Geometry Optimization Lab Procedure

Geometry Optimization Lab Activity

Students

1. Waltz Interface on ChemViz
2. Spreadsheet
3. Z-Matrix Converter

Procedure

1. On your spreadsheet, create two columns, one titled "Bond Angle" and the other "Energy." In your "Bond Angle" column, list the angles beginning with 180 degrees and decreasing in increments of 10 until you get to 90 degrees.
   

2. Next, determine an initial geometry for a water molecule. Do this by first placing the Oxygen atom at (0,0,0) and then determining the initial bond lengths.
3. Put this initial geometry into the Z-Matrix converter and determine the Cartesian Coordinates for your molecule.
   

4. Now, use the Waltz Interface in ChemViz to calculate the energy of this molecule.
5. Repeat steps 2-4 for different angles ranging from 90-180 degrees in increments of 10 degrees.
6. Save your results in the spreadsheet you already created.
7. Once you have collected all your data, graph your results as a connected scatter plot. Put the 'Angle' values on the x-axis and 'Energy' values on the y-axis.
8. Using your graph, estimate the minimum of your line plot. Narrow your range (angle values) and repeat steps 1-7 with angles decreasing in increments of 1 in order to find the most accurate angle that optimizes the water molecule geometry.