The polarizability of sodium: theory and experiment reconciled

Coupled cluster computations using large basis sets and the Douglas–Kroll Hamiltonian for relativistic effects are reported for the dipole polarizability, α, of the sodium atom. Our best value of α ( Na ) / e 2 a 0 2 E h - 1 = 162.88 ± 0.6 is in excellent agreement with the value obtained by atomic-beam interferometry, thus resolving a persistent discrepancy between theory and experiment. Combining our α(Na) with a very accurate value of α(Li), we find that α(Li)/α(Na) = 1.0071 ± 0.0037 establishing that α(Li) is greater than α(Na).