L1 /
14
CH1012
PRINCIPLES
• The electromagnetic spectrum spans a
range of energies. DE = h n Ü n = 104-1020
range of energies. DE = h n Ü n = 104-1020
• Spectroscopy
relies on an instrument
detecting an energy change which is associated with a molecular or atomic change in energy states. DE = E2 – E1= hc/l
Usually a wavelength scale is used.
detecting an energy change which is associated with a molecular or atomic change in energy states. DE = E2 – E1= hc/l
Usually a wavelength scale is used.
Wavelength scales
• UV-Visible
– short-medium wavelength nm
• Infrared –
long wavelength cm-1 mm
• NMR – long
wavelengths MHz (m)
E
E2
E1
