3.3.6.3 Infrared spectroscopy Flashcards
What is infrared spectroscopy?
A pair of atoms joined by a chemical bond is always vibrating
The stronger bonds vibrate faster
Heavier atoms vibrate slower
Every bond has a unique natural frequency that is in the infrared region of the electromagnetic spectrum
When you shime a beam of infrared radiation through a sample
The bonds in the sample can absorb energy from the radiation and vibrate more
However it must be the radiation from the same frequency as th natural frequency
Radiation that emerges from the sample will be missing the frequencies that correspond to the bonds in the sample
What is an infrared spectrometer?
A beam of infrared radiation containing a spread of frequencies is passed through the sample
What is the fingerprint region?
A mass spectrum of many peaks is unique to each chemical
Chemists can match the fingerprint region of a sample on a database
What can the infra-red spectrum be used to show?
If there are any impurities
These are shown if the peaks are different to the fingerprint region of the compound
