Investigation of Topology-distinct Stable Structures for Hydrogen Fluoride Clusters (HF)n (n=2-8) by the Methods of Graph Theoretical Enumerations and Quantum Chemical Calculations

A graph theoretical procedure to generate all the possible topology. distinct structures for hydrogen fluoride(HF) clusters was presented and all the possible topology. distinct structures for hydrogen fluoride (HF)(n) (n = 2-8) clusters were enumerated in this work. On the basis of the restrictions found, FORTRAN program was designed and executed by Python program, and the corresponding diagraphs or restrictive digraphs were drawn by means of free graph visualization software, GraphViz 2. 38 for HF cluster (HF)(n) (n = 2-8). Within the theoretical framework of the corresponding digraphs or restrictive digraphs, all the topology. distinct local minima for (HF)(n) (n = 3-7) were optimized and analyzed by means of ab initio method and density functional theory (DFT) method at the level of MP2/6-31G** (d, p) and B3LYP/6-31G**(d, p), respectively. The local minimum structures for (HF)(n) (n = 3-7) are the same as those in the previous works. For HF pentamer, hexamer and heptamer, some new local minimum structures were obtained.