Search for Global Minimum Structures of (n = 1-15) Using xTB-Based Basin-Hopping Algorithm.

Min Zhou,Yicheng Xu,Yongliang Cui,Xianglei Kong,Xianyi Zhang

doi:10.3389/fchem.2021.694156

Abstract

A new program for searching global minimum structures of atomic clusters using basin-hopping algorithm based on the xTB method was developed here. The program can be performed with a much higher speed than its replacement directly based on DFT methods. Considering the structural varieties and complexities in finding their global minimum structures, phosphorus cluster cations were studied by the program. The global minimum structures of cationic (n = 1–15) clusters are determined through the unbiased structure searching method. In the last step, further DFT optimization was performed for the selected isomers. For (n = 1–4, 7), the found global minimum structures are in consistent with the ones previously reported; while for (n = 5, 6, 8–12), newly found isomers are more energy-favorable than those previously reported. And those for (n = 13–15) are reported here for the first time. Among them, the most stable isomers of (n = 4–6, 9) are characterized by their C3v, Cs, C2v and Cs symmetry, in turn. But those of (n = 7, 8, 10–12), no symmetry has been identified. The most stable isomers of and are characterized by single P-P bonds bridging units inside the clusters. Further analysis shows that the pnicogen bonds play an important role in the stabilization of these clusters. These results show that the new developed program is effective and robust in searching global minimum structures for atom clusters, and it also provides new insights into the role of pnicogen bonds in phosphorus clusters.

Highlights

The structural determination of small molecules based on density functional theory (DFT) or other methods has become a relatively routine task for computational chemists, the identification of the global minimum structures for clusters, especially those with large sizes, is still a great challenge
The NKCS program has been tested with the odd-numbered phosphorus cluster cations here
Clusters cationic clusters of P+3, P+5 and P+7, the most stable isomers with D3h, C4v and C2v symmetries in turn, have been revealed by Guo et al (2004), Xue et al (2010) previously

Summary

INTRODUCTION

Molecules and bulk matter (Johnstom, 2002; Castleman and Jena, 2006; Fehlner et al, 2007; Ha et al, 2019), showing their great potentials for applications in many research fields such as catalysis (Liu and Corma, 2018; Du et al, 2020) and energy storage (VanGelder et al, 2018; VanGelder et al, 2019) They are characterized by their geometries and electronic structures in many cases (Johnstom, 2002; Fehlner et al, 2007; Ferrando, 2015; Luo et al, 2016; Jena and Sun, 2018; Ha et al, 2019). The structural determination of small molecules based on density functional theory (DFT) or other methods has become a relatively routine task for computational chemists, the identification of the global minimum structures for clusters, especially those with large sizes, is still a great challenge. Searching for the global minima in their PES is still a challenging task due to the diverse bonding patterns of the element

METHODS

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT