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 $R_{\rm eq}({\rm Li}_3) = 3.100$ \r{A}, $R_{\rm eq}({\rm Na}_3) = 4.353$ \r{A}, $R_{\rm eq}({\rm K}_3) = 4.996$ \r{A}, $R_{\rm eq}({\rm Rb}_3) = 5.391$ \r{A}, and $R_{\rm eq}({\rm Cs}_3) = 5.730$ \r{A} are compared to the other theoretical results and also with 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.