# Geometry Optimization Lab Procedure

Home

Geometry Optimization Lab Activity

Geometry Optimization Main Page

#### Students

• Introduction
• Objectives
• Procedure
• Questions
• Further Work
• References/Support Materials

#### Teachers

• Materials
• Standards
• First year chemistry curriculum concepts
• Second year chemistry curriculum concepts

Cartesian Converter Materials

• Z-matrix to Cartesian Converter
• Cartesian Converter Example
• Help Instructions for the Z-matrix to Cartesian Converter

• Overview
• Atomic Orbitals

Lab Activities

• Z-matrices
• Basis Sets
• Geometry Optimizations
• Ionization Energies

Support Materials

• Interactive Tools
• Glossary of Terms
• Quick Guide to DISCO Output File

Developers' Tools

• What's New?
• Discussion Board
• Team Members
• Email the Group

• ChemViz
• Computational Chemistry
• SUCCEED's Computational Chemistry

• Contact Webmaster

• In this lab we will be optimizing the geometry of a water molecule. In order to do this, you will need:
1. Waltz Interface on ChemViz
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.

Developed by
The Shodor Education Foundation, Inc.
in cooperation with the
National Center for Supercomputing Applications

© Copyright 1999-2000 The Shodor Education Foundation, Inc.