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)/e2a02Eh-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).