Interactive simulation of molecule vibration and rotation modes  
[ Français ]  
Marc Couture
Télé-université, Université du Québec à Montréal (Canada)
with the collaboration of Alexandre Ayotte, Cyberlude Inc.

VR Molecules Pro is a simulation illustrating dynamically and interactively the vibration and rotation modes for 24 molecules (out of a more extensive list) containing up to twelve atoms. Much in the same way as a Power Point presentations, one can create documents containing up to 10 "pages", each featuring one or two molecules with specific parameters (viewpoint, active modes, viewing options, etc.). These documents can be saved on one's computer, or uploaded on a online server, for later reloading or reuse.

One can also associate sound and text explanations to each page of an online presentation, thus creating a full-fledged multimedia document. Note that software to edit simple HTML documents and to create MP3 sound files is required.

Two versions of VR Molecules are available:

  1. A stand-alone application, available for both Windows and Macintosh, as a set of files included:

    Note. The application runs on all Windows versions from XP to Win 10, but I haven't tested it on recent versions of Mac OS.

  2. An online version (opens in a new window) running in Firefox (32-bit version) under Windows. If the online application doesn't start (in the new window), see the following explanations for guidance.

Download and "installation" instructions stand-alone version (Windows)

  1. Click on this link VR_Molecules_Pro_en.zip with the right mouse button and select Save target (or link) as.... Note the location (folder) where the file is downloaded, or choose an easy-to-retrieve location on your computer.

  2. In the folder where the file VR_Molecules_Pro_en.zip has been downloaded, click on its icon, again with the right mouse button, and select Extract All. This will create a folder named VR_Molecules_Pro_en.

  3. This folder contains a sub-folder named dswmedia, a help file userGuide.htm, and the application itself, named VR Molecules Pro.exe (the .exe extension may not be visible). Double-click this file to launch VR Molecules Pro.

Please note that this executable file is not an installer but the ready-to-run application. This means that no change is made to your system, thus there is no risk of conflict between VR Molecules Pro and other programs installed on your computer.

For the same reason, to eliminate VR Molecules Pro from your computer, you simply need to delete the VR_Molecules_Pro_en folder with all its content.

For explanations on VR Molecules Pro features, click in its title bar on the icon to activate / deactivate tool tips or on the icon to access the user guide.

For further information, or if you are interested in collaborating to the enhancement of VR Molecules (v.g. adding new molecules, improving the existing functionalities), or to research/discussion about its use as a teaching/learning tool, please contact the author, Marc Couture. You can also find other simulation and(or) multimedia software for science education on the author's website.


In the simulation, all vibration frequencies and atom equilibrium positions are "exact" (v.g. not calculated by a molecular modeling software but obtained from handbooks or public databases),while displacements of atoms in the various vibration modes are calculated using the simple (classical) models used in most of the literature. However, for spatial (i.e. non-planar) molecules, some mode configurations were deduced from figures in Herzberg's book [1]; in these cases, the resulting inaccuracy has been limited by requiring momentum and angular momentum conservation.

1. Herzberg, Gerhard (1967). Molecular Spectra and Molecular Structure - Infrared and Raman Spectra of Polyatomic Molecules (2nd ed.). Toronto: Van Nostrand Reinhold.

Last updated: October 25, 2016

Licence Creative Commons Canada 2.5

VR Molecules Pro is licensed under the
Creative Commons Attribution - Noncommercial 2.5 Canada license.