Finite temperature behavior of impurity doped Lithium cluster,Li_6Sn

摘要

We have carried out extensive isokinetic ab initio molecular-dynamic simulations to investigate the finite temperature properties of the impurity doped cluster Li_6Sn and the host cluster Li_7.The data obtained from about 20 temperatures and total simulation time of at least 3 ns is used to extract thermodynamical quantities like canonical specific heat.We observe that,first,Li_6Sn becomes liquidlike around 250 K,at much lower temperature than that for Li_7(approx=425 K).Second,a weak shoulder around 50 K in the specific heat curve of Li_6Sn is observed due to the weakening of Li-Li bonds.The peak in te specific heat of Li_7 is very broad and the specific heat curve does not show any premelting features.