Infrared spectroscopy Flashcards
What is this technique used for?
To identify compounds based on changes in vibrations of atoms when they absorb IR of certain frequencies
What does a spectrophometer do?
Irradiates sample with EM waves in infrared region
What does a spectrophometer do once it has irradiated the sample?
Detects the intensity of the wavelength of IR radiation which goes through the sample
Do all organic molecules absorb IR radiation?
Yes
What will happen to bonds between atoms when they absorb IR radiation?
Depending on which energies of radiation are absorbed, bonds will vibrate by stretching, bending and twisting
Will organic molecules always vibrate?
No - only at a specific frequency
What is the resonance frequency?
The specific frequency at which the molecules will vibrate to stimulate larger vibrations
What is the wavenumber?
Depeneding on the rest of the molecule, each vibration will absorb specific wavelengths of IR radiation
What is the wavenumber also shown as?
The reciprocal of the wavelength (cm^-1)
What do particular abosrbances have?
Characteristic widths (broad or sharp)
Intensities (strong or weak)
How can different functional groups be identified?
By comparing its IR spectrum to the IR spectrum of a known compound
