High-accuracy relativistic many-body calculations of van der Waals coefficients $C_6$ for alkaline-earth-metal atoms

Relativistic many-body calculations of van der Waals coefficients $C_6$ for dimers correlating to two ground-state alkaline-earth-metal atoms at large internuclear separations are reported. The following values and uncertainties were determined: $C_6=214\mathrm{}\left(3\right)\mathrm{}$ for Be, 627(12) for Mg, 2221(15) for Ca, 3170(196) for Sr, and 5160(74) for Ba in atomic units.