1. The Dance of the Molecule: An Introduction to Molecular Motion

2. PGCC Sinex Let’s examine the three types of motion possible for a molecule. We will do this in a two-dimensional fashion; however, remember this is a three-dimensional phenomenon. This presentation MUST be viewed in PowerPoint XP.

3. PGCC Sinex Translational motion

4. PGCC Sinex Rotational motion with translational motion only rotational motion translation

5. PGCC Sinex Vibrational motion Stretching of the bond between the atoms

6. PGCC Sinex Vibrational motion Bending of the bond between the atoms

7. PGCC Sinex Describe the types of motion Translational Rotational Vibrational motion that changes the shape of the molecule – stretching, bending, and rotation of bonds whole atom or molecule changes its location in three dimensional space whole molecule spins around an axis in three dimensional space Motion of whole molecule  Motion within molecule

8. PGCC Sinex What about the motion of atoms or ions in solids? In a container of gaseous helium atoms, what type of motion would you observe? In a container of gaseous nitrogen molecules, what type of motion would you observe? Some questions to ponder: What is the difference between internal bond rotation and overall rotation?

9. PGCC Sinex Consequences of motion What type of motion is responsible for collisions? What type of motion is responsible for changing the orientation of a molecule for an effective collision? Are bond angles and bond lengths constant in a molecule? What type of motion is responsible for changing the dipole of a molecule?

10. PGCC Sinex Collisions cause directional changes Collisions and the Possibility of Reaction What is the path of a single atom in a vast number of atoms?

11. PGCC Sinex The torturous path is due to numerous collisions with other atoms.

12. PGCC Sinex Collisions cause reaction This is an effective collision.