This experiment explores isotopic substitution as a method to identify stretching frequencies and linking experimentally determined parameters with theoretical predictions utilizing a simple harmonic oscillator obeying Hooke’s law.
Students will use IR spectroscopy and isotopic substituion in order to predict theoretical frequency shifts in IR spectra of an O-H bond.
Students will synthesize their results into an organized and coherent lab report as described in the student instructions.
CH3OH and CH3OD
If you are using this in a sophomore level class, it will be important to spend time discussing organic functional groups and where they show up in the IR spectra. I also spend time discussing correlations between bond strengths and bond lengths and how these are related to IR stretching frequencies. Importantly, any isotopically substituted molecule would work so that an analysis of different types of organic functional groups would enhance this lab.
Students should be able to generate a formal lab report and detail methods of isotopic substitution for frequency determination. They will showcase their experimental data and compare to their theoretical prediction. They will need to be very clear about how they calculated their theoretical frequency.