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We have performed a theoretical study concerning the analysis of the nuclear and atomic resonance conditions for 110mAg isomer depletion through nuclear excitation by electron capture (NEEC). This analysis includes selection of the relevant fusion-evaporation reaction for 110mAg isomer production and calculation of its cross section. Moreover, using the relativistic multiconfiguration Dirac-Fock method, calculations of the dependence of the energy released by electron capture into specific atomic subshells (N, O and P) on the 110mAg ion charge state have been carried out. In addition, the potentially possible kinetic energy of the NEEC resonance and predictions of the mean equilibrium charge state for the 110mAg recoil ions as a function of its kinetic energy in the C stopping medium have been evaluated. [ABSTRACT FROM AUTHOR]

We present theoretical research on the optimal atomic resonance conditions for long-lived (T1=2 ~ 6.85 h) 93mMo isomer depletion via nuclear excitation by electron capture (NEEC) in a beam-based scenario. Analysis of potentially possible NEEC-resonance kinetic energy and predictions of the mean equilibrium charge state for the 93mMo recoil ion as a function of its kinetic energy in the He, C, Mg, and Al stopping media have been performed. We have found for the solid targets the high probability of observing the NEEC process for electron capture into M subshells for q = +33 charge state, and also significant probability for electron capture into N subshells for q = +34. Moreover, we have concluded that, for the studied solid targets, the occurrence of NEEC seems to be more probable than for a He gas target. The results of our study should be an important step toward the controlled release of energy stored in the nuclear isomer of some elements and may also be useful in the development of a new class of nuclear energy sources. [ABSTRACT FROM AUTHOR]

For a better understanding of the nature of isomer depletion via the nuclear excitation by electron capture (NEEC) process, we have presented here, for the long-lived (T1/2 ~ 6.85 h) 93mMo isomer, the results of highprecision multiconfiguration Dirac-Fock calculations concerning the dependence of the energy released by electron capture into different atomic subshells of the N, M, and L shells on the specific charge state. These energy values can be understood as benchmarks, i.e., reference parameters, which are crucial for implementations of the proposed beam-based scenario approach for different stopping targets. The authors believe that this detailed analysis of the atomic conditions for the NEEC process should be a first step to applied research, which aims to allow the controlled release of energy stored in the nuclear isomer of selected elements. The presented studies may contribute to the development of the concept of new, unconventional, and ultra-energy-dense nuclear power sources. [ABSTRACT FROM AUTHOR]

A novel approach for isomer depletion in ion-atom collisions is proposed and considered theoretically. Analyses are performed for the depletion of the 93mMo isomer for which an unexpectedly large probability was measured in the beam-based experiment of Chiara et al. [Nature (London) 554, 216 (2018)]. The subsequent attempt at a theoretical description based on state-of-the-art atomic theory did not reproduce the experimental result [Wu et al., Phys. Rev. Lett. 122, 212501 (2019)] and showed a dramatic disagreement with the experiment (by many orders of magnitude). This conflict calls for further research on the nature of isomer depletion mechanisms occurring in atomic processes. Here, we propose to consider the 93mMo isomer depletion as the nuclear excitation by electron capture in resonant transfer process taking into account the momentum distribution of the target electrons. Although our results only slightly shift the upper theoretical limit for the total 93mMo isomer depletion probability toward the experimental value, they show the importance of considering the Compton profile in the theoretical description, in particular for the L shell, for which the depletion probability increases by many orders of magnitude. [ABSTRACT FROM AUTHOR]

Following the first experimental observation of 93mMo isomer depletion via nuclear excitation by electron capture (NEEC), we consider another experimental scenario related to the 242mAm isomer for which the probability of the NEEC process is expected to be even higher than for the 93mMo isomer. The optimum experimental conditions for the production and depletion of the 242mAm isomer in a beam-based scenario are discussed. The relevant beam-target reaction cross sections have been calculated striving to ensure effective production of the 242mAm isomer. Kinetic energies required for the NEEC process to occur have been predicted for the n=5, 6, and 7 subshells of 242mAm ions and combined with available ion charge states at subsequent stages of the ion stopping process. The NEEC resonance strengths have been estimated for the partial contributions of individual subshells to the whole NEEC process. [ABSTRACT FROM AUTHOR]