A direct measurement of the ground-state-to-ground-state electron-capture decay $Q$ ($Q_{\mathrm{EC}}$) value of ${}^{97}\mathrm{Tc}$ has been conducted employing the high-resolving-power phase-imaging ion-cyclotron-resonance technique with the double Penning trap mass spectrometer JYFLTRAP. The resulting $Q_{\mathrm{EC}}$ value for ${}^{97}\mathrm{Tc}$ is 324.82(21) keV, exhibiting a precision approximately 19 times higher than the value adopted in the newest Atomic Mass Evaluation (AME2020) and differing by $1.2\sigma$. Furthermore, by combining this refined $Q$ value with nuclear energy-level data for the decay-daughter ${}^{97}\mathrm{Mo}$, a potential ultralow $Q$-value transition ${}^{97}\mathrm{Tc}$ ($9/2^{+}$, ground state) $\to {}^{97}\mathrm{Mo}^{*}$ [320(1) keV] was detected. The ground-state-to-excited-state electron-capture decay $Q$ value ($Q_{\mathrm{EC}}^{*}$) of this transition was determined to be 4.8(10) keV, confirming it to be energetically allowed with a confidence level of exceeding $4\sigma$. The captures of electrons occupying the L and higher shells for this transition are energetically allowed, giving a value of 2.0(10) keV for the closest distance of $Q_{\mathrm{EC}}^{*}$ to the allowed binding energy of the L1 shell. To predict partial half-lives and energy-release distributions for this transition, the atomic self-consistent many-electron Dirac-Hartree-Fock-Slater method and the nuclear shell model have been employed. Dominant correction terms such as exchange and overlap corrections, as well as shake-up and shake-off effects, were included in the final results. Moreover, in the case of a possible allowed transition, the normalized distribution of released energy in the electron-capture decay of ${}^{97}\mathrm{Tc}$ to the excited 320-keV state of ${}^{97}\mathrm{Mo}$, is compared with that of ${}^{163}\mathrm{Ho}$, which is being used for electron-neutrino-mass determination. A pseudoexperiment technique was introduced to calculate error propagation in half-life and the 68% confidence interval for normalized energy distributions.

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• Beta decay
• Binding energy & masses
• Electroweak interactions in nuclear physics
• Nuclear decay
• Nuclear structure & decays
• 90 ≤ A ≤ 149
• Nuclear binding