very similar to OsO4, with the covalence and stability increasing from OsO4 to HsO4. Using models of atom-slab interactions, adsorption enthalpies of RuO4 and HsO4 on the quartz surface have been calculated using some models of physisorption. The volatility of the single species was shown to have the following trend, RuO4<OsO4⩽HsO4, with differences in the adsorption enthalpies between the species being almost within the experimental uncertainty of ±1.5 kJ/mol.

Intermetallic compounds of the heaviest elements: the electronic structure and bonding of dimers of element 112 and its homolog Hg

Abstract Fully relativistic (four-component) density-functional calculations were performed for the element 112 dimers (112)X (X = Pd, Cu, Ag and Au) and those of its lighter homolog, Hg. A relatively small decrease of about 15–20 kJ/mol in bonding was found from the HgX to (112)X compounds. Respectively, the bond lengths were increased by 0.06 A on the average. The Mulliken population analysis has shown this effect to be a result of a decreasing contribution of the relativistically stabilized 7s-AO of element 112 to bonding. The following trend in the binding energies was predicted for (112)X as a function of X: Pd >Cu>Au>Ag, exactly as the trend obtained experimentally for adsorption of Hg on the corresponding metal surfaces.

Ionization potentials and radii of atoms and ions of element 104 (unnilquadium) and of hafnium (2+) derived from multiconfiguration Dirac-Fock calculations

Multiconfiguration relativistic Dirac–Fock (MCDF) values have been computed for the first four ionization potentials (IPs) of element 104 (unnilquadium) and of the other group 4 elements (Ti, Zr, and Hf). Factors were calculated that allowed correction of the systematic errors between the MCDF IPs and the experimental IPs. Single ‘‘experimental’’ IPs evaluated in eV (to ±0.1 eV) for element 104 are: [104(0),6.5]; [104(1+),14.8]; [104(2+),23.8]; [104(3+),31.9]. Multiple experimental IPs evaluated in eV for element 104 are: [(0−2+),21.2±0.2]; [(0−3+),45.1±0.2]; [(0−4+),76.8±0.3]. Our MCDF results track 11 of the 12 experimental single IPs studied for group 4 atoms and ions. The exception is Hf(2+). We submit our calculated IP of 22.4±0.2 eV as much more accurate than the value of 23.3 eV derived from experiment.

On the chemistry of superheavy elements around Z = 164

Supported by the Bundesministerium fur Wissenschaftliche Forschung and by the Deutsche Forschungsgemeinschaft.

Relativistic effects in physics and chemistry of element 105. II. Electronic structure and properties of group 5 elements bromides

Relativistic self‐consistent charge Dirac–Slater discrete variational method calculations have been done for the series of molecules MBr5, where M=Nb, Ta, Pa, and element 105, Ha. The electronic structure data show that the trends within the group 5 pentabromides resemble those for the corresponding pentaclorides with the latter being more ionic. Estimation of the volatility of group 5 bromides has been done on the basis of the molecular orbital calculations. According to the results of the theoretical interpretation HaBr5 seems to be more volatile than NbBr5 and TaBr5.

Relativistic effects in physics and chemistry of element 105. III. Electronic structure of hahnium oxyhalides as analogs of group 5 elements oxyhalides

Electronic structures of MOCl3 and MOBr3 molecules, where M=V, Nb, Ta, Pa, and element 105, hahnium, have been calculated using the relativistic Dirac–Slater discrete‐variational method. The character of bonding has been analyzed using the Mulliken population analysis of the molecular orbitals. It was shown that hahnium oxytrihalides have similar properties to oxytrihalides of Nb and Ta and that hahnium has the highest tendency to form double bond with oxygen. Some peculiarities in the electronic structure of HaOCl3 and HaOBr3 result from relativistic effects. Volatilities of the oxytrihalides in comparison with the corresponding pentahalides were considered using results of the present calculations. Higher ionic character and lower covalency as well as the presence of dipole moments in MOX3 (X=Cl, Br) molecules compared to analogous MX5 ones are the factors contributing to their lower volatilities.

Zur Vakuumpolarisation in Myonenatomen

The various approximations of vacuum polarization potential and the higher order corrections up to α3 are reviewed and quantitatively dicussed. The quadrupol part of the vacuum polarization is established. It leads rather straight forward to a small contribution of vacuum polarization to nuclear polarization. These effects are quantitatively investigated.