The periodic table (PT) is used in all natural science areas. It is a compact and approximate way to summarize both the electronic shell structure of individual atoms, and other basic properties. Pyykkö uncovered the extended periodic table from atomic number 1 to 172 by Extended Average Level Dirac-Fock calculations in 2010. In particular the 8p* shell calculations revealed the place of element 139 and 140 in PT. In this text of SCCJ Cafe- Season 3, PT is discussed. Also, the culture of quantum chemistry and life in Finland are briefly touched upon.
This article investigates the relationship between the characteristic radii from an anion nucleus, by comparing RSP (the Shannon−Prewitt anion radius based on Pauling's theory with Goldschmidt's experimental data) with Req, at which the charge densities of one anion and cation respectively are equal in the interatomic region in an ionic crystal. Calculations were performed via the SIWB (surrounding or solid Coulomb-potential-induced well for basis set) method reported previously using the discrete variational (DV) molecular orbital method in a density functional theory (DFT) scheme. Numerical basis atomic orbitals were derived via the method introduced by the present author in a previous paper, in which a spherically symmetric well potential generated by the crystal Coulomb potential was added solely to the potential for electrons within the anion radius on the isolated anion. The radius Req for the well radius was determined to satisfy the conditions that the input value of the well radius for the anion coincides with the output value of Req after sequential repetitions. The analysis also obtained the radius Rmin, where the sum of the above two charge densities takes the minimum. It was clear that Req is relatively similar to the Shannon−Prewitt anion radius.
Equations of state (EOS) are proposed for a system consisting of a perfect solid and a perfect liquid made up of single spherical molecules. The Lennard–Jones interaction is assumed for this system. Molecular dynamics simulations are performed to determine the temperature and density dependences of the internal energy and pressure. The internal energy term in the EOS is the sum of the average kinetic and potential energies at 0 K and the temperature-dependent potential energy. The temperature-dependent term of the average potential energy is assumed to be a linear function of the temperature and its coefficient is expressed as a polynomial of the number density. The pressure is expressed in a similar way, where the pressure satisfies the thermodynamic EOS. The equilibrium condition is solved numerically for the phase equilibrium of argon. The Gibbs energy gives a reasonable transition pressure for three-phase equilibrium in argon. The thermodynamic properties at low pressures have significant temperature dependences.
Tryptanthrin (T) and eight of its monosubstituted derivatives (T2NH2, T2Cl, T2Br, T2NO2, T8OMe, T8Me, T8F, and T8Br) were synthesized, and their antimicrobial activities were investigated against a fungus (Malassezia furfur) and a gram-positive bacterium (methicillin-resistant staphylococcus aureus, MRSA). Antimicrobial activities of these derivatives were influenced by the substituents on tryptanthrin, with the halogen-substituted tryptanthrin derivatives (T2Cl, T2Br, T8F, and T8Br) showing the highest potency against M. furfur and MRSA. Therefore, semiempirical molecular orbital calculations (PM3) were performed on T and its eight derivatives to investigate the cause of the differences in their antimicrobial activities. The results of the calculations showed that antimicrobial activities could be related to the electrophilicity of the carbonyl carbon of the five-membered ring.