Simulated annealing construction of molecular graphs with required properties

The method of simulated annealing for the construction of molecular graphs with required properties was studied. The method depends on the already available functional relationship that transforms molecular structural features into a numerical value of a property. The simulated annealing was initialized by a randomly generated molecular graph. A molecular graph was perturbed onto another molecular graph so that starting from a randomly selected point the rest of the numerical code of the current graph was replaced by a randomly generated code. The acceptance of the generated code to the next process of simulated annealing was solved by the Metropolis criterion. After the prescribed number of steps the temperature was multiplicatively decreased. Two types of molecular graphs were studied. The first type of molecular graphs was acyclic graphs (trees) that are simply represented by a numerical code composed of the same number of entries as the number of vertices in molecular graphs. perturbation operations consist of simple changes of numerical codes. The second type of molecular graphs was cyclic connected graphs (q > p - 1, where p and q are numbers of vertices and edges, respectively) that are represented by the lower-triangle part of adjacency matrices. The efficiency of the proposed method is illustrated by model calculations, wherein molecular graphs with required properties are constructed.