Yrast and near-yrast states above the known 25/2+ isomer in 207At are established for the first time. The level scheme is extended up to 47/2ℏ and 6.5 MeV with the addition of about 60 new γ-ray transitions. The half-life of the 25/2+ isomer is revisited and a value of T1/2 = 107.5(9) ns is deduced. Evidence of a hitherto unobserved 29/2+ isomer in 207At is presented. A systematic study of B(E3) values for the transitions de-exciting the 29/2+ isomer in the neighboring odd-A At isotopes suggests a half-life in the 2−4.5 μs range for this state in 207At. The experimental results are compared with large-scale shell-model calculations performed using the KHM3Y effective interaction in the Z = 50−126, N = 82−184 model space and an overall good agreement is noted between the theory and the experiment. A qualitative comparison of the excited states and the isomers with analogous states in neighboring nuclei provides further insight into the structure of 207At.
@article{arxiv.2211.02406,
title = {High-spin spectroscopy in $^{207}$At: Evidence of a 29/2$^{+}$ isomeric state},
author = {Khamosh Yadav and A. Y. Deo and Madhu and Dhananjaya Sahoo and P. C. Srivastava and Saket Suman and S. K. Tandel and A. Sharma and I. Ahmed and K. Katre and K. Rojeeta Devi and Sunil Dutt and Sushil Kumar and Yashraj and S. Muralithar and R. P. Singh},
journal= {arXiv preprint arXiv:2211.02406},
year = {2023}
}