Using the PM3 semiempirical method in HyperChem, treat planar napthalene. First build the molecule, choose SemiEmpirical methods and PM3, and perform a Geometry Optimization. Look in the "Compute>Orbitals" menu to determine the energies of the and LUMO.
What is the wavenumber in cm-1 for the to LUMO transition predicted by PM3?
To find the wavenumber in cm-1 for the to LUMO transition predicted by the PM3 semiempirical method in HyperChem, follow these steps:
1. Build the molecule: Use the molecular drawing tools in HyperChem to construct the planar naphthalene molecule.
2. Choose SemiEmpirical methods and PM3: In HyperChem, go to the "Computations" menu and select "Setup calculation parameters." In the dialog box, choose "SemiEmpirical" as the calculation type and "PM3" as the method.
3. Perform a Geometry Optimization: After selecting the desired calculation parameters, choose the "Compute" menu and click on "Geometry Optimization." This will optimize the geometry of the molecule using the PM3 method.
4. Determine the energies of the and LUMO: After the geometry optimization is complete, go to the "Compute" menu and click on "Orbitals." A dialog box will appear showing the calculated orbital energies. Look for the energy values labeled as (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital).
5. Calculate the wavenumber: The wavenumber is related to the energy difference between and LUMO by the equation ν = (E_homo - E_lumo) * 8065.54 cm-1, where ν represents the wavenumber, E_homo is the energy of the , and E_lumo is the energy of the LUMO. Plug in the energy values obtained from step 4 and calculate the wavenumber.
By following these steps, you should be able to find the wavenumber in cm-1 for the to LUMO transition predicted by the PM3 semiempirical method in HyperChem.