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Unformatted text preview: ypton, built into the program with approximations to make it possible (called the Hartree-Fock
approximation). In the dialog box that pops up, click the “small” radial button (3-21G). Click
the “options” button, and be sure “RHF” is clicked, and charge is set to 0. The other default
values should be fine (convergence limit 1e-008, iteration limit 50, accelerate convergence
chosen, gradient and MP2 not chosen). Click on “polarizabilities” and be sure “do not calculate”
is clicked. Click on “Configuration Interaction” and be sure “none” is highlighted. Click “OK.”
Click on “Advanced Options.” In the dialog box, be sure “five d orbitals” is chosen. For
“MO initial guess” choose “core Hamiltonian.” Choose “regular” for integral format, and select
“direct SCF calculation.” “Cutoff” should be 1e-010 and buffer size 32000. Click “OK.” Click
“additional basis sets” and be sure “none” is selected. Click “OK” and then “OK” again to close
the setup dialog box.
Go to “Compute” and click on “Single Point.” The system will begin calculating the
electronic configuration for Krypton. You know the calculation is proceeding if “Cancel” is the
only menu option available; it will be the only option that is NOT available once the calculations
are complete. Let this calculation run to completion.
Once the computation is complete, go to “Compute” and choose “Orbitals.” This will
open a dialog box. The shape of the orbitals has already been computed; this is just how you can
bring out the properties of these orbitals. Click and drag the dialog box so you can see the
Krypton atom in the main HyperChem window.
You will notice two radial buttons called “LUMO+” and “HOMO-.” LUMO stands for
“lowest unoccupied molecular orbital;” these are orbitals that have no electrons in them (lowest
means lowest energy), while HOMO stands for “Highest Occupied Molecular Orbital.” Be sure
“3D isosurface” is chosen and “orbital squared” is also chosen.
For the occupied orbitals, put in the appropriate value to complete the table for part III in
the results section. Be sure “HOMO-” is selected and put the appropriate number in the box
below. Then click on “plot.” You need to close the dialog box by clicking “OK” if you want to
Dakota State University Page 99 of 232 Experiment 7: Quantum Mechanics General Chemistry I and II Lab Manual rotate the orbital; just re-open it as previously if you choose to do so. Repeat this for the
unoccupied orbitals, being sure “LUMO+” is chosen. Notice that these orbitals do exist, even
though they are not utilized.
Finally, arrange the shell/subshells from lowest to highest energy from both the occupied
and unoccupied tables. How does this order compare with the order of filling using the Aufbau
15, 14, 13
11, 10, 9
8, 7, 6, 5, 4
2, 1, 0 Shell/subshell
4p Energy Shape* *Notice that inner shells may not appear correct because of approximations and scale.
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