Investigating nuclear shell structure in the vicinity of 78Ni: Low-lying excited states in the neutron-rich isotopes 80,82Zn

L

Total Synthesis of Fusaramin, Enabling Stereochemical Elucidation, Structure–Activity Relationship, and Uncovering the Hidden Antimicrobial Activity against Plant Pathogenic Fungi

Fusaramin (1) was isolated as a mitochondrial inhibitor. However, the fungal producer stops producing 1, which necessitates us to supply 1 by total synthesis. We proposed the complete stereochemical structure based on the biosynthetic pathway of sambutoxin. We have established concise and robust total synthesis of 1, enabling us to determine the complete stereochemical structure and to elucidate the structure–activity relationship, and uncover the hidden antiplant pathogenic fungal activity

Evidence for a new nuclear 'magic number' from the level structure of Ca-54

Atomic nuclei are finite quantum systems composed of two distinct types of fermion--protons and neutrons. In a manner similar to that of electrons orbiting in an atom, protons and neutrons in a nucleus form shell structures. In the case of stable, naturally occurring nuclei, large energy gaps exist between shells that fill completely when the proton or neutron number is equal to 2, 8, 20, 28, 50, 82 or 126 (ref. 1). Away from stability, however, these so-called 'magic numbers' are known to evolve in systems with a large imbalance of protons and neutrons. Although some of the standard shell closures can disappear, new ones are known to appear. Studies aiming to identify and understand such behaviour are of major importance in the field of experimental and theoretical nuclear physics. Here we report a spectroscopic study of the neutron-rich nucleus (54)Ca (a bound system composed of 20 protons and 34 neutrons) using proton knockout reactions involving fast radioactive projectiles. The results highlight the doubly magic nature of (54)Ca and provide direct experimental evidence for the onset of a sizable subshell closure at neutron number 34 in isotopes far from stability.status: publishe

Investigating the strength of the N = 34 subshell closure in 54Ca

Excited states in the exotic N = 34 isotope 54Ca have been measured for the first time via in-beam γ-ray spectroscopy with proton-knockout reactions from 55Sc and 56Ti radioactive beams on a Be reaction target at the Radioactive Isotope Beam Factory, Japan. A strong candidate for the transition from the first 2+ state to the 0+ ground state has been identified, in addition to several other weaker transitions. The structure of the N = 33 isotope 53Ca has also been investigated from the same data. Preliminary γ-ray energy spectra for 54Ca and 53Ca will be presented and the significance of the N = 34 subshell closure will be examined. Predictions of several shell-model interactions performed in the fp model space will be discussed in light of the new results.link_to_subscribed_fulltex