Spin-polarized alkali-metal trimers revisited

Homonuclear spin-polarized alkali-metal trimers in their lowest-lying electronic state are investigated theoretically. Their equilibrium geometries and binding energies are determined with the state-of-the-art quantum chemical methods at three levels of approximation. The equilibrium geometries obtained Req(Li3) = 3.100 Å, Req(Na3) = 4.353 Å, Req(K3) = 4.996 Å, Req(Rb3) = 5.391 Å, and Req(Cs3) = 5.730 Å are compared to the other theoretical results and also to the very recent experimental results obtained through the laser-induced Coulomb explosion. Further theoretical studies are proposed, which could help with better interpretation of the experimental results for the sodium and cesium trimers.