Lowest-energy structures and electronic properties of Na-Si binary clusters from ab initio global search

Abstract

The ground state structures of neutral and anionic clusters of Na(n)Si(m) (1 ≤ n ≤ 3, 1 ≤ m ≤ 11) have been determined using genetic algorithm incorporated in first principles total energy code. The size dependence of the structural and electronic properties is discussed in detail. It is found that the lowest-energy structures of Na(n)Si(m) clusters resemble those of the pure Si clusters. Interestingly, Na atoms in neutral Na(n)Si(m) clusters are usually well separated by the Si(m) skeleton, whereas Na atoms can form Na-Na bonds in some anionic clusters. The ionization potentials, adiabatic electron affinities, and photoelectron spectra are also calculated and the results compare well with the experimental data.

Global optimization of clusters using electronic structure methods

“…The located putative GM (isomer found in generation 13) agrees with predictions from Ref. [127]. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]…”

“…In contrast, for the GA-DFT run shown in Figure 6, only about 370 DFT calculations were necessary until the algorithm converged to the same structure proposed in Ref. [127] as the putative GM. For FP-GOs in particular, this is a double-edged problem.…”

“…Genetic algorithm Main-group elements and coinage metals Li, [117] Cs, [119] B, [118] Al, [138] Ga, [139] Si, [140] Sn, [130,[134][135][136] Pb, [141] P, [142] As, [142] Bi, [143] Cu, [126,144] Ag, [94,125,126] Au [94,125,126,145] Nanoalloys Na-Si, [127] Sn-Bi, [146,147] Ag-Cu, [126] Au-Cu, [126] Au-Ag [94,125] Oxide a and other systems Li-O, [148] Be-O, [149] Mg-O, [150,151] B-O, [152] Al-O, [153] Ce-O, [154] W-O, [155] Li-F, [156] Al-H, [157] B-C, [158] Li-Al-B, [159] H 2 O-H [160] Complex systems Ag-Lig, [161] Au-Surf, [131,162] Au-Pd-Surf [162] Basin hopping Homoatomic B, <...>…”

“…6) agrees with the previous work of Kumar and coworkers. [127] They investigated the neutral and anionic Na-Si system (with a maximum of three Na and 11 Si atoms), using with a population-based GA-DFT and applying energy and moment of inertia criteria in the natural selection step. However, in their investigation 1000-3000 genetic operations were applied and, consequently, the same number of DFT optimizations have been performed for every cluster size.…”

Comprehensive genetic algorithm forab initioglobal optimisation of clusters

“…Independently, different groups in the world have developed their own GA codes for ab initio optimisation of clusters. [23,26,[38][39][40][41][42][43] A large variety of elemental clusters have been explored, such as K n (n ≤ 20), [44] Cs n (n ≤ 20), [45] Al n + and Al n − (n ≤ 34), [46] 9-n Bi n (n = 0-4), [56] Sn m-n Bi n (m = 5-13, n = 1-2), [57] as well as metal oxide clusters such as (LiO) [1][2][3][4][5][6][7][8] [78] have been determined and their electronic properties have been investigated and compared with experiments. In the following, we will describe the technique details of CGA for cluster optimisation and give some examples for the practical applications of CGA for different kinds of elemental clusters, alloy clusters and metal oxide clusters.…”