CHM247H1 Chapter Notes - Chapter 12: Adsorption, Diastereomer, Toluene
Document Summary
Irradiation of organic molecules with light of wavelength ( ) 2. 5 m to 25 m causes bond vibtations to occur. Chapter 12: structure determination: mass spectrometry and infrared spectroscopy. This is within the infrared portion of the electromagnetic spectrum. This region is commonly expressed as a wavenumber range (1/ ) 2. 5 m to 25 m represents 2. 5 x 10-4 to 2. 5 x 10-3cm. Wavenumbers often quoted as reciprocal of wavelength in cm. Wavenumber ranger in which infrared energy absorption is observed is 400 to 4000 cm-1. Covalent bonds continuously vibrate like two atoms joined by a spring. Energy of these vibrations is quantized only specific vibrational energy levels allowed in a molecule. Energy of a particular vibration given by: e = h , = bond vibrational frequency. When frequency of applied infrared radiation matches that of bond vibrational frequency, an absorption is observed. This is noted by a dip in infrared spectrum.
