Tootfinder

Probing transition rates, nuclear moments and electric dipole polarizability in nobelium using multireference FSRCC and PRCC theories
Ravi Kumar, Palki Gakkhar, D. Angom, B. K. Mani
https://arxiv.org/abs/2507.20875 https://arxiv.org/pdf/2507.20875 https://arxiv.org/html/2507.20875
arXiv:2507.20875v1 Announce Type: new
Abstract: We employ an all-particle multireference Fock-space relativistic coupled-cluster (FSRCC) theory to compute the ionization potential, excitation energy, transition rate and hyperfine structure constants associated with $7s^2\;^{1}S_{0}\rightarrow 7s7p\;^{3}P_{1}$ and $7s^2\;^{1}S_{0}\rightarrow 7s7p\;^1P_{1}$ transitions in nobelium (No). Using our state-of-the-art calculations in conjunction with available experimental data \cite{raeder-18}, we extract the values of nuclear magnetic dipole ($\mu$) and electric quadrupole ($Q$) moments for $^{253}$No. Further, information on nuclear deformation in even-mass isotopes is extracted from the isotope shift calculations. Moreover, we employ a perturbed relativistic coupled-cluster (PRCC) theory to compute the ground state electric dipole polarizability of No. In addition, to assess the accuracy of our calculations, we compute the ionization potential and dipole polarizability of lighter homolog ytterbium (Yb). To account for strong relativistic and quantum electrodynamical (QED) effects in No, we incorporate the corrections from Breit interaction, vacuum polarization and self-energy in our calculations. The contributions from triple excitations in coupled-cluster is accounted perturbatively. Our calculations reveal a significant contribution of $\approx$10\% from the perturbative triples to the transition rate of $7s^2\;^1S_{0}\rightarrow 7s7p\;^3P_{1}$ transition. The largest cumulative contribution from Breit QED is observed to be $\approx$4\%, to the magnetic dipole hyperfine structure constant of $7s7p\;^1P_{1}$ state. Our study provides a comprehensive understanding of atomic and nuclear properties of nobelium with valuable insights into the electron correlation and relativistic effects in superheavy elements.
toXiv_bot_toot

Isotope shift for total electron binding energy of atoms
V. A. Dzuba, V. V. Flambaum
https://arxiv.org/abs/2507.21410 https://arxiv.org/pdf/2507.21410 https://arxiv.org/html/2507.21410
arXiv:2507.21410v1 Announce Type: new
Abstract: We compute the isotope shifts of the \emph{total} electron binding energy of neutral atoms and singly charged ions up to element $Z=120$, using relativistic Hartree-Fock method including the Breit interaction. Field shift coefficients are extracted by varying the nuclear charge radius; a small quadratic term is retained to cover large radius changes relevant to superheavy nuclei. We tabulate isotope shift coefficients for closed shell systems from Ne to Og and benchmark selected open shell cases, used to test the interpolation formula. A simple power law interpolation $bZ^k$ reproduces calculated field shifts to within about 1\% across the table, with the effective exponent $k$ growing from roughly 5 near $Z \sim 50$ to about 12 at $Z \sim 118$. Due to the domination of inner shells, differences between neutrals and singly charged ions does not exceed few percent, becoming noticeable mainly when an outer $s$ electron is removed. Therefore, these results may also be used for higher charge ions.
toXiv_bot_toot