Pairing and alpha-like quartet condensation in N=Z nuclei

We discuss the treatment of isovector pairing by an alpha-like quartet condensate which conserves exactly the particle number, the spin and the isospin. The results show that the quartet condensate describes accurately the isovector pairing correlations in the ground state of systems with an equal number of protons and neutronsComment: 4 pages, to appear in Journal of Physics: Conference Serie

Relativistic Mean Field Approach and the Pseudo-Spin Symmetry

Based on the Relativistic Mean Field (RMF) approach the existence of the broken pseudo-spin symmetry is investigated. Both spherical RMF and constrained deformed RMF calculations are carried out employing realistic Lagrangian parameters for spherical and for deformed sample nuclei. The quasi - degenerate pseudo-spin doublets are confirmed to exist near the fermi surface for both spherical and deformed nuclei.Comment: 9 pages RevTex, 4 p.s figures, to appear in Phys. Rev. C as R.

Physicochemical study of spiropyran-terthiophene derivatives: photochemistry and thermodynamics

The photochemistry and thermodynamics of two terthiophene (TTh) derivatives bearing benzospiropyran (BSP) moieties, 1-(3,3’’-dimethylindoline-6’-nitrobenzospiropyranyl)-2-ethyl 4,4’’-didecyloxy-2,2’:5’,2’’-terthiophene-3’-acetate (BSP-2) and 1-(3,3’’-dimethylindoline-6’-nitrobenzospiropyranyl)-2-10 ethyl 4,4’’-didecyloxy-2,2’:5’,2’’-terthiophene-3’-carboxylate (BSP-3), differing only by a single methylene spacer unit, have been studied. The kinetics of photogeneration of the equivalent merocyanine (MC) isomers (MC-2 and MC-3, respectively), the isomerisation properties of MC-2 and MC-3, and the thermodynamic parameters have been studied in cetonitrile, and compared to the parent, non-TThfunctionalised, benzospiropyran derivative, BSP-1. Despite the close structural similarity of BSP-2 and 15 BSP-3, their physicochemical properties were found to differ significantly; examples include activation energies (Ea(MC-2) = 75.05 KJ mol-1, Ea(MC-3) = 100.39 kJ mol-1) and entropies of activation (S‡ MC-2 = - 43.38 J K-1 mol-1, S‡ MC-3 = 37.78 J K-1 mol-1) for the thermal relaxation from MC to BSP, with the MC-3 value much closer to the unmodified MC-1 value (46.48 J K -1 mol-1) for this latter quantity. The thermal relaxation kinetics and solvatochromic behaviour of the derivatives in a range of solvents of 20 differing polarity (ethanol, dichloromethane, acetone, toluene and diethyl ether) are also presented. Differences in the estimated values of these thermodynamic and kinetic parameters are discussed with reference to the molecular structure of the derivatives

Nuclear Breathing Mode in the Relativistic Mean Field Theory

The breathing-mode giant monopole resonance is studied within the framework of the relativistic mean-field (RMF) theory. Using a broad range of parameter sets, an analysis of constrained incompressibility and excitation energy of isoscalar monopole states in finite nuclei is performed. It is shown that the non-linear scalar self-interaction and the resulting surface properties influence the breathing-mode considerably. It is observed that dynamical surface properties respond differently in the RMF theory than in the Skyrme approach. A comparison is made with the incompressibility derived from the semi-infinite nuclear matter and with constrained nonrelativistic Skyrme Hartree-Fock calculaions.Comment: Latex (12 pages) and 3 figures (available upon request) J. Phys. G (in press

Temperature induced shell effects in deformed nuclei

The thermal evolution of the shell correction energy is investigated for deformed nuclei using Strutinsky prescription in a self-consistent relativistic mean-field framework. For temperature independent single-particle states corresponding to either spherical or deformed nuclear shapes, the shell correction energy $\Delta_{sc}$ steadily washes out with temperature. However, for states pertaining to the self-consistent thermally evolving shapes of deformed nuclei, the dual role played by the single-particle occupancies in diluting the fluctuation effects from the single-particle spectra and in driving the system towards a smaller deformation is crucial in determining $\Delta_{sc}$ at moderate temperatures. In rare earth nuclei, it is found that $\Delta_{sc}$ builds up strongly around the shape transition temperature; for lighter deformed nuclei like $^{64}Zn$ and $^{66}Zn$, this is relatively less prominent.Comment: 6 pages revtex file + 4 ps files for figures, Phys. Rev. C (in press

Alpha-decay chains of 173288115^{288}_{173}115 and 172287115^{287}_{172}115 in the Relativistic Mean Field theory

In the recent experiments designed to synthesize the element 115 in the $^{243}$Am+$^{48}$Ca reaction at Dubna in Russia, three similar decay chains consisting of five consecutive $\alpha$-decays, and another different decay chain of four consecutive $\alpha$-decays are detected, and the decay properties of these synthesized nuclei are claimed to be consistent with consecutive $\alpha$-decays originating from the parent isotopes of the new element 115, $^{288}115$ and $^{287}115$, respectively\cite{ogan.03}. Here in the present work, the recently developed deformed RMF+BCS method with a density-independent delta-function interaction in the pairing channel is applied to the analysis of these newly synthesized superheavy nuclei $^{288}115$, $^{287}115$, and their $\alpha$-decay daughter nuclei. The calculated $\alpha$-decay energies and half-lives agree well with the experimental values and with those of the macroscopic-microscopic FRDM+FY and YPE+WS models. In the mean field Lagrangian, the TMA parameter set is used. Particular emphasis is paid on the influence to both the ground-state properties and energy surfaces introduced by different treatments of pairing. Two different effective interactions in the particle-particle channel, i.e., the constant pairing and the density-independent delta-function interaction, together with the blocking effect are discussed in detail.Comment: 17 pages, 5 figure

The contribution of non-CO2 greenhouse gas mitigation to achieving long-term temperature goals

In the latest (fifth) assessment from the Intergovernmental Panel on Climate Change (IPCC) non-CO2 emssions accounted for 28% of total GHG emissions in 2010, when measured on the basis of their global warming potential (relative to CO2) over a 100-year and nitrous oxide (N2O) accounting for about half of all non-CO2 GHGs. With population and incomes increasing, especially in emerging economies, these emissions could grow significantly in the future. Other major sources of non-CO2 GHGs are fugitive CH4 from the extraction and distribution of fossil fuels, N2O from industrial production of nitric and adipic acid, as well as fluorinated gases (F-gases) from a range of industrial manufacturing and product uses. This paper analyses the emissions and cost impacts of mitigation of non-CO2 greenhouse gases (GHGs) at a global level, in scenarios which are focused on meeting a range of long-term temperature goals (LTTGs). The paper demonstrates how an integrated assessment model (TIAM-Grantham) representing CO2 emissions (and their mitigation) from the fossil fuel combustion and industrial sectors is coupled with a model covering non-CO2 emissions (GAINS) in order to provide a complete picture of GHG emissions in a reference scenario in which there is no mitigation of either CO2 or non-CO2 gases, as well as in scenarios in which both CO2 and non-CO2 gases are mitigated in order to achieve different LTTGs

Generalized seniority scheme in light Sn isotopes

The yrast generalized seniority states are compared with the corresponding shell model states for the case of the Sn isotopes $^{104-112}$Sn. For most of the cases the energies agree within 100 keV and the overlaps of the wave functions are greater than 0.7.Comment: 8 pages, revtex. Submitted to Phys. Rev.

Assessing the challenges of global long-term mitigation scenarios

The implications of global mitigation to achieve different long-term temperature goals (LTTGs) can be investigated in integrated assessment models (IAMs), which provide a large number of outputs including technology deployment levels, economic costs, carbon prices, annual rates of decarbonisation, degree of global net negative emissions required, as well as utilisation levels for fossil fuel plants. All of these factors can be considered in detail when judging the real-world feasibility of the mitigation scenarios produced by these models. This study presents a model inter-comparison of three widely used IAMs (TIAM, MESSAGE and WITCH) to analyse multiple mitigation scenarios exploring a range of LTTGs and a range of constraints, including delayed mitigation action, limited end-use electrification and delayed deployment of carbon capture technologies. The scenario outputs across the three models are examined and discussed and a matrix of the different factors concerning scenario feasibility is presented

Magnetic moments of 33^{33}Mg in time-odd relativistic mean field approach

The configuration-fixed deformation constrained relativistic mean field approach with time-odd component has been applied to investigate the ground-state properties of $^{33}$Mg with effective interaction PK1. The ground state of $^{33}$Mg has been found to be prolate deformed, $\beta_2=0.23$, with the odd neutron in $1/2[330]$ orbital and the energy -251.85 MeV which is close to the data -252.06 MeV. The magnetic moment $- 0.9134 \mu_\mathrm{N}$ is obtained with the effective electromagnetic current which well reproduces the data $- 0.7456 \mu_\mathrm{N}$ self-consistently without introducing any parameter. The energy splittings of time reversal conjugate states, the neutron current, the energy contribution from the nuclear magnetic potential, and the effect of core polarization are discussed in detail.Comment: 13 pages, 4 figure