slideshare ppt on research

Tuesday, 26 February 2013

Photo luminescence

Photo luminescence

• Molecules that have an electronic excitation are excited

• Molecules that have a vibration excitation are hot
• With light absorption, molecules may become hot and excited
• Physical process that leads to excited molecules can be
  physical(e.g. absorption of light), mechanical (e.g. friction),
  or chemical(e.g. reactions)
• When excited molecular states decay back to the ground
  state,resulting in the emission of light, they are undergoing a
  luminescence process
• Generation of excited molecules by light absorption, that then
  decay emitting visible light, is photo luminescence
• Photo luminescence processes are divided into 2 classes:
     – Fluorescence and Phosphorescence