NeXSPheRIO results on elliptic flow and directed flow for Au+Au and Cu+Cu collisions at RHIC

Hydrodynamics has been rather successful at describing results obtained in relativistic nuclear collisions at RHIC. Here we show results obtained with NeXSPheRIO on Au+Au collisions and the less studied Cu+Cu collisions. We study elliptic flow and its connection with eccentricity suggested by PHOBOS, as well as present elliptic flow fluctuations. We also show results for directed flow and compare with PHOBOS and STAR data.     

Construction of diffractive amplitudes

Starting from a simple parametrization of production amplitudes an explicit construction of the diffractive elastic amplitude through multiparticle unitarity is given. It is shown that the phase cancellation effect is essential in order to obtain an elastic amplitude which display a diffractive peak in qualitative agreement with the data.     

Production rates of excited fragment isotopes from the36Ar+Ag reaction at 35 MeV/nucleon

Previous studies showed that the binding energy plays a systematic and important role in the production of ground-state fragments in intermediate energy, heavy ion reactions. The production rates were measured as a function of fragment kinetic energy at angles of 15°, 30°, 45° and 60° for excited fragments of⁷Li,⁸Li,¹¹Be and¹²B. Using a thermal model the total production of neutron unbound excited states was determined, and it was found that their production rates correspond to the previous systematic behaviour using the binding energies corrected by the excitation energies.     

Particle emission in the hydrodynamical description of relativistic nuclear collisions

The usual particle emission scenario used in hydrodynamics presupposes that particles instantaneously stop interacting once they reach some three dimensional surface. Here we set up a new formalism to study continuous particle emission during the whole expansion of thermalized matter. This scenario changes completely the usual interpretation of transverse momentum spectra, may help to understand data on strange particle ratios and is possible to include in hydrodynamical codes.     

Molecular structures and hypochromism of two purinophanes

The structures of purinophane 1 and its higher homolog 2 were determined by X-ray crystallographic analysis. Hypochroism of 1 and 2 in various media reported.     

OPTICAL ABSORPTION AND ELECTRON SPIN RESONANCE SPECTRA OF CATION RADICALS OF DIMERIC CHLOROPHYLL a IN LOW-TEMPERATURE MATRICES

Abstract— A chlorophyll (Chl) a solution in 3-methylpentane at 77 K exhibits an absorption spectrum with a distinct peak at 706 nm in the red-band region. The formation of the 706 nm absorbing species (S706) was reversible with respect to temperature change; no chemical change was observed. γ-Irradiation of the rigid 3-methylpentane solution at 77 K yields an absorption spectrum which can be ascribed to S706⁺ and S706⁻. When carbon tetrachloride, an electron scavenger, was added to the solution, the absorption of S706⁺ survived, which has peaks at 850 and 956 nm. It is assumed that the S706 is hydrogen-bonded dimeric Chi a , which may be regarded as a model of P700 in photosynthesis. Cation radicals of monomeric Chi a were formed in a γ-irradiated sec -butyl chloride solution at 77 K, and an absorption spectrum with peaks at 730 and 813 nm was recorded. ESR spectra of the cation radicals of S706 and monomeric Chi a are of a similar shape but their linewidths are 7.5 and 11.0 Gauss, respectively. The linewidth narrowing observed for S706⁺ is clear evidence for the assumption that S706 is dimeric Chi a. Comparison was made of the absorption spectrum of S706⁺ with the light-induced spectrum of P700 reported earlier.     

Confirmation of the crystal structure of poly(p‐phenylene benzobisoxazole) by the X‐ray structure analysis of model compounds and the energy calculation

To check the previously proposed crystal structure of poly(p‐phenylene benzobisoxazole) [PBO], we performed an X‐ray structure analysis for single crystals of low molecular weight model compounds with the following chemical formulas: Both of these two model compounds show essentially the same molecular and subcell structures as those of PBO: the molecular chains take an almost perfect planar conformation and are packed together with a relative height between the adjacent chains of about 3 Å along the chain axis, although for the polymer the chains are shifted by the same value but in a disordered mode with respect to the direction of the shift (upward or downward), different from the regular packing in model compounds. These structural features are reproduced well with energy calculations. Structural ordering in PBO fibers caused by heat treatment at high temperatures, as clarified by X‐ray diffraction measurement, are interpreted on the basis of the energy calculations. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1296–1311, 2001