Density functional studies of Li-N and Li-N(+) (N = 2-30) clusters: Structure, binding and charge distribution

作者：Goel Neetu^*; Gautam Seema; Dharamvir Keya

来源：International Journal of Quantum Chemistry, 2012, 112(2): 575-586.

DOI：10.1002/qua.23022

• DFT
• clusters
• charge distribution
• binding energy
• stability
• symmetry

Density functional calculations using B3LYP/6-311G method have been carried out for small to medium-sized lithium clusters (LiN, N = 230). The optimized geometries of neutral and singly charged clusters, their binding energies, ionization potential, electron affinity, chemical potential, softness, hardness, highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO-LUMO) gap, and static dipole polarizability have been investigated systematically. In addition, we study the distribution of partial charges in detail using natural population analysis (NPA) in small-sized clusters (LiN, N = 210), both neutral and cationic, and demonstrate the correlation between symmetry and charge. Uniform distribution of charges in cationic clusters confirms them to be energetically more favorable than the neutral counterparts. Whenever possible, results have been compared with available data. An excellent agreement in every case supports new results as reliable predictions. A careful study of optimized geometries shows that Li-9 is derivable from bulk Li structure, i.e., body centered cubic cell, and higher clusters have optimized shapes derived from this. Further, the turnover form two to three dimensional structure occurs at cluster size N = 6. The quantity alpha(1/3) (alpha = polarizability) per atom is found to be broadly proportional to softness (per atom) as well as inverse ionization potential (per atom). The present work forms a sound basis for further study of large-sized clusters as well as other atomic clusters.

• 出版日期2012-1-15