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This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes Fr202–206 performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay-spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes Fr202–206 , in addition to the identification of the low-lying states of Fr202,204 performed at the CRIS experiment.

The CRIS (Collinear Resonant Ionisation Spectroscopy) beam line is a new experimental set up at the ISOLDE facility at CERN. CRIS is being constructed for high-resolution laser spectroscopy measurements on radioactive isotopes. These measurements can be used to extract nuclear properties of isotopes far from stability. The CRIS beam line has been under construction since 2009 and testing of its constituent parts have been performed using stable and radioactive ion beams, in preparation for its first on-line run. This paper will present the current status of the CRIS experiment and highlight results from the recent tests.

A new collinear resonant ionization spectroscopy (CRIS) beam line has recently been installed at ISOLDE, CERN utilising lasers to combine collinear laser spectroscopy and resonant ionization spectroscopy. The combined technique offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing sensitive secondary experiments to be performed. A new programme aiming to use the CRIS technique for the separation of nuclear isomeric states for decay spectroscopy will commence in 2011. A decay spectroscopy station, consisting of a rotating wheel implantation system for alpha decay spectroscopy, and three high purity germanium detectors around the implantation site for gamma-ray detection, has been developed for this purpose. This paper will report the current status of the laser assisted decay spectroscopy set-up for the CRIS beam line.

The installation of an ion–beam cooler–buncher at the ISOLDE, CERN facility has provided increased sensitivity for collinear laser spectroscopy experiments. A migration of single-particle states in gallium and in copper isotopes has been investigated through extensive measurements of ground state and isomeric state hyperfine structures. Lying beyond the N 50 shell closure, 82Ga is the most exotic nucleus in the region to have been studied by optical methods, and is reported here for the first time.

The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the ionization threshold. The observed series of Rydberg states enabled the first determination of the ionization potential of the astatine atom, 9.31751(8) eV. New ab initio calculations are performed to support the experimental result. The measured value serves as a benchmark for quantum chemistry calculations of the properties of astatine as well as for the theoretical prediction of the ionization potential of superheavy element 117, the heaviest homologue of astatine. The application of astatine, one of the rarest elements on the earth, in the treatment of cancer requires a better understanding of its chemistry. Rothe et al . report the first measurement of the ionization potential of astatine, against which high-level quantum calculations are benchmarked.

The magnetic dipole moments and changes in mean-square charge radii of the neutron-rich \\(^{218m,219,229,231}\\text{Fr}\\) isotopes were measured with the newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at ISOLDE, CERN, probing the \\(7s~^{2}S_{1/2}\\) to \\(8p~^{2}P_{3/2}\\) atomic transition. The \\(\\delta\\langle r^{2}\\rangle^{A,221}\\) values for \\(^{218m,219}\\text{Fr}\\) and \\(^{229,231}\\text{Fr}\\) follow the observed increasing slope of the charge radii beyond \\(N~=~126\\). The charge radii odd-even staggering in this neutron-rich region is discussed, showing that \\(^{220}\\text{Fr}\\) has a weakly inverted odd-even staggering while \\(^{228}\\text{Fr}\\) has normal staggering. This suggests that both isotopes reside at the borders of a region of inverted staggering, which has been associated with reflection-asymmetric shapes. The \\(g(^{219}\\text{Fr}) = +0.69(1)\\) value supports a \\(\\pi 1h_{9/2}\\) shell model configuration for the ground state. The \\(g(^{229,231}\\text{Fr})\\) values support the tentative \\(I^{\\pi}(^{229,231}\\text{Fr}) = (1/2^{+})\\) spin, and point to a \\(\\pi s_{1/2}^{-1}\\) intruder ground state configuration.

This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes \\(^{202-206}\\)Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes \\(^{202-206}\\)Fr, in addition to the identification of the low-lying states of \\(^{202,204}\\)Fr performed at the CRIS experiment.

This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes $^{202-206}$Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes $^{202-206}$Fr, in addition to the identification of the low-lying states of $^{202,204}$Fr performed at the CRIS experiment.

IN nearly every country of Asia the problems which are receiving the most absorbing attention of both mission boards and of the government are educational problems. In most of these countries modern education was first provided by the missions. The few primary schools begun some sixty or seventy years ago, mainly for the children of early converts, have grown into fairly complete systems of schools--for a limited number of pupils--extending from primary grades up...

The photoactivation of electron donor–acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation of radical species. However, when it comes to aryl radical formation, this strategy remains hamstrung by the electronic properties of the aromatic radical precursors, and electron-deficient aryl halide acceptors are required. This has prevented the implementation of a general synthetic platform for aryl radical formation. Our study introduces triarylsulfonium salts as acceptors in photoactive electron donor–acceptor complexes, used in combination with catalytic amounts of newly designed amine donors. The sulfonium salt label renders inconsequential the electronic features of the aryl radical precursor and, more importantly, it is installed regioselectively in native aromatic compounds by C–H sulfenylation. Using this general, site-selective aromatic C–H functionalization approach, we developed metal-free protocols for the alkylation and cyanation of arenes, and showcased their application in both the synthesis and the late-stage modification of pharmaceuticals and agrochemicals.Photoactivation of EDA complexes was previously limited to electronically biased partners to secure productive charge-transfer interactions. Now, the participation of triarylsulfonium salts—formed by selective C–H sulfenylation—in photoactive EDA complexes with catalytic triarylamine donors provides a site-selective and metal-free strategy for the generation of aryl radicals and the formal C–H functionalization of native arenes.