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 $R_{\mathrm{e}\mathrm{q}}({\mathrm{L}\mathrm{i}}_3)=3.100$ Å, $R_{\mathrm{e}\mathrm{q}}({\mathrm{N}\mathrm{a}}_3)=4.353$ Å, $R_{\mathrm{e}\mathrm{q}}({\mathrm{K}}_3)=4.996$ Å, $R_{\mathrm{e}\mathrm{q}}({\mathrm{R}\mathrm{b}}_3)=5.391$ Å, and $R_{\mathrm{e}\mathrm{q}}({\mathrm{C}\mathrm{s}}_3)=5.730$ Å 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.