Non-relativistic ab initio calculations for $2^2S$, $2^2P$ and $3^2D$ lithium isotopes: Applications to polarizabilities and dispersion interactions

TL;DR

This paper presents non-relativistic ab initio calculations of polarizabilities and dispersion coefficients for lithium isotopes in various states, highlighting isotope effects and discrepancies with experimental data.

Contribution

It provides new high-precision calculations of polarizabilities and dispersion coefficients for lithium isotopes, including analysis of isotope sensitivity and comparison with existing results.

Findings

Second hyperpolarizability of 2^2S state is isotope-sensitive.

Calculated 3^2D state polarizability components disagree with experimental data.

Results enhance understanding of long-range interactions in lithium isotopes.

Abstract

The electric dipole polarizabilities and hyperpolarizabilities for the lithium isotopes $^6$Li and $^7$Li in the ground state $2^2S$ and the excited states $2^2P$ and $3^2D$, as well as the leading resonance and dispersion long-range coefficients for the Li($2^2S$)--Li($2^2S$) and Li($2^2S$)--Li($2^2P$) systems, are calculated nonrelativistically using variational wave functions in Hylleraas basis sets. Comparisons are made with published results, where available. We find that the value of the second hyperpolarizability of the $2^2S$ state is sensitive to the isotopic mass due to a near cancellation between two terms. For the $3^2D$ state polarizability tensor the calculated components disagree with those measured in the sole experiment and with those calculated semi-empirically.