CHM 4412 – SPRING 2009

COMPUTER PROJECT

Organize a working group of three members, at least one of whom should be familiar with the Microsoft Windows operating system. Each student should undertake the computer project as a personal activity.

 

The project consists of doing computational chemistry calculations using the HyperChem software. It can be downloaded as explained below, or used as available in computing servers in the Chemistry department or the Quantum Theory Project.

 

To download an evaluation version of the HyperChem software, useful for 10 days, do the following.

 

Go to the www.hyper.com web site; go to “products”; go to “Student HyperChem”, go to “evaluation”. Following instructions, download and install the software. Follow instructions on how to activate it. You’ll have 10 days to explore and use the program after you receive a license file.  

 

You may want to read the online tutorials first. Calculations can be performed at a personal PC or laptop after the computational software has been installed.

Each member of the group should:

  • a) Choose a molecule with 3 to 6 atoms from H to Ne.
  • b) Obtain its equilibrium conformation, and the properties listed below.
  • c) Calculate the energies of its HOMO and LUMO.
  • d) Tabulate the results or print the output files of the computations.

To use HyperChem, consult the book "Getting Started" by Autodesk, Inc., or the online tutorial that comes with the software. You can practice taking the lessons 1 (Getting started), 2 (Basic Drawing), 3 (Creating small molecules), 4 (Moving Molecules), 9 (Minimizing Energies), and 11 (Molecular Orbital Calculations).

If you are using a Chemistry or QTP computer, save your own files in a new directory designated as CHM 4412S09, under your surname. Delete your files after you finish your project.

1. Calculations for polyatomics.

Select a polyatomic of your choice with atoms from H to Ne; it can be neutral or ionic, and a singlet or multiplet state.

  • a) Choose from the File menu the option "Start log" to create a "chem.log" file recording your calculations as you perform them. Use the drawing tool and the "Build" menu to create your molecule.
  • b) Use the Setup menu to optimize the molecular conformation with "Molecular Mechanics" (MM) to start with.
  • c) Use Setup again and choose "Semi-empirical" to calculate molecular orbitals with INDO; then choose "Single Point", "Graph", "Orbital" and either "HOMO" or "LUMO".
  • d) Read the chem.log file and record only the final conformation (bond distances and angles), total and binding energy, atomic charges and electric dipoles, and the energies of the HOMO and LUMO.

2. Report.

Write a brief report (three or more pages, with your name) about your molecule, including the following information.
a. Sketch your molecule with atomic labels, bond distances and angles, and its orientation in an (xyz)-frame.
b. Give the equilibrium binding energy, in kJ/mol.
c. Give the tables of atomic charges and dipole moments, indicating the units.
d. List energies of the HOMO and the LUMO in eVs.
The printout from the log file, with your annotations, would be sufficient. Edit the chem.log file (which can be quite large) to shorten it and to show only the information requested. The report can contain figures of the molecule and HOMO and LUMO orbitals, but these are not required.

Access to computers and software.

You can do this work in any computer which has installed HyperChem. It can also be purchased or used on trial from the company Hypercube (URL www.hyper.com), and installed in your personal computer.

A place with an available PC and the software is the computational chemistry Lab on the third floor of the Chemistry Lab Building; there you need to reserve time with the Physical Chemistry secretary, Vivian Thompson.