3. Atomic Absorption Spectrometry Hollow Cathode Lamp Graphite Furnace Slit Monochromator Slit Detector Atomic Absorption spectroscopy involves the study of the absorption of radiant energy by neutral atoms in the gaseous state.3. Atomic Absorption Spectrometry Hollow Cathode Lamp Graphite Furnace Slit Monochromator Slit Detector Atomic Absorption spectroscopy involves the study of the absorption of radiant energy by neutral atoms in the gaseous state