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Need help with question 9 plz answer both parts of the question!

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(2 marks) Repeat the calculation demonstrated in the Prelab 2 Video Tutorial with each of the three HF-optimized
molecules from Prelab 1. Then fill in the table below. The first line of the table below has been completed for you -
perform the job yourself and confirm that your results are within 1% of the suggested absorbance wavelength before
continuing with the remainder of the calculations.
Molecule
Theory
Basis set
Job number
Absorbance
Calculation time
Benzene
Wavelength (nm)
(s)
Naphthalene
HF
201.27
25.6
HE
6-31G(d)
94803
Anthracene
HE
6-31G(d)
184242
243. 12
30.1
6-31G(d)
184245
299. 84
69.2
6.
(2 marks) Repeat the calculation demonstrated in the Prelab 2 Video Tutorial with each of the three B3LYP-optimized
molecules from Prelab 1 and fill in the following table. For these calculations, edit the route copied in the Preview pane
to identify B3LYP as the level of theory rather than HF.
Molecule
Theory
Basis set
Job number
Absorbance
Calculation time
Wavelength (nm)
(s)
Benzene
B3LYP
6-31G(d)
1 8 4 252
223.68
39.6
Naphthalene
B3LYP
6-31G(d)
184253
27 7 . 94
129. 3
Anthracene
B3LYP
6-31G(d)
1 84254
378. 49
226.9
7. (2 marks) How does the wavelength of maximum absorbance change as the number of aromatic rings increases? Is this
expected? Explain.
8 .
(2 marks) In Question 4, you used HF and B3LYP to predict the wavelength of maximum absorbance of a single benzene
molecule in a vacuum. To test these predictions, the absorbance spectrum of benzene will be measured in the gas phase.
Write out a stepwise procedure for testing the accuracy of these predictions in the CHEM 211 laboratory. In addition to the
typical equipment available in your basket, you have access to a stoppered cuvette, benzene, and a scanning
spectrophotometer. (Hint: benzene is a volatile liquid)
9. (2.5 marks) The absorption spectrum of benzene vapour is at
right.
a. The measured spectrum demonstrates only
transitions from the ground state to the first
electronic excited state. What do the strong peaks in
Absorbance (A.U.)
230
240
250
260
the absorption spectrum correspond to on a
270
Jablonski diagram?
Wavelength (nm)
b. Refer to your response for Prelab 2 Question 5. Which level of theory (HF or B3LYP) results in a faster
calculation? Which level of theory (HF or B3LYP) results in a more accurate prediction?

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