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Introduction to Spectroscopy and Its Types

May 14, 2025

Spectroscopy 101: Types of Spectra and Spectroscopy

Introduction to Spectroscopy

  • Spectroscopy is the study of how different materials emit and interact with light at different wavelengths.
  • It helps determine the temperature and composition of objects without direct sampling.

Visualizing Spectra

  • Light is separated into component colors using prisms or diffraction gratings to form a spectrum.
  • Spectroscopes and spectrographs are tools used to capture and measure spectra.
  • Spectra can be represented as images or graphs showing brightness vs. wavelength.
  • Graphs reveal subtle color differences not visible to the naked eye.
  • Example: Spectrum of star Altair, showing emission and absorption lines.

Types of Spectra

  • Continuous Spectrum: Contains all wavelengths; emitted by hot, dense objects.
    • Blackbody curve is a type of continuous spectrum.
    • Useful for calculating temperature based on peak wavelength.
  • Emission Spectrum: Shows colored lines emitted by a glowing gas.
    • Corresponds to specific atoms and their light emission patterns.
    • Useful for studying hot gas clouds and their composition.
  • Absorption Spectrum: Continuous spectrum with missing colors, shown as black lines.
    • Occurs when light passes through gas, with atoms absorbing specific wavelengths.
    • Helps identify elements in gas by their unique absorption lines.

Relationship Between Spectra

  • Continuous, emission, and absorption spectra can be visualized together.
  • Light interaction with gas can lead to absorption or heating, causing emission.
  • Spectra types are interconnected; absorption and emission lines have inverse relationships.

Reflectance Spectra

  • Reflectance spectra show colors reflecting off a surface.
  • Used to study Earth and planetary surfaces, determining material composition.
  • Reflectance spectra are complex, influenced by many factors like surface texture.

Naked-Eye Spectroscopy

  • Human color vision uses basic spectroscopy principles to distinguish materials.
  • Differences in color perception in daily life are a result of light absorption and reflection.

Summary

  • Spectroscopy provides detailed insights into the universe by analyzing how light interacts with matter.
  • Different spectra types offer unique information about temperature, composition, and material characteristics.

Last Updated

  • July 07, 2022