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arXiv · 1910.07934

A Comparative Analysis of Non-relativistic and Relativistic Calculations of Electric Dipole Moments and Polarizabilities of Heteronuclear Alkali Dimers

R. Mitra·V. S. Prasannaa·B. K. Sahoo
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Abstract

We analyze the molecular electric dipole moments (PDMs) and static electric dipole polarizabilities of heteronuclear alkali dimers in their ground states by employing coupled-cluster theory, both in the non-relativistic and four-component relativistic frameworks. The roles of electron correlations as well as relativistic effects are demonstrated by studying them at different levels of theory, followed by a comprehensive treatment of error estimates. We compare our obtained values with the previous non-relativistic calculations, some of which include lower-order relativistic corrections, as well as with the experimental values, wherever available. We find that the PDMs are very sensitive to relativistic effects, as compared to polarizabilities; this aspect can explain the long-standing question on the difference between experimental values and theoretical results for LiNa. We show that consideration of relativistic values of PDMs improves significantly the isotropic Van der Waals $C_6$ coefficients of the investigated alkali dimers over the previously reported non-relativistic calculations. The dependence of dipole polarizabilities on molecular volume is also illustrated.

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R. Mitra, V. S. Prasannaa, B. K. Sahoo. 2019-10-17. A Comparative Analysis of Non-relativistic and Relativistic Calculations of Electric Dipole Moments and Polarizabilities of Heteronuclear Alkali Dimers. https://doi.org/10.1103/physreva.101.012511

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