The focus of this semester's lab program will be to utilize various spectroscopic and computational techniques to investigate molecular structure and properties. Many of the experiments will utilize techniques for which there is only one instrument available. Groups will schedule time to collect data at some point during the week when it is not being utilized by other groups or courses.
1. Spectrum of a Particle in a Box - Exp #34, p.687
The diode array spectrometer will be used to measure absorbance maxima of a series of methine dyes. These will be compared to results expected from a FEMO "particle in a box" model reported in the literature for these compounds. Students will then conduct semi-empirical MO calculations to compare the HOMO-LUMO energies for these dyes.
2. Ab Initio Determination of Ionization Energies for Various Elements
The predicted ionization energy for a series of elements will be calculated using various QM computational techniques. These will be compared with literature values and with computational requirements.
3. Vibration-Rotation Spectra of a Diatomic Molecule
The Nicolet FT-IR spectrometer will be used to measure the rovibrational spectra of HCl. A number of molecular parameters will then be calculated..
4. Determination of Molecular Properties using ab initio calculations.
5. Electronic Spectrum of Iodine
The dual-beam UV/Vis spectrometer will be used to measure the spectrum of iodine; from these the dissociation energy and other parameters will be determined.
6. Internal Rotation N,N-dimethylacetamide using Spartan
Students will use Spartan to generate a predicted PE curve as a function of dihedral angle to characterize internal rotational barriers. 7. Internal Rotation rates for N,N-dimethylacetamide.
A Jeol 300MHz NMR with variable temperature probe will be used to evaluation the NMR spectra over a range of temperatures.
8. Viscosity of Solutions of Macromolecules - Exp #14, p.522.