Posted: September 13th, 2017

Conjugated Electrons: Particle in a Box

Paper, Order, or Assignment Requirements

The experiment and requests are in the upload document.

Experiment # 1:  calculations and discussion

Experimental section:

• Give the brand and model of the spectrophotometer used
• Show (as an example) one spectrum

Results A:

Present your results in the same order that you obtained them.  Describe your presentation, do not assume that the reader knows what you are doing.  If you are going to present a Table describe in advance, do the same for a Figure.

Results B:

• Use the band maxima versus N.
• Calculate the length of the polyene (ℓ) using the sum of bond  lengths (C=C = 1.35×10^-10 m and C-C = 1.54×10^-10 m) of a particular polyene.
• Calculate l using the sum of bond lengths (ℓ) and eq. 6.
• Calculate thepolarizabilities
• Calculate the induced dipole moments

Material for discussion:

• Compare l calculated with l
• Calculate the length of the polyene (L) from the experimental wavelengths and eq.6. Compare (ℓ) values with L for each molecule.
• Calculate molecular volumes from (pr² L) to compare with polarizabilities. What is the radius of a Carbon atom?
• Find the real force constant for a C=C bond (eq. 7 without the N).  In this case m is the reduced mass of a C=C bond.  Use 1600 cm^-1 to calculate the frequency (s^-1) of oscillation of a C=C bond.
• Find the permanent dipole moment of a substituted benzene (Atkins) to compare with the calculated induced dipole moments of the experiment.

The comparisons are to determine order of magnitude differences and trends.