Benchmarking Many-body Approaches for the Determination of Isotope Shift Constants: Application to the Li, Be${}^{+}$ and Ar${}^{15+}$ Isoelectronic Systems

Abstract

We have applied relativistic coupled-cluster (RCC) theory to determine the isotope shift (IS) constants of the first eight low-lying states of the Li, Be${}^{+}$ and Ar${}^{15+}$ isoelectronic systems. Though the RCC theory with singles, doubles and triples approximation (RCCSDT method) is an exact method for these systems for a given set of basis functions, we notice large differences in the results from this method when various procedures in the RCC theory framework are adopted to estimate the IS constants. This has been demonstrated by presenting the IS constants of the aforementioned states from the finite-field, expectation value and analytical response (AR) approaches of the RCCSDT method. Contributions from valence triple excitations, Breit interaction and lower-order QED effects to the evaluation of these IS constants are also highlighted. Our results are compared with high-precision calculations reported using few-body methods wherever possible. We find that results from the AR procedure are more reliable than the other two approaches. This analysis is crucial for understanding the roles of electron correlation effects in the accurate determination of IS constants in the heavier atomic systems, where few-body methods cannot be applied.

16 pages, 13 tables

References in corpus (8)

• An improved calculation of the isospin-symmetry-breaking corrections to superallowed Fermi beta decay
• Relativistic, QED, and finite nuclear mass corrections for low-lying states of Li and Be${}^{+}$
• Relativistic recoil, electron-correlation, and QED effects on the 2p_j-2s transition energies in Li-like ions
• Isotope Shifts in Beryllium-, Boron-, Carbon-, and Nitrogen-like Ions from Relativistic Configuration Interaction Calculations
• Relativistic corrections to isotope shift in light ions
• Relativistic calculations of the isotope shifts in highly charged Li-like ions
• Analytic Response Relativistic Coupled-Cluster Theory: The first application to indium isotope shifts
• Non-linear isotope-shift effects in Be-like, B-like, and C-like argon

Cited by in corpus (4)

• Isotope Shifts in Cadmium as a Sensitive Probe for Physics Beyond the Standard Model
• Nuclear charge radii of Na isotopes: A tale of two theories
• All-optical Differential Radii in Zinc
• Isotope-shift factors with quantum electrodynamics effects for many-electron systems: A study of the nuclear charge radius of ${}^{26m}$Al