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Reaction Dynamics
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Daniel Lacks
Harvard University, Cambridge, MA 02138 |
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Note: |
This program is included in the Advanced Chemistry Collection (SP-28).
To Order Advanced Chemistry Collection |
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Reaction Dynamics simulates collisions of an atom with a diatomic molecule, allowing students to set the initial conditions and the type of atom and molecule and view the molecular collision in several ways in order to discover how microscopic variables affect reaction rates. What conditions lead to a reaction? With Reaction Dynamics, students will find that the probability of reaction depends on the initial energy (it cannot be too little or too much), the distribution of the initial energy between translational and vibrational motion, the direction of incidence of the atom, and the phase of the vibrational motion of the molecule. How does the reaction probability relate to the forces between the atoms? With Reaction Dynamics, the trajectory of the system can be viewed on the potential energy surface defined by the forces between the atoms, so that students will see how the features of the potential energy surface affect the outcome of the collision. Various atoms and molecules can be examined to see how things change with different forces. Isotopes can be substituted, so that the molecular basis of the kinetic isotope effect can be observed. What happens, on a molecular level, to the chemical energy released in exothermic reactions? The disposal of chemical energy can be related to the potential energy surface, and Reaction Dynamics makes clear why, for a certain class of reactions, much of the energy goes into vibrational excitation of the product molecule. This vibrational population inversion is what allows chemical lasers, such as the HF laser, to work. Reaction Dynamics is interactive and allows students to explore new situations on their own. Students can change the initial conditions, masses or potential parameters to see how things change. This type of experimentation can help students understand phenomena more easily than by reading about it in a book or being told about it in a lecture. Also, the graphics and animation capabilities of computers allow clearer and more natural displays of motion than are possible in textbooks. Reaction Dynamics is appropriate for general chemistry and physical chemistry courses, and special topics courses in kinetics or molecular reaction dynamics. Included with the software are sample simulations, accompanied by explanations in the documentation, which demonstrate some of the important concepts of reaction dynamics. Hardware and Software Requirements Reaction Dynamics will run on a Macintosh Plus, SE or SE/30, Classic or Classic II, any Macintosh II, Quadra, or PowerBook. Reaction Dynamics requires System 4.2 and Finder 6.0 or greater. It can be run from an 800K disk drive; a hard disk is not required. Reaction Dynamics is compatible with System 7. |
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Last Updated: July 19, 2001 Created: December 4, 1996 |
Created by: J. L. Holmes Comments to: jceonline@chem.wisc.edu |
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| © 1997 Division of Chemical Education, Inc., American Chemical Society. All rights reserved. | |