Wiener index

In chemical graph theory, the Wiener index (also Wiener number) is a topological index of a molecule, defined is the sum of the numbers of edges in shortest paths in a chemical graph between all pairs of non-hydrogen atoms in a molecule. It was introduced by H. Wiener in 1947. Wiener index may be calculated using the Floyd algorithm. Bojan Mohar and Tomaž Pisanski presented an efficient algorithm for computing the Wiener index of a tree.

Wiener index is the oldest topological index related to molecular branching. A tentative explanation of the relevance of the Wiener index in reseacrh of QSPR and QSAR is that it correlates with the van der Waals surface area of the molecule. Also, different modifications of Wiener index were introduced (for example, Extended Wiener index ).