Magic wavelength of the Ba-138(+) 6s S-2(1/2)-5d D-2(5/2) clock transition

The zero crossing of the dynamic differential scalar polarizability of the S-1/2 - D-5/2 clock transition in Ba-138(+) has been determined to be 459.1614(28) THz. Together with previously determined matrix elements and branching ratios, this tightly constrains the dynamic differential scalar polarizability of the clock transition over a large wavelength range (greater than or similar to 700 nm). In particular, it allows an estimate of the blackbody radiation shift of the clock transition at room temperature.