Formation Mechanism and Binding Energy forRegular Tetrahedral Structure of Li4

Abstract

The formation mechanism for the regular tetrahedralstructure of Li4 cluster is proposed. The curve of the totalenergy versus the separation R between the two nuclei has beencalculated by using the method of Gou's modified arrangementchannel quantum mechanics (MACQM). The result shows that thecurve has a minimal energy of -29.8279 a.u. at R = 14.50 a0. WhenR approaches infinity the total energy of four lithium atomshas the value of -29.7121 a.u. So the binding energy of Li4 withrespect to four lithium atoms is the difference of 0.1158 a.u.forthe above two energy values. Therefore the binding energy peratom for Li4 is 0.029 a.u., or 0.7878 eV, which is greater thanthe binding energy per atom of 0.453 eV for Li2, the binding energyper atom of 0.494 eV for Li3 and the binding energy per atom of0.632 eV for Li5 calculated previously by us. This means thatthe Li4 cluster may be formed stably in a regular tetrahedralstructure of side length R = 14.50 a0 with a greater bindingenergy.