The ISOTILT software for discovering cooperative rigid‐unit rotations in networks of interconnected rigid units

• Published in: Journal of applied crystallography Vol. 54; no. 6; pp. 1847 - 1856
• Main Authors: Campbell, Branton J., Stokes, Harold T., Averett, Tyler B., Machlus, Shae, Yost, Christopher J.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01-12-2021; Blackwell Publishing Ltd
• Subjects: Algorithms; Computer Programs; group representation theory; ISOTILT; Isotropy; Mathematical analysis; rigid‐unit modes; Singular value decomposition; Software; Software development tools; Software packages; Symmetry; symmetry modes; group representation theory; symmetry modes; ISOTILT; rigid-unit modes; singular value decomposition
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S1600576721009353

A user‐friendly web‐based software tool called `ISOTILT' is introduced for detecting cooperative rigid‐unit modes (RUMs) in networks of interconnected rigid units (e.g. molecules, clusters or polyhedral units). This tool implements a recently described algorithm in which symmetry‐mode patterns of pivot‐atom rotation and displacement vectors are used to construct a linear system of equations whose null space consists entirely of RUMs. The symmetry modes are first separated into independent symmetry‐mode blocks and the set of equations for each block is solved separately by singular value decomposition. ISOTILT is the newest member of the ISOTROPY Software Suite. Here, it is shown how to prepare structural and symmetry‐mode information for use in ISOTILT, how to use each of ISOTILT's input fields and options, and how to use and interpret ISOTILT output.
ISOTILT is a user‐friendly web‐based software package for discovering the cooperative rigid‐unit modes in materials whose structures contain interconnected networks of rigid units.