The Charge-Transfer Motif in Crystal Engineering. Self-Assembly of Acentric (Diamondoid) Networks from Halide Salts and Carbon Tetrabromide as Electron-Donor/Acceptor Synthons

Unusual strength and directionality for the charge-transfer motif (established in solution) are shown to carry over into the solid state by the facile synthesis of a series of robust crystals of the [1:1] donor/acceptor complexes of carbon tetrabromide with the electron-rich halide anions (chloride, bromide, and iodide). X-ray crystallographic analyses identify the consistent formation of diamondoid networks, the dimensionality of which is dictated by the size of the tetraalkylammonium counterion. For the tetraethylammonium bromide/carbon tetrabromide dyad, the three-dimensional (diamondoid) network consists of donor (bromide) and acceptor (CBr4) nodes alternately populated to result in the effective annihilation of centers of symmetry in agreement with the sphaleroid structural subclass. Such inherently acentric networks exhibit intensive nonlinear optical properties in which the second harmonics generation in the extended charge-transfer system is augmented by the effective electronic (HOMO−LUMO) coupling between contiguous CBr4/halide centers

Representation Theory Approach to the Polynomial Solutions of q - Difference Equations : U_q(sl(3)) and Beyond,

A new approach to the theory of polynomial solutions of q - difference equations is proposed. The approach is based on the representation theory of simple Lie algebras and their q - deformations and is presented here for U_q(sl(n)). First a q - difference realization of U_q(sl(n)) in terms of n(n-1)/2 commuting variables and depending on n-1 complex representation parameters r_i, is constructed. From this realization lowest weight modules (LWM) are obtained which are studied in detail for the case n=3 (the well known n=2 case is also recovered). All reducible LWM are found and the polynomial bases of their invariant irreducible subrepresentations are explicitly given. This also gives a classification of the quasi-exactly solvable operators in the present setting. The invariant subspaces are obtained as solutions of certain invariant q - difference equations, i.e., these are kernels of invariant q - difference operators, which are also explicitly given. Such operators were not used until now in the theory of polynomial solutions. Finally the states in all subrepresentations are depicted graphically via the so called Newton diagrams.Comment: uuencoded Z-compressed .tar file containing two ps files

Occupation probability of harmonic-oscillator quanta for microscopic cluster-model wave functions

We present a new and simple method of calculating the occupation probability of the number of total harmonic-oscillator quanta for a microscopic cluster-model wave function. Examples of applications are given to the recent calculations including $\alpha+n+n$-model for $^6$He, $\alpha+t+n+n$-model for $^9$Li, and $\alpha+\alpha+n$-model for $^9$Be as well as the classical calculations of $\alpha+p+n$-model for $^6$Li and $\alpha+\alpha+\alpha$-model for $^{12}$C. The analysis is found to be useful for quantifying the amount of excitations across the major shell as well as the degree of clustering. The origin of the antistretching effect is discussed.Comment: 9 page

HITES 2012: 'Horizons of Innovative Theories, Experiments, and Supercomputing in Nuclear Physics'

This volume contains the contributions of the speakers of an international conference in honor of Jerry Draayer's 70th birthday, entitled 'Horizons of Innovative Theories, Experiments and Supercomputing in Nuclear Physics'. The list of contributors includes not only international experts in these fields, but also many former collaborators, former graduate students, and former postdoctoral fellows of Jerry Draayer, stressing innovative theories such as special symmetries and supercomputing, both of particular interest to Jerry. The organizers of the conference intended to honor Jerry Draayer not only for his seminal contributions in these fields, but also for his administrative skills at departmental, university, national and international level. Signed: Ted Hecht University of Michigan ##IMG## [http://ej.iop.org/images/1742-6596/403/1/011001/confphoto.jpg] {Conference photograph ----- -- Scientific Advisory Committee ----- -- Ani Aprahamian -- University of Notre Dame ----- -- Baha Balantekin -- University of Wisconsin ----- -- Bruce Barrett -- University of Arizona ----- -- Umit Catalyurek -- Ohio State Unversity ----- -- David Dean -- Oak Ridge National Laboratory ----- -- Jutta Escher (Chair) -- Lawrence Livermore National Laboratory ----- -- Jorge Hirsch -- UNAM, Mexico ----- -- David Rowe -- University of Toronto ----- -- Brad Sherill & Michigan State University ----- -- Joel Tohline -- Louisiana State University ----- -- Edward Zganjar -- Lousiana State University ----- -- Organizing Committee ----- -- Jeff Blackmon -- Louisiana State University ----- -- Mark Caprio -- University of Notre Dame ----- -- Tomas Dytrych -- Louisiana State University ----- -- Ana Georgieva -- INRNE, Bulgaria ----- -- Kristina Launey (Co-chair) -- Louisiana State University ----- -- Gabriella Popa -- Ohio University Zanesville ----- -- James Vary (Co-chair) -- Iowa State University ----- -- Local Organizing Committee ----- -- Laura Linhardt -- Louisiana State University ----- -- Charlie Rasco -- Louisiana State University ----- -- Karen Richard (Coordinator) -- Louisiana State University -----Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98638/1/1742-6596_403_1_011001.pd

Rachel Carson and the rhetoric of revolution

Rachel Carson\u27s Silent Spring is justly remembered as a landmark in the history of modern environmentalism. It is, however, a more complicated text than cultural memory tends to acknowledge. Blending conservative and traditional elements with more progressive and pioneering ones, Silent Spring is marked by a complexity that extends to its reception and legacy. This article argues that-in a seeming paradox-it was the more conservative elements of Silent Spring that allowed it to be considered a revolutionary book. Carson carefully constructed her argument in ways that facilitated its initial acceptance. But those same decisions made it easier for supporters to de-emphasize its more radical implications, even as they granted it revolutionary status

Pairing and Isospin Symmetry in Proton-Rich Nuclei

Unlike their lighter counterparts, most odd-odd N=Z nuclei with mass A > 40 40 have ground states with isospin T=1, suggesting an increased role for the isovector pairing interaction. A simple SO(5) seniority-like model of this interaction reveals a striking and heretofore unnoticed interplay between like-particle and neutron-proton isovector pairing near N=Z that is reflected in the number of each kind of pair as a function of A and T. Large scale shell-model calculations exhibit the same trends, despite the simultaneous presence of isoscalar pairs, deformation, and other correlations.Comment: 8 pages + 2 postscript figures, in RevTeX. Discussion of isospin projection in HFB added. This version to appear in Phys. Lett.

Radiation sensitive area detection device and method

A radiation sensitive area detection device for use in conjunction with an X ray, ultraviolet or other radiation source is provided which comprises a phosphor containing film which releases a stored diffraction pattern image in response to incoming light or other electromagnetic wave. A light source such as a helium-neon laser, an optical fiber capable of directing light from the laser source onto the phosphor film and also capable of channelling the fluoresced light from the phosphor film to an integrating sphere which directs the light to a signal processing means including a light receiving means such as a photomultiplier tube. The signal processing means allows translation of the fluoresced light in order to detect the original pattern caused by the diffraction of the radiation by the original sample. The optical fiber is retained directly in front of the phosphor screen by a thin metal holder which moves up and down across the phosphor screen and which features a replaceable pinhole which allows easy adjustment of the resolution of the light projected onto the phosphor film. The device produces near real time images with high spatial resolution and without the distortion that accompanies prior art devices employing photomultiplier tubes. A method is also provided for carrying out radiation area detection using the device of the invention

Phase operators, phase states and vector phase states for SU(3) and SU(2,1)

This paper focuses on phase operators, phase states and vector phase states for the sl(3) Lie algebra. We introduce a one-parameter generalized oscillator algebra A(k,2) which provides a unified scheme for dealing with su(3) (for k < 0), su(2,1) (for k > 0) and h(4) x h(4) (for k = 0) symmetries. Finite- and infinite-dimensional representations of A(k,2) are constructed for k < 0 and k > 0 or = 0, respectively. Phase operators associated with A(k,2) are defined and temporally stable phase states (as well as vector phase states) are constructed as eigenstates of these operators. Finally, we discuss a relation between quantized phase states and a quadratic discrete Fourier transform and show how to use these states for constructing mutually unbiased bases