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Tutorial of using Multiwfn to perform IRI analysis

Last updated: 2026-Nov-7

Tian Lu (sobereva@sina.com)

Beijing Kein Research Center for Natural Sciences, Beijing 100022, P. R. China (http://www.keinsci.com)

Tutorial Package & PDF Download

All files involved in this tutorial as well as pdf verison of this tutorial can be downloaded at http://sobereva.com/multiwfn/res/IRI_tutorial.zip

Citation Information

If Multiwfn is used in your work to perform the IRI analysis, please cite original papers of Multiwfn, which are shown on screen when Multiwfn boots up; and also cite original paper of the IRI method, which is: Chemistry-Methods, 1, 231-239 (2021) DOI: 10.1002/cmtd.202100007

It is also highly suggested to read my reviews, which involve IRI:

  • Tian Lu and Qinxue Chen, Visualization Analysis of Weak Interactions in Chemical Systems. In Comprehensive Computational Chemistry, vol. 2, pp. 240-264. Oxford: Elsevier (2024) DOI: 10.1016/B978-0-12-821978-2.00076-3

  • Tian Lu, Visualization Analysis of Covalent and Noncovalent Interactions in Real Space, Angew. Chem. Int. Ed., 137, e202504895 (2025) DOI: 10.1002/anie.202504895

Tutorial Contents

  1. Preface
    Brief introduction to IRI, prerequisites, software versions, relationship with RDG/NCI analysis.

  2. Plotting isosurface map of IRI for phenol dimer
    Step-by-step guide to generating high-quality IRI grid data, plotting scatter graph of IRI versus \(\text{sign}(\lambda_2)\rho\), exporting cube files, and rendering color-filled IRI isosurfaces in VMD with IRIfill.vmd.

  3. Plotting color-filled map of IRI on system plane of guanine-cytosine dimer
    Plotting color-filled plane map for GC dimer in Multiwfn, displaying chemical bonds and atom labels, and tuning color scales.

  4. Plotting IRI-π isosurface map for thiophene
    Orbital localization to obtain LMOs, automatic detection and selection of \(\pi\) orbitals, calculating \(\rho\) and \(\text{IRI}\text{-}\pi\) grid data, rendering isosurfaces in VMD with IRIpifill.vmd, and exporting \(\pi\) wavefunction.

  5. Locate minima of IRI-π by basin analysis and topology analysis
    Locating attractors (minima) of \(\text{IRI}\text{-}\pi\) via basin analysis module, visual inspection of attractors, refining accurate positions of minima in topology analysis module, and examining \(\pi\) electron density properties.