Probing transition rates, nuclear moments, and electric dipole polarizability in nobelium using multireference Fock-space relativistic coupled-cluster and perturbed relativistic coupled-cluster theories

We employ an all-particle multireference Fock-space relativistic coupled-cluster theory to compute the ionization potential, excitation energy, transition rate, and hyperfine structure constants associated with the 7s²0.28em0ex¹S₀→7s7p0.28em0ex³P₁ and 7s²0.28em0ex¹S₀→7s7p0.28em0ex¹P₁ transitions in nobelium (No). Using our state-of-the-art calculations in conjunction with available experimental data [S. Raeder et al., Phys. Rev. Lett. 120, 232503 (2018)], we extract the values of nuclear magnetic dipole (μ) and electric quadrupole (Q) moments for ²⁵³No. Further, information on nuclear deformation in even-mass isotopes is extracted from the isotope shift calculations. Moreover, we employ a perturbed relativistic coupled-cluster 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 ≈10% from the perturbative triples to the transition rate of the 7s²0.28em0ex¹S₀→7s7p0.28em0ex³P₁ transition. The largest cumulative contribution from Breit+QED is observed to be ≈4%, to the magnetic dipole hyperfine structure constant of the 7s7p0.28em0ex¹P₁ 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.