Automated Assembly of Secondary Building Units AASBU Method

3 Automated Assembly of Secondary Building Units (AASBU Method) 

Generally, SBUs can be used to describe the structures of microporous inorganic crystals. Draznieks et al. developed a computational method for the prediction of inorganic crystal structures through automated assembly of secondary building units (AASBU).[35,36] This 

During the simulations, the SBUs are treated as rigid bodies. The rule that controls the possible assembly of D4R units is a force field with some Lennard-Jones expressions that essentially favor the attraction between ligand atoms. In other words, this force field favors the formation of L - L sticky-atom pairs and allows two D4R units to assemble 

There exist several linkages of the SBUs which should be avoided, for example, the short separation of two metal atoms (M Mj), one ligand atom and one bridging atom (Lj Bj), and L Mj in SBUs unlinked. To prevent these undesirable linkages, other potential functions have to be considered, including the repulsive potential between Mj Mj pairs, the attractive potential between L, - - - Mj pairs, and the repulsive potential between Lj Bj pairs. A repulsive potential between Mr Mj pairs prevents SBUs from overlapping with each other. The distance between the Mr Mj pair is limited to 3.4 A for D4R. The Lennard-Jones potential parameters used in assembling the D4R are provided in Table 7.2. 

The total energy (Etotai) of all the D4Rs in one unit cell can be defined as  

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C.M. Draznieks, De novo Prediction of Inorganic Structures developed through Automated Assembly of Secondary Building Units (AASBU method). Angew. Chem., Int. Ed., 2000, 39,... 

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