Papers by Keyword: Muon

Abstract: Au nanocluster may exhibit magnetic behaviour in contrast to its bulk state diamagnetic characteristic. We have used four functionals, namely, B3LYP, LSDA, HSEH1PBE and PBEPBE, in DFT calculations to examine the effect of different functionals on the structure of Au₂₃(SR)₁₆ nanocluster. The correct optimized structure Au₂₃(SR)₁₆ nanocluster that has a lower energy was found to be important to study possible muon sites and its associated hyperfine coupling constant. Our computational investigation shows that the B3LYP functional optimized structure resulted in lower total energy of the system as compared to the one produced by using the other functionals.

Abstract: An overview of the RIKEN-RAL Muon Facility is reported. The RIKEN-RAL Muon Facility has been established at the Rutherford-Appleton Laboratory in the UK in 1992 and started to be in used for material science studies from 1994 by applying intense pulsed muon beams. More than 380 publications have been published in international journals and more than 100 domestic and international collaborations have been organized. As an example of those collaborative studies, a preliminary result of one recent experimental study on the magnetism in gold nano-cluster is reported. Additionally, a recent computational result on a local effect induced by an injected muon is reported in order to show how the presence of the muon leads to a local deformation of the crystal structure, thus changing the muon’s own position in finding the final stopping site self consistently.

Abstract: Me₄P[Pd(dmit)₂]₂ is an organic magnet that show long range antiferromagnetic ordering as indicated by Muon Spin Rotation measurements. Three muon centers were observed in the material. To determine the muon stopping sites, we have employed the Molecular Orbital Cluster Method to study the electronic structure of muonated Me₄P[Pd(dmit)₂]₂. We used a cluster containing 1 formula unit in our investigations and applied the Density Functional Theory method. Three µ⁺ centers in the vicinity of three chemically non-equivalent sulfur sites, namely thione, thiol and thiolate were examined. All three µ⁺ sites were found to be energetically stable. In the pure Me₄P[Pd(dmit)₂]₂ cluster, the spin densities of the doublet state system is spread throughout the entire dimer. Spin density of only about 0.13 is localized around the thiolate moiety. For all three µ⁺ centers, the lattice relaxation effect is important to stabilize the sites energetically.