Accurate relativistic many-body calculations of van der Waals coefficients C_8 and C_10 for alkali-metal dimers

Sergey Porsev; Andrei Derevianko

doi:10.1063/1.1578052

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Accurate relativistic many-body calculations of van der Waals coefficients C_8 and C_10 for alkali-metal dimers

Sergey Porsev·Andrei Derevianko

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Abstract

We consider long-range interactions between two alkali-metal atoms in their respective ground states. We extend the previous relativistic many-body calculations of C_6 dispersion coefficients [Phys.Rev. Lett. {\bf 82}, 3589 (1999)] to higher-multipole coefficients C_8 and C_10. A special attention is paid to usually omitted contribution of core-excited states. We calculate this contribution within relativistic random-phase approximation and demonstrate that for heavy atoms core excitations contribute as much as 10% to the dispersion coefficients. We tabulate results for both homonuclear and heteronuclear dimers and estimate theoretical uncertainties. The estimated uncertainties for C_8 coefficients range from 0.5% for Li_2 to 4% for Cs_2.

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Sergey Porsev, Andrei Derevianko. 2003-03-12. Accurate relativistic many-body calculations of van der Waals coefficients C_8 and C_10 for alkali-metal dimers. https://doi.org/10.1063/1.1578052

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