Particle plus octupoleM2/E3 isomers and high-spin particle-hole states in147Tb and148Tb

The level structures of theN=82 andN=83 nuclei¹⁴⁷Tb and¹⁴⁸Tb have been studied by means of (α, 8n) and (α,7n) reactions induced by 68 to 110 MeVα particle bombardments of¹⁵¹Eu targets. In-beam conversion electron measurements have established that isomers withT _1/2=4.8(6)ns in¹⁴⁷Tb andT _1/2=22(1)ns in¹⁴⁸Tb decay byM2+E3 transitions to the ground states. The measuredB(E3) values show that the isomeric states arise from the coupling of the valence nucleon(s) to the¹⁴⁶Gd core octupole. Particlephonon coupling in these nuclei and in the one-neutron nucleus¹⁴⁷Gd is discussed and compared with well known cases involving the²⁰⁸Pb core. The higher lying yrast states in the two Tb nuclei are described as shell-model particle-hole excitations using empirical single particle energies and nucleon-nucleon interactions.     

Few-valence-particle excitations around doubly magic 132Sn

Prompt γ-ray cascades in neutron-rich nuclei around doubly-magic ¹³²Sn have been studied using a ²⁴⁸Cm fission source. Yrast states located in the N = 82 isotones ¹³⁴Te and ¹³⁵I are interpreted as valence proton and neutron particle-hole core excitations with the help of shell model calculations employing empirical nucleon-nucleon interactions from both ¹³²Sn and ²⁰⁸Pb regions.     

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

Pigments from red coral (Corallium rubrum) and African snail (Helixia aspersa) shell were studied non‐invasively using Raman spectroscopy with 1064‐nm laser beam. The two observed bands because of organic pigments confined in biomineralized CaCO₃ matrix at about 1500 and 1100 cm⁻¹ were assigned to ν(CC) and ν(C―C), respectively. Both signals originate from polyene(s) of largely unknown structure, containing several conjugated CC bonds. The small peak at 1016 cm⁻¹ in the Raman spectrum of coral pigment was assigned to in‐plane ―CH₃ rocking or structural deformation of polyene chain because of spatial confinement in the mineral matrix. The organic pigments in red coral and snail shell were present in inorganic matrix containing aragonite (shell) and calcite (coral). In addition, using Raman spectroscopy, it was observed that aragonite was replaced by calcite as result of healing damaged parts of snail shell. This is an important finding which indicates a great potential of nondestructive Raman spectroscopy instead of X‐ray technique, as a diagnostic tool in environmental studies. To support analysis of the observed Raman spectra detailed calculations using density functional theory (DFT with B3LYP and BLYP density functionals) on structure and vibrations of model all‐trans polyenes were undertaken. DFT calculated CC and C―C stretching frequencies for all‐trans polyenes containing from 2 to 14 CC units were compared with the observed ν(CC) and ν(C―C) band positions of the studied coral and shell. Individual correction factors were used to better match theoretical wavenumbers with observed band positions in red coral and African snail. It was concluded that all‐trans polyene pigments of red coral and dark parts of African snail shell contain 11–12 and 14 CC double bond units, respectively. However, Raman spectroscopy cannot produce any clear information on the presence and nature of the end‐chain substituents in the studied pigments. Copyright © 2016 John Wiley & Sons, Ltd.     

Die empfindliche Serienbestimmung von Radiokohlenstoff mit einem Gaszählrohr

Zusammenfassung Die Leistungsfähigkeit verschiedener Methoden zur empfindlichen Serienmessung von Radiokohlenstoff wird verglichen. Eine Methode wird beschrieben, bei der der Kohlenstoff in Form von ungereinigtem, zusatzfreiem Kohlendioxyd zum Füllen eines Zählrohres verwendet wird. Der Fülldruck kann 1 Atmosphäre und mehr betragen. Fast steigungsfreie Konstanzbereiche von einer Länge bis zu 1200 V werden erhalten. Ein Gehalt des Gases an Wasserdampf schadet nicht, ein Gehalt an Luft erst bei einem Partialdruck von mehreren Millimetern Quecksilber.

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Summary A comparison was made of the efficiency of various methods for the sensitive serial measurements of radio carbon. A method is described in which the carbon used for filling a counting tube was in the form of nonpurified, additive-free carbon dioxide. The filling pressure may be 1 atmosphere and more. Plateaus practically free from increases were obtained from a length up to 1200 volts. No harm results if the gas contains water vapor, and air does not interfere until its partial pressure exceeds several millimeters of mercury.

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Résumé On compare la valeur de plusieurs méthodes en vue de la mesure en série du radiocarbone de façon sensible. On décrit une méthode suivant laquelle on remplit le tube-compteur avec du gaz carbonique non purifié et exempt de toute addition. La pression du remplissage peut s'élever jusqu'à 1 atmosphère et plus. On obtient des valeurs constantes qui n'augmentent pour ainsi dire pas, jusqu'à 1200 volts. La présence de vapeur d'eau dans le gaz ne gêne pas, celle de l'air non plus, jusqu'à une pression partielle de plusieurs millimètres de mercure.

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Herrn Prof. Dr.-Ing.F. Feigl in Verehrung zum 70. Geburtstag gewidmet.

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In Dankbarkeit gedenktE. B. des unermüdlichen Interesses, das der damalige DozentFeigl den Anfängern in seinem Saale entgegenbrachte, und des Enthusiasmus, den er auf sie übertrug.     

The decay of the 560 ns Isomer at 8.6 MeV in 64 147 Gd83

In (α,xn) and (¹²C, 5n) in-beamγ-ray experiments with pulsed beams the decay of the 560 ns high-spin isomer in¹⁴⁷Gd has been investigated. Extensive coincidence measurements identified in the isomeric decay more than eightyγ-rays which almost all were placed in the level scheme. Of crucial importance for establishing the highly complex decay was the comparison of data from the different reactions and the identification of transitions which bypass the 27 ns isomer at 3.58 MeV. Our data determine the excitation of the 560 ns isomer as 8.588 MeV and suggest 47/2 as its most probable spin.     

Magnetic moments of the 10− isomeric states in 202Bi and 204Bi

The g-factors of the 10^? isomeric states in ²⁰²Bi and ²⁰⁴Bi have been measured by the method of in-beam TDPAD. The experimental values $\text{g = 0.243(14)}\text{for}{}^{202}\text{Bi}\text{and}\text{g = 0.236(23)}\text{for}{}^{204}\text{Bi}$ confirm the previously suggested shell-model configuration.