The 114In level scheme studied by the (n, γ) reaction

Abstract

The level scheme of the nucleus 114In has been studied using capture of thermal neutrons. The experimental information is taken from γ singles spectra and γ- γ coincidence spectra and from delayed coincidence measurements. Levels up to 1.4 MeV excitation energy are proposed. Several short lifetimes of excited states in 114In and 116In could be measured. The binding energy of the last neutron in 114In, B n = 7273.9 ± 1.2 keV, determined in this work is in strong disagreement with previously accepted values. Additional experimental information on the 116In level scheme is given. Six states of the ( π( g 9 2 ) −1, ν h 11 2 ) multiplet (3 − to 8 −) in 114In. The expected close similarity between many low-lying states in 114In and 116In could be confirmed. In particular, it was found that the anomalous high isomeric cross-section ratio of the second isomeric state results from very selective reorientation transitions within the negative-parity multiplet. The coupling constant of the quadrupole part of the residual neutron-proton interaction obtained from a theoretical calculation of the 114In level scheme is similar in size to that of 116In, thus giving credit to the explanation given in our previous 116In work. The splitting of multiplets in doubly odd In nuclei gives additional information for an interpretation of the so-called g 7 2 − h 11 2 anomaly in stripping studies near A = 110. Transition probability ratios B(M1)/ B(E2) and E1 hindrance factors are discussed for both 114In and 116In. No sign of states exhibiting stable deformation similar to those in odd- A In nuclei has been found up to now in the doubly odd In nuclei studied. There is some evidence that these doubly odd In nuclei behave more like Cd than like single closed shell Sn nuclei.