You will need to bring a jump drive to store your plots.

This experiment will involve the use of the molecular modeling program HyperChem 5.0.  The details of the calculations have been previously discussed in the Physical Chemistry course.

Using HyperChem, calculate the orbital energies for the following molecules:

a) CO - draw the molecule with the correct number of bonds.  Do a molecular mechanics calculation using mm+. This is done by going to SETUP, and choose MOLECULAR MECHANICS.  Once the method is chosen, go to COMPUTE and select GEOMETRY OPTIMIZATION.  When the program is finished with the calculation, do a semi-empirical calculation using pm3.  Again, go to SETUP and choose SEMI-EMPIRICAL.  Select the method of calculation and do a geometry optimization as above. Calculate the orbitals and note the order and energies. This is done by going to COMPUTE and down to ORBITALS.   Include this diagram in your report.  Do these match the MO diagram drawn in class?

Print out the HOMO and the LUMO for CO.

b)  Do the same procedure for N₂ as done for CO (using mm+ for the molecular mechanics and pm3 for the semi-empirical calculation).  Note the orbitals for N₂ and compare to the MO diagram done in class.  Compare the two (CO vs N₂).  Next do the molecular mechanics for N₂ using the program same as before (for CO), but now do the semi-empirical calculations for N₂  using the INDO method.  Note and compare results with the pm3 calculations for N₂ .  Include both MO diagrams for N₂ in your report.

Print out the HOMO and the LUMO for N₂. (both calculations)
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c) Calculate the orbital diagram for F₂ doing molecular mechanics with mm+ and semi-empirical with MNDO.  Compare the results with the expected MO diagram (from class). Include this diagram in your report.

Print out the HOMO and the LUMO for F₂.

Write up
     Each person in the group must submit a separate report.  The report must follow the guidelines on the Lab Report page.  The experimental section will outline the procedure used in modeling the compounds. The results section should include the orbital energy diagrams (4 total - one for CO, two for N₂ and one for F₂) and HOMO and LUMO for the four calculations. Be sure to compare the shapes and energies of the HOMO's for the four plots.   See the plots for HF for comparison.  The discussion section should answer the questions below each part of the experiment.  The MO diagrams from the lecture notes must be included and computer drawn (I suggest either paint or PowerPoint drawings).   This lab will be worth 20 points and is due by 5:00 pm Friday, Feb. 29, 2008. No late reports will be accepted.

CHEM4204 Experiment list