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William & Mary

Arts & Sciences Articles

2006

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Nickel(Ii) And Cobalt(Ii) Nitrate And Chloride Networks With 2-Aminopyrimidine, Robert D. Pike, Mi Jung Lim, Ellen A. L. Wilcox, Tristan A. Tronic Nov 2006

Nickel(Ii) And Cobalt(Ii) Nitrate And Chloride Networks With 2-Aminopyrimidine, Robert D. Pike, Mi Jung Lim, Ellen A. L. Wilcox, Tristan A. Tronic

Arts & Sciences Articles

The coordination chemistry of 2-aminopyrimidine (PymNH2) with nickel(II) and cobalt(II) nitrate and chloride is reported, including seven new X-ray crystal structures. Two [Ni(NO3)2(PymNH2)2(OH2)] isomers were found (A: C2/c, a=13.3006(5), b=7.9727(3), c=28.5453(11), β=101.758(2), V=2963.48(19), Z=8 and B·1/2 acetone: P21/c, a=7.66060(10), b=10.6792(2), c=20.6790(3), β=100.2970(10), 1664.48(5), Z=4). In both cases one nitrate is monodentate and the other is chelating and the PymNH2 ligands coordinate through ring nitrogen atoms. Hydrogen bonding results in double sheet structure for isomer A, and a three dimensional channeled network for isomer B. [Co(NO3)2(PymNH2)2(OH2)] ( …


Escape Of Trajectories From A Vase-Shaped Cavity, Paul Hansen, Kevin A. Mitchell, John B. Delos Jun 2006

Escape Of Trajectories From A Vase-Shaped Cavity, Paul Hansen, Kevin A. Mitchell, John B. Delos

Arts & Sciences Articles

We consider the escape of ballistic trajectories from an open, vase-shaped cavity. Such a system serves as a model for microwaves escaping from a cavity or electrons escaping from a microjunction. Fixing the initial position of a particle and recording its escape time as a function of the initial launch direction, the resulting escape-time plot shows “epistrophic fractal” structure—repeated structure within structure at all levels of resolution with new features appearing in the fractal at longer time scales. By launching trajectories simultaneously in all directions (modeling an outgoing wave), a detector placed outside the cavity would measure a train of …


Electron Dynamics In Parallel Electric And Magnetic Fields, Christian Bracher, Tobias Kramer, John B. Delos Jun 2006

Electron Dynamics In Parallel Electric And Magnetic Fields, Christian Bracher, Tobias Kramer, John B. Delos

Arts & Sciences Articles

We examine the spatial distribution of electrons generated by a fixed energy point source in uniform, parallel electric, and magnetic fields. This problem is simple enough to permit analytic quantum and semiclassical solution, and it harbors a rich set of features which find their interpretation in the unusual and interesting properties of the classical motion of the electrons: For instance, the number of interfering trajectories can be adjusted in this system, and the turning surfaces of classical motion contain a complex array of singularities. We perform a comprehensive analysis of the semiclassical approximation and compare it to the quantum solution, …


Copper(I) Chloride Carbonyl Polymers, Austin B. Wiles, Robert D. Pike May 2006

Copper(I) Chloride Carbonyl Polymers, Austin B. Wiles, Robert D. Pike

Arts & Sciences Articles

Addition of bridging diamine ligands to methanolic solutions of CuCl under a CO purge produces the polymeric complexes [(CuCl)2(CO)2(biL)] (biL = diazabicyclo[2.2.2]octane (DABCO), piperazine (Pip), N,N‘-dimethylpiperazine (DMP)). X-ray crystal structures of the three complexes reveal rhombic OC−Cu(μ-Cl)2Cu−CO bridged by biL. Unsaturated bridging ligands fail to produce carbonyl-bearing products.


Motion Of An Electron From A Point Source In Parallel Electric And Magnetic Fields, Christian Bracher, John B. Delos Mar 2006

Motion Of An Electron From A Point Source In Parallel Electric And Magnetic Fields, Christian Bracher, John B. Delos

Arts & Sciences Articles

Negative ions undergoing near-threshold photodetachment in a weak laser field provide an almost pointlike, isotropic source of low-energy electrons. External fields exert forces on the emitted coherent electron wave and direct its motion. Here, we examine the spatial distribution of photodetached electrons in uniform, parallel electric and magnetic fields. The interplay of the electric and magnetic forces leads to a surprising intricate shape of the refracted electron wave, and mutiple interfering trajectories generate complex fringe patterns in the matter wave. The exact quantum solution is best understood in terms of the classical electron motion.


2,2′,3,3′-Tetra­Methyl-6,6′-Biquinoxaline, Ralph N. Salvatore, Jorden P. Kass, Ricky J. Paul Gibson, Cesar H. Zambrano, Robert D. Pike, Eric E. Dueno Jan 2006

2,2′,3,3′-Tetra­Methyl-6,6′-Biquinoxaline, Ralph N. Salvatore, Jorden P. Kass, Ricky J. Paul Gibson, Cesar H. Zambrano, Robert D. Pike, Eric E. Dueno

Arts & Sciences Articles

The molecule of the title compound, C20H18N4, has twofold rotational symmetry. Each aromatic ring of the fused quinoxaline ring system is skewed from the other by 4.93 (7)°. The two quinoxaline units make a dihedral angle of 43.52 (2)°


Thermal Desorption Of Hydrogen From Carbon Nanosheets, X. Zhao, R. A. Outlaw, J. J. Wang, M. Y. Zhu, Gregory D. Smith, B. C. Holloway Jan 2006

Thermal Desorption Of Hydrogen From Carbon Nanosheets, X. Zhao, R. A. Outlaw, J. J. Wang, M. Y. Zhu, Gregory D. Smith, B. C. Holloway

Arts & Sciences Articles

Carbon nanosheets are a unique nanostructure that, at their thinnest configuration, approach a single freestanding graphene sheet. Temperature desorption spectroscopy (TDS) has shown that the hydrogen adsorption and incorporation during growth of the nanosheets by radio frequency plasma-enhanced chemical vapor deposition are significant. A numerical peak fitting to the desorption spectra (300–1273K) via the Polanyi-Wigner equation showed that desorption followed a second order process, presumably by the Langmuir-Hinshelwood mechanism. Six peaks provide the best fit to the TDS spectra. Surface desorption activation energies were determined to be 0.59, 0.63, and 0.65eV for the external graphite surface layers and 0.85, 1.15, …


Bis([Mu]-Thio­Phene-2-Carbaldehyde Thio­Semicarbazonato)Bis­[Acetonitrile­Copper(I)] Bis­(Tetra­Fluoro­Borate), Robert D. Pike, Austin B. Wiles, Tristan A. Tronic Jan 2006

Bis([Mu]-Thio­Phene-2-Carbaldehyde Thio­Semicarbazonato)Bis­[Acetonitrile­Copper(I)] Bis­(Tetra­Fluoro­Borate), Robert D. Pike, Austin B. Wiles, Tristan A. Tronic

Arts & Sciences Articles

The title compound, [Cu2(C6H7N3S2)2(C2H3N)2](BF4)2, is a dimer with a central Cu2S2 core resulting from thio­semi­carbazone sulfur bridging. Both Cu-TCT units (TCT is the thio­phene-2-carboxaldehyde thio­semicarbazone anion) are roughly planar and are parallel to one another and perpendicular to the Cu2S2 plane.