New approach of fragment charge correlations in Xe+Sn central collisions

A previous analysis of the charge (Z) correlations in the ΔZ−Z plane for ¹²⁹Xe+^natSn central collisions at 32 MeV/n has shown an enhancement in the production of equally sized fragments (low ΔZ) which was interpreted as an evidence for spinodal decomposition. However, the signal is weak and rises the question of the estimation of the uncorrelated yield. After a critical analysis of its robustness, we propose in this paper a new technique to build the uncorrelated yield in the charge correlation function. The application of this method to ¹²⁹Xe+^natSn central collision data at 32, 39, 45 and 50 MeV/n does not show any particular enhancement of the correlation function in any ΔZ bin.     

A theoretical method to determine atomic pseudopotentials for electronic structure calculations of molecules and solids

The characteristic features of model potentials, effective potentials and pseudopotentials are carefully investigated. Then we justify our choice to work only with hermitian pseudopotential operators, and we develop a general non-empirical method to determine atomic pseudopotentials. In view of their numerical use for molecular calculations, these pseudopotentials are cast into semi-local forms, and their parameters are obtained by a least-squares process; tables of parameter values are given for the two first rows of the periodic system.     

The Ruderman-Kittel-Kasuya-Yosida interaction in amorphous La80Au20 alloys with dilute Gd impurities

From magnetization measurements on some amorphous dilute La_80?xGd_xAu₂₀ alloys with x ? 1 we have shown that the magnetic behavior follows the scaling laws of a spin-glass system, characteristic of the 1/r³ dependence of the pairwise interaction. We have also determined the strength of the Ruderman-Kittel-Kasuya-Yosida interaction V(r) = (V₀cos 2k_Fr)/r³, to be V₀ = 0.20 × 10^?37 ergcm³. The corresponding value of the s-f exchange integral is |J_sf| = 0.14 eV, which is compared with values determined from other experiments.     

Paramagnetic complexes of platinum and palladium with acetamide

Summary Direct reaction of K₂MCl₄ (M=Pt or Pd) with acetamide leads reproducibly to complexes which can be formulated as [Pt(C₂H₄ON)₂Cl]_n and Pd₄(C₂H₄ON)₇(OH)₂. Analytical and spectroscopic (i.r., n.m.r. and e.p.r.) data support the existence of polynuclear structures involving bridging ligands and partially oxidized metal centres.     

Réseaux polyuréthanne: étude théorique et expérimentale de leurs propriétés élastiques

Physical properties-structure relationships have been investigated for polyurethane networks. Sol fraction, swelling and elastic modulus have been measured. Structural parameters derived from these measurements have been compared with those from theoretical models. As a result, the behaviour of these these networks appears to lie between those of phantom and affine network models.     

Etude par resonance quadripolaire des noyaux 63-Cu et 75-As de complexes tetrameres de la triethylarsine avec des halogenures de cuivre(I)

63-Cu and 75-As quadrupole resonance results have been obtained for the tetrameric triethylarsine copper(I) halides (Cl, Br and I). Unusual behaviours of the temperature dependence of the 63-Cu and 75-As quadrupole resonance lines have been observed simultaneously. Between 77 and 300 K, the chlorine derivative undergoes two structural phase changes at 93 and 173 K, while phase transformations occur at 152 and 86 K respectively for the bromine and iodine derivatives.     

Rechenautomat 704 IBM

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