Yrast excitations in129Te

Using an 11.4MeV/u¹³⁶Xe beam of the UNILAC accelerator of GSI and a^natW target, A=184 isobars were produced and separated by using an on-line mass separator. A new isomeric state was found in¹⁸⁴Hf. This state decays with a half-life of 48(10) s and emits three -rays of 73, 482, and 555 keV as well as lower-lying cascade transitions. The hindrance of the 73 keV-E1 transition with K=8 is compared with those of other even-even hafnium isotopes. The half-life of¹⁸⁴Lu was estimated to be between 15 and 25s.     

Solvent-generated HPLC systems with β-cyclodextrin derivatives as chiral additives

It is shown that enantioselective solvent-generated liquid-liquid and liquid-solid Chromatographic systems with -cyclodextrin derivatives can be realized. The liquid-liquid systems are based on ternary solvent systems of limited miscibility, containing chiral additives; the chiral stationary phase is spontaneously generated on the porous microparticulate silica used as a solid support. In the solvent-generated adsorption systems a very small proportion of -cyclodextrin derivatives is added to the mobile phase. These components act as column activators, since they are strongly adsorbed on the RP solid support where they form new stereoselective adsorption sites. It is demonstrated that dynamically generated systems with -cyclodextrin derivatives as chiral agents are powerful and versatile tools for enantioseparation of different types of compounds. This technique creates not only a new type of selectivity but also leads to very stable and reproducible Chromatographic columns.Dedicated to Professor J. F. K. Huber on the occasion of his 65th birthday     

Protective effects of vitamin E against CCl<Subscript>4</Subscript>-induced hepatotoxicity in rabbits

The influence of CCl₄ on the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), the value of the total antioxidant status (TAS), and the concentration of malonic dialdehyde (MDA) and glutathione (GSH) was monitored in plasma or whole blood of rabbits. The administration of CCl₄ caused the increase of the SOD activity to approximately 150 % and the decrease in the activity of GPx and GR by about 50 %. These changes were accompanied with the increase in TAS value and MDA concentration and the decrease of GSH concentration. The effect of CCl₄ was suppressed by the previous 7 days lasting or simultaneous administration of vitamin E. Oxidative stress caused by CCl₄ was accompanied by the development of reactive oxygen forms, especially superoxide radical anion.     

Applicability of medium-size basis sets in calculations of molecular dynamic polarisabilities

Static and dynamic average polarisabilities and polarisability anisotropies of seven linear non-polar and polar molecules are calculated within the CCS, CC2, and CC3 approximations using a range of medium-sized basis sets: the polarised LPol-n (n = ds, dl, fs, fl), the aug-pc-n (n = 1, 2), the def2-SVPD, and -TZVPD basis sets. Reference values are obtained using a hierarchy of Dunning's (d-)aug-cc-pVXZ (X = D, T, Q, 5) basis sets. The results are discussed together with the available CCSD values in terms of basis set and correlation method errors, and their ratio. Detailed analysis shows that already the def2-SVPD basis set can be used in CCS polarisability calculations. When affordable, the slightly larger aug-pc-1 basis set is recommended, as it leads to significant reduction of basis set error. The def2-TZVPD, LPol-ds, and aug-pc-2 basis sets are optimal choice within the CC2 approximation, with the latter allowing to approach the CC2 basis set limit. The LPol-ds, -dl, and def2-TZVPD sets outperform the aug-cc-pVTZ set in average polarisability CCSD calculations, with the def2-TZVPD being competitive to other reduced-size sets also in determination of polarisability anisotropy. The aug-pc-2 basis is a particularly attractive choice for CCSD, giving the accuracy of aug-cc-pVQZ at a significantly reduced computational cost. The polarisability anisotropy is shown to be more computationally demanding than the average polarisability, in particular with respect to the accuracy of the correlation method and an accurate evaluation of this property requires at least the CCSD model.     

Hard-to-reach nuclei studied with deep-inelastic heavy-ion reactions

Spectroscopic studies performed with deep-inelastic heavy-ion reactions are reviewed for two regions of neutron-rich nuclei. The identification of isomers in nearly complete series of Sn isotopes and the resulting systematic of B(E2) values for isomeric transitions is presented and followed by the discussion of shell model states studied in neutron-rich Te isotopes including the new four neutron-hole isomers identified in ¹³⁰Te. Yrast spectroscopy studies of nuclei from the doubly magic ²⁰⁸Pb region are described by outlining the highest spin states observed in the ²⁰⁸Pb core nucleus. The E3 transitions observed abundantly in yrast decays are discussed within the framework of particle-octupole vibration coupling and the validity of a simple rule connecting energy shifts of octupole states built on one-particle states with the ones observed for two-particle states is demonstrated.Received: 15 January 2003, Published online: 23 March 2004PACS: 21.60.Cs Shell model - 23.20.Lv transitions and level energies - 27.60. + j - 27.80. + w      

Charge density: A probe for the nuclear interaction in microscopic transport models

The transport properties of the ³⁶Ar +⁵⁸Ni system at measured with the INDRA array, are studied within the BNV kinetic equation. A general protocol of comparison between the N-body experimental fragment information and the one-body distribution function is developed using global variables, with a special focus on charge density. This procedure avoids any definition of sources and any use of an afterburner in the simulation. We shall discuss the feasibility of such an approach and the distortions induced by the finite detection efficiency and the completeness requirements of the data selection. The sensitivity of the different global observables to the macroscopic parameters of the effective nuclear interaction will be studied in detail.Received: 21 January 2003, Published online: 5 August 2003PACS: 25.70.-z Low and intermediate energy heavy-ion reactions - 24.10.-i Nuclear reaction models and methodsN. Le Neindre: Permanent address: Institut de Physique Nuclaire, IN2P3-CNRS, F-91406 Orsay cedex, France.     

Percolation properties of the antiferromagnetic Blume-Capel model in the presence of a magnetic field

The problem of order-order and order-disorder transitions in the system described by the 2D antiferromagnetic Blume-Capel model in the presence of a magnetic field is studied by the Wang and Landau flat-histogram simulation method and by the classical Monte Carlo. Anomalous thermodynamic characteristics in low temperatures indicate different type orderings in finite temperatures. The existence of pure antiferromagnetic phases as well as mixed state is shown by detailed phenomenological analysis of the system. The border lines on the phase diagram between various orderings are determined by the complementary microscopic study of the percolation problem for c(2×2) elementary structures of antiferromagnetic ordered phases. This new approach has also shown a full agreement between the percolation threshold for the cluster of mixed phase and the critical temperature of the ordered system.     

FT-FIR-spectrum and the ground state constants of D2CO

The ground state spectrum of the formaldehyde D₂¹³CO molecule in the range from 25 to 360 cm⁻¹ has been recorded by a Fourier transform infrared spectrometer. The quantum number limits of the assigned transitions are J = 6-54 and K_a = 0-16. The data was fitted into Watson’s A- and S-reduced Hamiltonians in I^r-representation up to eighth order. The determinable constants calculated from both reductions are compared. The standard deviation of the far infrared data is 3.0 MHz. The spectroscopic constants are also calculated to high accuracy at the CCSD(T)/cc-pVQZ level of ab initio theory and agree well with the experimental ones.     

Charge orderings in the atomic limit of the extended Hubbard model

The extended Hubbard model in the atomic limit (AL-EHM) on a square lattice with periodic boundary conditions is studied with use of the Monte Carlo (MC) method. Within the grand canonical ensemble the phase and order-order boundaries for charge orderings are obtained. The phase diagrams include three types of charge ordered phases and the nonordered phase. The system exhibits very rich structure and shows unusual multicritical behavior. In the limiting case of t_ij=0, the EHM is equivalent to the pseudospin model with single-ion anisotropy , exchange interaction W in an effective magnetic field . This classical spin model is analyzed using the MC method for the canonical ensemble. The phase diagram is compared with the known results for the Blume-Capel model.