Lab Activities

An Introduction to Geometry Optimization


Geometry Optimization Lab Activity

Geometry Optimization Main Page


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


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  • 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

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  • Quick Guide to DISCO Output File

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  • Geometry optimization is a technique used by all computational scientists. It is a method of taking rough geometric approximations and making them as exact as possible. It is a series of iterations performed on the molecule until the energy of the molecule has reached a minimum.

    To begin the process, you must determine an initial geometry, initial basis set and then the chemistry program completes a series of computations. As you have learned in previous lessons, there are three types of calculations that may be performed:

    1. molecular mechanics
    2. semi-empirical
    3. ab initio
    Each of these calculations work to optimize the geometry and depending on which set you use, will determine how exact your optimization will be. These computations not only give you a new geometry, but also a new energy for the molecule. This process is repeated until the molecular energy reaches its minimum. The following flow chart explains the sequence of events which occur in order to optimize a basis set.

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