VR Molecules is an online simulation which uses the Adobe Shockwave browser plugin to dynamically and interactively present the vibration and rotation modes for 24 molecules (out of a more extensive list) containing up to twelve atoms. It allows the user to create a document containing, much in the same way as a Power Point presentation, up to 10 "pages", each featuring one or two molecules with specific parameters (viewpoint, active modes, etc.). The user operates sliders to set the quantum numbers and then observes a simulation of the molecule vibrating in response to these settings. The plug-in can simulate two molecules at the same time so that comparisons the between the same or different molecules can be made.
The major learning goals of this site are to give the student a detailed understanding of the coupling of vibrational and rotational modes of a molecule.
Target Student Population:
The plug-in is targeted to students enrolled in upper level undergraduate chemistry and physics courses. The plug-in could also be used to introduce the concepts of molecular vibrations to students enrolled in introductory undergraduate courses.
Prerequisite Knowledge or Skills:
Users of this site need to be familiar with the concepts of quantized vibrational and rotational motion and zero point energy.
Type of Material:
The site contains an interactive animation/simulation of simple molecules in which the user can alter the quantum number of the rotational and/or vibrational modes, as well as displaying several molecules on the screen at the same time.
The plug-in should be most useful for students studying quantum mechanics and vibrational spectroscopy as it can be used to illustrate quantized vibrational and rotational motion for small molecules in any theoretical discussion of the rigid rotor, normal modes etc.
A web browser with the Macromedia Shockwave browser plug-in installed.
Evaluation and Observation
1. The ability to alter the quantum number of the rotational and vibrational modes is a magnificent feature of this animation. It is also very useful to be able to place several molecules on the screen at the same time, along with being able to export the images into presentations. The screen controls give energies, and time clocks and allow the user to vary the pace of simulation etc.
2. The associated help page is concise and adequately describes the basic use of the plug-in. The plug-in is very responsive and works pretty much as described. There is both an English and French language version of the plug-in.
1. A small improvement would be to include on the listing of modes the fundamental frequency. It would also be helpful to list on Etot on the screen (perhaps underneath the numbers) what is the zero point, the vibrational contribution, and the rotational contribution to the energy. There is enough real estate on the screen to do this.
Potential Effectiveness as a Teaching Tool
1. The animations present on this site provide a very graphical way of visualizing the simultaneous rotational and vibrational modes of simple molecules. The flexibility of the controls on the animation open up new ways for the student to obtain deep insight into these quantized motions.
2. The plug-in is quite modular and adaptable to different uses; from real-time demonstrations for large audiences in a classroom environment to independent investigation by individual students. The plug-in has some advance features, such as the ability to set up and save multiple pages, which could make it a very effective learning object.
Ease of Use for Both Students and Faculty
The animations load quickly and are quite intuitive in use. The help screen function, operated by clicking on the help button icon (?), is very informative and accurate. An object and a web based help screen are available so that the help information is very detailed indeed. Students could easily use this animation to do quantitative work. It is just a tremendously effective animation.
1. While the interface is well organized, it is a bit cluttered. The "control" modifier key that is required for some features does not work on the Macintosh platform; the "option" key can be substituted in some cases, but not all.
2. The help information on the web side for the applet is a little bit too cryptic for the average user. For example, it is not totally clear how I would export this into an html. The author might benefit by watching a few students try to exercise the various options and making notes as to where they struggle and what is not clear to them (a focus group).