Quantum Chemistry 6.7 - Microwave Spectroscopy Example

[@marchans-christianpiech3297]

Thank you so much for this video, you are literally helping whole class of 2nd year chemists pass one nothing short of a hell subject :D

[@skeivys]

great explanation

[@TMPChem]

And a very common problem that shows up in many a pchem test.

[@nkyu3035]

just out of curiosity, how are the wavenumber of photon that absorbed or emitted measured?

[@TMPChem]

Inside of a spectrophotometer there is a light source which emits photons across a range of frequencies. These photons then pass through a monochromator (either a prism or a very fine grate) which separates each frequency of photon into a slightly different angle of travel. A single frequency is chosen by passing the light through a very small aperture, which allows only a very small range of frequencies to pass through, which then hits the sample. A bunch of other stuff happens to allow you to record what percentage of the initial signal intensity passes through the sample, allowing you to calculate transmittance. There is typically some moving part which allows you to select the desired wavelength of light (often by rotating the monochromator), and by scanning across all frequencies in a range you can obtain a full spectrum.

[@nkyu3035]

much appreciated.