Observation of the negative ions:Ra−,Pa−

Abstract

BRIEF REPORTSBrief Reports are accounts of completed research which do not warrant regular articles or the priority handling giuen to Rapid Communications; howeuer, the same standards of scienttfic quality apply. (Addenda are included in Brief Reports. ) A Brief Report may be no longer than 4 printed pages and must be accompanied by an abstract Th. e same publication schedule as for regular articles is followed, and page proofs are sent to authors Observation of the negative ions: Ra, pa, and puThe negative ions of the isotopes Ra, 'Pa, and Pu have been observed by means of accelerator mass spectrometry and their properties compared with the negative ions of Th and U. The electron affinities of all these elements have been estimated to be similar and greater than 50 meV.PACS number(s): 35.10.Hn

Investigation of gas stripping at 4.1MeV for high mass negative ions

“…This is the lowest charge state which can be analysed with the existing analysing magnet (2 m radius, mass-energy product 250). Similar yields are achieved by other laboratories [3][4][5] using 5+ ions. Higher yields (10-15%) have been achieved using the 3+ charge state at 0.5-1.0 MV with lower voltage accelerators [6,7]; however it is not possible to use such low voltages on higher energy accelerators such as ANTARES.…”

“…Also, the initial ion is a negative ion, rather than the positive ions generally used in most charge state distribution experiments. Additionally, for actinides in particular, a molecular ion (such as UO À ) is injected, as this provides a higher yield from the ion source than atomic ions [3,4]. …”

Alkaline Earth Organometallics

“…), and Be-As-CBu t ¼ 102. The 9 Be NMR shift of þ14.16 ppm is highly unusual for Cp-Be-X complexes, which are usually in the À27 to À16 ppm range. The 9 Be NMR shift of þ14.16 ppm is highly unusual for Cp-Be-X complexes, which are usually in the À27 to À16 ppm range.…”

“…3(3) ; the AsBu t 2 ligand behaves as a one-electron donor ( Figure 6). A DFT study of beryllium NMR shifts predicted that Cp à BeAsBu t 2 would have a 9 Be resonance at À22.30 ppm if the Cp à ligand were strictly Z 5 , but that lower ring hapticity in solution (either a static Z 3 or an average between Z 1 and Z 5 ) would explain the observed downfield NMR shift. A DFT study of beryllium NMR shifts predicted that Cp à BeAsBu t 2 would have a 9 Be resonance at À22.30 ppm if the Cp à ligand were strictly Z 5 , but that lower ring hapticity in solution (either a static Z 3 or an average between Z 1 and Z 5 ) would explain the observed downfield NMR shift.…”

“…Organoalkaline earth gas-phase radicals MR containing the monovalent metals (M ¼ Mg-Sr; R ¼ Me, CCH, Z-Cp, Z-pyrrolate, CCCH 3 5 ) continue to be studied with both experimental and theoretical methods. 9 An IR study of the reaction of laser-ablated beryllium and magnesium atoms with acetylene in argon at 10 K indicates that BeCCH and MgCCH are products 10 ; under similar conditions in a methane/argon matrix, BeCH 3 has been identified. 9 An IR study of the reaction of laser-ablated beryllium and magnesium atoms with acetylene in argon at 10 K indicates that BeCCH and MgCCH are products 10 ; under similar conditions in a methane/argon matrix, BeCH 3 has been identified.…”