JCE Software, 7C1: MolVib 2.0

MolVib 2.0

Daniel Huber
Metrohm, Ltd., CH-9100 Herisau, Switzerland
Paul Wagner
University of Wisconsin-Madison, Madison, WI 53706-1396

Note:
This program is included in both the General Chemistry Collection (SP-16) and the Advanced Chemistry Collection (SP-28).

To Order General Chemistry Collection
To Order Advanced Chemistry Collection

MolVib 2.0 is an update of a program previously published by JCE: Software (1). The new version is System 7 compatible and includes color graphics and other interface improvements.

Animation of the asymmetric stretching of ammonia. Click image to view QuickTime video.

MolVib allows you to display a vibrating molecule on your computer screen and view it from whatever position you choose. You can choose one of several molecules available as examples and then select each normal vibrational mode from a menu. Modes may be animated individually, or mixed to demonstrate the equivalence of degenerate vibration. Animation speed can be varied in order to see the motion more clearly, and the molecule can be rotated in three dimensions so that the vibration can be observed from any viewpoint.
Center-of-mass and Eckhard (angular momentum) conditions are always fulfilled during the motion so that mass effects such as isotopic substitution can de demonstrated. H₂O, HDO and D₂O can easily be compared, for example. In addition to the graphic output, you can obtain numeric results for each vibration.
MolVib can be used appropriately at several levels. For introductory students it provides a convenient way to illustrate how molecules vibrate and to show difference in vibrations when isotopic substitutions are made. At a more advanced level it is possible to show that if a subsection of a molecule has a very different vibrational frequency from the frequencies in the rest of the molecule, that vibrational mode will survive even in the composite molecule. In physical chemistry and other advanced courses it is possible to examine eigenvalues and eigenvectors for a given vibrational problem, and these could be compared with results of students calculations.
Hardware and Software Requirements
Software in Series C of JCE: Software requires an Apple Macintosh computer with a hard drive and a SuperDrive floppy disk drive. System software version 6.0.7 or later is required. If you are running System 7 or MultiFinder, at least 2 MB of RAM is required. In addition MolVib 2.0 requires a Macintosh II or better, System 7 or higher, and at least 4 MB of RAM. A 256 color monitor is not required, but strongly recommended.
Installation of MolVib requires approximately 200 KB of free hard disk space.
Literature Cited

Huber, D. MolVib, JCE: Software, 1991, 3C(1).

First Published: July 1995
Citation: Huber, D.; Wagner, P. . MolVib 2.0 J. Chem. Educ. Software 7C1
Keywords: Lecture Aid; Computer Room; High School; General; Analytical; Organic; Physical; Molecular vibration animations; Normal modes

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Last Updated: July 19, 2001
Created: December 4, 1996 Created by: J. L. Holmes
Comments to: jceonline@chem.wisc.edu

© 1997 Division of Chemical Education, Inc., American Chemical Society. All rights reserved.



MolVib 2.0
Daniel Huber Metrohm, Ltd., CH-9100 Herisau, Switzerland Paul Wagner University of Wisconsin-Madison, Madison, WI 53706-1396

Note:	This program is included in both the General Chemistry Collection (SP-16) and the Advanced Chemistry Collection (SP-28). To Order General Chemistry Collection To Order Advanced Chemistry Collection

MolVib 2.0 is an update of a program previously published by JCE: Software (1). The new version is System 7 compatible and includes color graphics and other interface improvements. Animation of the asymmetric stretching of ammonia. Click image to view QuickTime video. MolVib allows you to display a vibrating molecule on your computer screen and view it from whatever position you choose. You can choose one of several molecules available as examples and then select each normal vibrational mode from a menu. Modes may be animated individually, or mixed to demonstrate the equivalence of degenerate vibration. Animation speed can be varied in order to see the motion more clearly, and the molecule can be rotated in three dimensions so that the vibration can be observed from any viewpoint. Center-of-mass and Eckhard (angular momentum) conditions are always fulfilled during the motion so that mass effects such as isotopic substitution can de demonstrated. H₂O, HDO and D₂O can easily be compared, for example. In addition to the graphic output, you can obtain numeric results for each vibration. MolVib can be used appropriately at several levels. For introductory students it provides a convenient way to illustrate how molecules vibrate and to show difference in vibrations when isotopic substitutions are made. At a more advanced level it is possible to show that if a subsection of a molecule has a very different vibrational frequency from the frequencies in the rest of the molecule, that vibrational mode will survive even in the composite molecule. In physical chemistry and other advanced courses it is possible to examine eigenvalues and eigenvectors for a given vibrational problem, and these could be compared with results of students calculations. Hardware and Software Requirements Software in Series C of JCE: Software requires an Apple Macintosh computer with a hard drive and a SuperDrive floppy disk drive. System software version 6.0.7 or later is required. If you are running System 7 or MultiFinder, at least 2 MB of RAM is required. In addition MolVib 2.0 requires a Macintosh II or better, System 7 or higher, and at least 4 MB of RAM. A 256 color monitor is not required, but strongly recommended. Installation of MolVib requires approximately 200 KB of free hard disk space. Literature Cited Huber, D. MolVib, JCE: Software, 1991, 3C(1).


News \| Issues \| CD-ROM / Video \| Find It! \| Technical Support \| For Authors
JCE Online \| Journal \| Software \| Internet \| Happenings \| About JCE \| Contact JCE

Last Updated: July 19, 2001 Created: December 4, 1996	Created by: J. L. Holmes Comments to: jceonline@chem.wisc.edu

© 1997 Division of Chemical Education, Inc., American Chemical Society. All rights reserved.