ESCHER - A computer program for the determination of external rotational symmetry numbers from molecular topology

W. P. Walters, Samuel H Yalkowsky

Research output: Contribution to journalArticle

20 Scopus citations


An algorithm for determining the external rotational symmetry number of a molecule from a SMILES1 string has been developed. ESCHER operates by first locating the center or centers of graphical symmetry for the molecule and the equivalence classes of atoms connected to the center or centers. The center(s) of graphical symmetry is the atom(s) which is(are) most symmetrical with respect to the connections to other atoms. These are then used to calculate the symmetry number, σ.

Original languageEnglish (US)
Pages (from-to)1015-1017
Number of pages3
JournalJournal of Chemical Information and Computer Sciences
Issue number5
Publication statusPublished - Sep 1996


ASJC Scopus subject areas

  • Chemistry(all)
  • Computational Theory and Mathematics
  • Computer Science Applications
  • Information Systems

Cite this