Papers by Keyword: Muonium

Abstract: We have performed First Principle computational studies utilizing Molecular-Orbital (MO) Cluster method to examine the electronic structure of muonated La₂CuO₄. Based on recent works, we investigated three suggested muon sites in La₂CuO₄. Two possible muon sites are located near the apical oxygen O(a), and the other one is near the planar oxygen O(p). The calculations were performed at the HF/Gen level of theory. The results of our investigation show that there is a very significant covalency effect between copper and oxygen. In the pure system, the effective charge on Cu is 0.77 while the charge on the oxygens is around –1.8. In the muonated system, the charge on Cu reduces to 0.58. The spin density at Cu is 0.78 in the pure system and becomes 0.70 when muon is added. As for the muon, the charge and spin density are +0.22 and –0.0026 respectively.

Abstract: We carried out ab initio electronic structure calculations in the frameworks of the Density Functional Theory (DFT) to study the electronic structures and hyperfine interaction of muonium (Mu) in imidazole (C₃H₄N₂) and 1–methylimidazole (CH₃C₃H₃N₂). The local energy minima and hyperfine interactions of the Mu trapped at the three studies sites were determined by performing geometry optimization procedure. The results show the total energies for all three studied sites are close to one another. The Mu hyperfine interactions were also determined, with the corresponding values vary from 343.00 MHz to 471.28 MHz for the imidazole–Mu cluster, and from 380.21 MHz – 465.57 MHz to 475.93 MHz for the cluster of 1–methylimidazole–Mu, respectively.

Abstract: The equilibrium structure of muoniatedtetraphenylgermane (GePh₄Mu) was studied using the first principle Density Functional Theory (DFT) method. Three muonium (Mu) trapping sites were considered, namely ortho, meta, and para positions on one of the phenyl rings. Geometry optimization procedure was utilized to determine the local energy minimum for all the systems. The total energies corresponding to Mu at the three positions are very similar to each other. For the meta case, the corresponding energy is higher than the other two sites by only about 0.03 eV. The hyperfine parameters of Mu were also calculated. The Mu isotropic hyperfine coupling constants were found to be 441.85 MHz, 449.80 MHz, and 439.01 MHz for the ortho, meta, and para cases, respectively. The anisotropic value was calculated to be very small.

Abstract: A unified mechanism describing formation of Ps and Mu atoms in condensed matter, radiolytic hydrogen in water and products of Auger ionization in Moessbauer atoms is presented. All these processes are similar to the Ps formation mechanism in a condensed molecular milieu.