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Title: Linear-chain structure of three {alpha} clusters in {sup 13}C

Abstract

We investigate a linear-chain configuration of three {alpha} clusters with a neutron in {sup 13}C. To characterize this configuration, an operator P is introduced, which is the sum of parity inversion operators for each proton. The states with positive expectation values for this operator are found to form a rotational band structure, and the moment of inertia agrees well with the experimentally suggested value. Allowing a small bending angle stabilizes the linear-chain configuration of three {alpha} clusters with a valence neutron, which is a hyper-deformed state.

Authors:
 [1];  [2];  [1];  [3];  [4]
  1. Hahn-Meitner-Institut Berlin, D-14109 Berlin (Germany)
  2. (Japan)
  3. (Germany)
  4. Information Initiative Center, Hokkaido University, 060-0811 Sapporo (Japan)
Publication Date:
OSTI Identifier:
20864251
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 74; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.74.067304; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA PARTICLES; CARBON 13; CLUSTER MODEL; CONFIGURATION; MOMENT OF INERTIA; NEUTRONS; NUCLEAR STRUCTURE; PARITY; PROTONS; ROTATIONAL STATES; SUPERDEFORMED NUCLEI; VALENCE

Citation Formats

Itagaki, N., Department of Physics, University of Tokyo, Hongo, 113-0033 Tokyo, Oertzen, W. von, Freie Universitaet Berlin, Fachbereich Physik, D-14195 Berlin, and Okabe, S.. Linear-chain structure of three {alpha} clusters in {sup 13}C. United States: N. p., 2006. Web. doi:10.1103/PHYSREVC.74.067304.
Itagaki, N., Department of Physics, University of Tokyo, Hongo, 113-0033 Tokyo, Oertzen, W. von, Freie Universitaet Berlin, Fachbereich Physik, D-14195 Berlin, & Okabe, S.. Linear-chain structure of three {alpha} clusters in {sup 13}C. United States. doi:10.1103/PHYSREVC.74.067304.
Itagaki, N., Department of Physics, University of Tokyo, Hongo, 113-0033 Tokyo, Oertzen, W. von, Freie Universitaet Berlin, Fachbereich Physik, D-14195 Berlin, and Okabe, S.. Fri . "Linear-chain structure of three {alpha} clusters in {sup 13}C". United States. doi:10.1103/PHYSREVC.74.067304.
@article{osti_20864251,
title = {Linear-chain structure of three {alpha} clusters in {sup 13}C},
author = {Itagaki, N. and Department of Physics, University of Tokyo, Hongo, 113-0033 Tokyo and Oertzen, W. von and Freie Universitaet Berlin, Fachbereich Physik, D-14195 Berlin and Okabe, S.},
abstractNote = {We investigate a linear-chain configuration of three {alpha} clusters with a neutron in {sup 13}C. To characterize this configuration, an operator P is introduced, which is the sum of parity inversion operators for each proton. The states with positive expectation values for this operator are found to form a rotational band structure, and the moment of inertia agrees well with the experimentally suggested value. Allowing a small bending angle stabilizes the linear-chain configuration of three {alpha} clusters with a valence neutron, which is a hyper-deformed state.},
doi = {10.1103/PHYSREVC.74.067304},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 74,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}
  • The stability of the three-{alpha} linear-chain structure of {sup 13}C has been investigated with a microscopic 3{alpha}+n model. We have found two excited rotational bands that have developed a three-{alpha} cluster structure in {sup 13}C. The lower band built on 3/2{sub 2}{sup -} state at 11.4 MeV has the bent three-{alpha} linear-chain structure, and this structure is stable against the bending motion of three-{alpha} clusters.
  • Redox-condensation reactions involving (PPN)/sub 2/(Fe/sub 3/(CO)/sub 9/(CCO)) and electrophilic transition-metal reagents lead to (PPN)/sub 2/(MFe/sub 3/(CO)/sub 13/C) (M = Cr, W), (PPN)/sub 2/(Cr/sub 2/Fe/sub 3/(CO)/sub 16/C), Rh/sub 2/Fe/sub 3/(CO)/sub 14/C, and (PPN)(Rh/sub 3/Fe/sub 3/(CO)/sub 15/C). Variable-temperature /sup 13/C NMR spectroscopy was employed to assign the structures of the tetranuclear clusters and Rh/sub 2/Fe/sup 3/(CO)/sub 14/C in solution. An improved synthesis of (PPN)(RhFe/sub 3/(CO)/sub 12/C) and more complete variable-temperature (ca. -130 to +20 /sup 0/C) /sup 13/C NMR spectra of this cluster and (PPN)(MnFe/sub 3/(CO)/sub 13/C) are discussed. All of the tetranuclear clusters are assigned butterfly metal geometries will the heterometalsmore » located at hinge sites. Attempts to prepare iron-molybdenum carbide clusters are discussed. The structure of (PPN)(Rh/sub 3/Fe/sub 3/(CO)/sub 15/C) was determined by a single-crystal x-ray diffraction study and was found to consist of a trigonal-antiprismatic metal array with the carbide ligand within the metal polyhedron. The iron atoms define one of the trigonal faces and the rhodium atoms define the other. Crystal data for (PPN)(Rh/sub 3/Fe/sub 3/(CO)/sub 15/C): monoclinic, space group P2/sub 1//n, a = 16.220 (6) A, b = 9.282 (3) A, c = 35.17 (3) A, ..beta.. = 94.84 (5)/sup 0/, Z = 4. 28 references, 5 figures, 6 tables.« less
  • The assignment of the aliphatic {sup 1}H and {sup 13}C resonances of IL-1{beta}, a protein of 153 residues and molecular mass 17.4 kDa, is presented by use of a number of novel three-dimensional (3D) heteronuclear NMR experiments which rely on large heteronuclear one-bond J couplings to transfer magnetization and establish through-bond connectivities. These 3D NMR experiments circumvent problems traditionally associated with the application of conventional 2D {sup 1}H-{sup 1}H correlation experiments to proteins of this size, in particular the extensive chemical shift overlap which precludes the interpretation of the spectra and the reduced sensitivity arising from {sup 1}H line widthsmore » that are often significantly larger than the {sup 1}H-{sup 1}H J couplings. The assignment proceeds in two stages. In the first step the {sup 13}C{alpha} chemical shifts are correlated with the NH and {sup 15}N chemical shifts by a 3D triple-resonance NH-{sup 15}N-{sup 13}C{alpha} (HNCA) correlation experiment which reveals both intraresidue NH(i)-{sup 15}N(i)-{sup 13}C{alpha}(i) and some weaker interresidue NH(i)-{sup 15}N(i)-C{alpha}(i-1) correlations, the former via intraresidue one-bond {sup 1}J{sub NC{alpha}} and the latter via interresidue two-bond {sup 2}H{sub NC{alpha}} couplings. The second step involves the identification of side-chain spin systems by 3D {sup 1}H-{sup 13}C-{sup 13}C-{sup 1}H correlated (HCCH-COSY) and 3D {sup 1}H-{sup 13}C-{sup 13}C-{sup 1}H total correlated (HCCH-TOCSY) spectroscopy, the latter making use of isotropic mixing of {sup 13}C magnetization to obtain relayed connectivities along the side chains. The authors were able to obtain complete {sup 1}H and {sup 13}C side-chain assignments for all residues, with the exception of 4 (out of a total of 15) lysine residues for which partial assignments were obtained.« less