Symmetry and Enumeration of Molecules

The geometrical symmetries of a molecule M are reflected in its molecular properties and so studying different types of symmetry groups for M are important in Chemical Group Theory. The topological symmetry group refers to the maximum possible symmetry achievable by a molecular structure and can be computed by permutations within the adjacency matrix of M. To enumerate the different types of isomers for M, we have to first compute its symmetry group. In this lecture, all types of symmetry groups together with techniques for computing isomers will be presented. We also discuss some very important ideas developed essentially by Shinsako Fugita. Keywords: Point group, topological symmetry group, Polya enumeration technique.