Relativistic calculations of $C_6$ and $C_8$ coefficients for strontium dimers

TL;DR

This paper presents high-precision relativistic calculations of dispersion coefficients for strontium dimers, providing key data for understanding long-range interactions and confirming experimental results.

Contribution

The study introduces a combined relativistic configuration interaction and coupled-cluster approach to accurately compute $C_6$ and $C_8$ coefficients for strontium dimers, with results validated against experimental data.

Findings

Calculated $C_6$ coefficients agree with experimental photoassociation data.

Provided $C_8$ coefficients essential for modeling long-range potentials.

Confirmed the experimental magic wavelength for the $^1S_0$-$^3P_1^o$ transition.

Abstract

The electric dipole and quadrupole polarizabilities of the $5s5p~^3\!P_1^o$ state and the $C_6$ and $C_8$ coefficients for the $^1\!S_0 +\, ^1\!S_0$ and $^1\!S_0 +\, ^3\!P_1^o$ dimers of strontium are calculated using a high-precision relativistic approach that combines configuration interaction and linearized coupled-cluster methods. Our recommended values of the long range dispersion coefficients for the $0_u$ and $1_u$ energy levels are $C_6(0_u)=3771(32)$ a.u. and $C_6(1_u)= 4001(33)$ a.u., respectively. They are in good agreement with recent results from experimental photoassociation data. We also calculate $C_8$ coefficients for Sr dimers, which are needed for precise determination of long-range interaction potential. We confirm the experimental value for the magic wavelength, where the Stark shift on the $^1\!S_0$-$^3\!P_1^o$ transition vanishes. The accuracy of calculations is analyzed and uncertainties are assigned to all quantities reported in this work.