Photoionization of highly charged ions using an ECR ion source and undulator radiation

Photoionization of Xe4+ to Xe7+ ions was studied by combining an electron cyclotron resonance ion source with synchrotron radiation. Multiconfiguration Dirac-Fock calculations were performed to interpret the data. Many autoionization lines were measured and identified, resulting from excitation of a 4d electron into nf and np orbitals followed by Auger decay of the excited states. Continuum photoionization is negligible for the higher members of the isonuclear series.     

Models for D → Kπℓν decay

We present the predictions of various models for D → Kπ?ν decay for the K-π system in the region of the K¹ resonance. In this system both vector and axial vector currents can be studied. One of these models also applies to the D → K?ν decay mode. Also, tests are given for general Kπ?ν of the pure vector hypothesis for the (c, s) current.     

The first structurally confirmed paddlewheel compound with an M(2)(7+) core: [Os(2)(hpp)(4)Cl(2)](PF(6))

Oxidation of Os(2)(hpp)(4)Cl(2), 1 (hpp = the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), with (FeCp(2))PF(6) produces air-stable [Os(2)(hpp)(4)Cl(2)]PF(6), 2. This is the first structurally confirmed metal-metal bonded paddlewheel compound having an M(2)(7+) core. The Os-Os distances for two crystalline forms, 2.2acetone and 2.hexane, are 2.3309(4) and 2.3290(6) A, respectively. EPR, (1)H NMR, and magnetization data indicate that 2 has an unpaired electron and an exceptionally low g value of 0.791 +/- 0.037. An electrochemical study shows that there is a quasireversible wave corresponding to a more highly oxidized species with an unprecedented Os(2)(8+) core.     

On energy focusing with multiple sources in an inviscid field

A concept has been proposed for focusing underwater energy. An array of independently detonated spherical TNT charges has been suggested to achieve this aim. The goal of the present research effort is to model this system and identify optimal array geometry and detonation timing. A reduced-order model must be developed due to the highly iterative nature of most optimization algorithms. The fast computational speed required by the optimization problem renders the use of the sophisticated numerical solvers impractical. An analytical, physics-based model must be developed to satisfy the computational time and accuracy demands of the multiple charge problem. This model must capture shock propagation speed, pressure–time histories throughout the fluid domain, and shock wave interaction phenomena. Such a model is presented herein.