CHM138H1 Chapter all: Infrared Spectroscopy and Mass Spectrometry

• School: UTSG
• Department: Chemistry
• Course: CHM136H1
• Professor: all

Document Summary

Note: some key concepts to understand before this subject include quantum mechanics, If a photon has exactly the right energy it can promote vib ra tio n a l e xc ita tio n which means a bond absorbs it temporarily. S ection 15. 2: ir s p e c tro s c o p y: vibrational excitation displays stored energy in different ways, e. g. s tre tc h in g , b e n d in g . Smaller atoms vibrate at higher frequencies because mass is lower - thus c-h bond have the highest wavenumber. This region is compound specific and difficult to read: a c o n ju g a te d (a pi bond separated by one sigma bond) bond will produce a lower energy signal than an unconjugated bond. Crc bonds usually produce weak signals: when some bonds vibrate they produce no dipole moment for ir radiation to interact with, symmetrical crc (alkenes, symmetrical triple bonds.