General features of spectroscopy
Start with the big picture
Optical spectroscopy probes energy-level transitions by measuring the absorption, emission, or scattering of radiation. Absorption occurs when photon energy matches the gap between quantized states; emission releases energy as photons, including through fluorescence or phosphorescence. The topic connects these processes to molecular transitions and chromophores, then introduces quantitative interpretation through the Beer–Lambert law and molar absorptivity. It also covers selection rules and practical spectral characteristics: line width, resolution, sensitivity, and signal-to-noise ratio. Fluorescence and phosphorescence are distinguished by their pathways and timescales, while Raman scattering and circular dichroism extend the range of optical techniques. Together, these foundations support the interpretation of spectroscopic measurements in chemistry and photobiology.
What you'll learn
- Explain how spectroscopy probes transitions between quantized energy states.
- Distinguish absorption, fluorescence, and phosphorescence.
- Describe the Beer–Lambert relationship and the meaning of molar absorptivity.
- Identify how selection rules and spectral characteristics affect measurements.
- Recognize the roles of Raman scattering and circular dichroism.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
