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Atomic absorption spectroscopy AAS is a spectroanalytical technique for the quantitative determination of chemical elements employing the absorption of light by ______ atoms in the gaseous state.
free
In analytical chemistry, this technique is used for determining the concentration of a particular element in a sample to be analyzed by ______ the light.
absorbing
What happened when atoms ______ the light.
absorb
Atoms undergo only ______ transition, no vibrational or rotational transitions.
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The linewidth of an atomic line is defined as its width in wavelength units when measure at one half the maximum ______.
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Explain the principle behind atomic absorption spectroscopy.
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What causes the sharp absorption peaks in sodium vapor at 589.0 and 589.6nm?
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What is the nature of broadening observed in atomic absorption spectroscopy?
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What is the definition of linewidth in atomic absorption spectroscopy?
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Which types of transitions do atoms undergo when they absorb light in atomic absorption spectroscopy?
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Study Notes
Atomic Absorption Spectroscopy (AAS)
- AAS is a spectroanalytical technique used for the quantitative determination of chemical elements.
- It involves the absorption of light by free atoms in the gaseous state.
Principle of AAS
- Atoms absorb light and undergo electronic transitions, but not vibrational or rotational transitions.
- When atoms absorb light, they exhibit characteristic absorption peaks.
Example: Sodium Vapor
- Sodium vapor exhibits two sharp absorption peaks at 589.0 and 589.6 nm due to excitation of 3s electrons to two 3p states.
Linewidth
- The linewidth of an atomic line is defined as its width in wavelength units when measured at one half the maximum signal.
- There are two types of broadening that affect the linewidth: Natural Broadening and Collisional Broadening.
Natural Broadening (Uncertainty Effect)
- The lifetime of the excited states leads to uncertainty.
- A lifetime of 10^(-8) seconds leads to a width of 10^(-5) nm.
Collisional Broadening (Pressure Effect)
- Collisional broadening occurs due to the collision of the emitting/absorbing species with other atoms/ions in the heated medium.
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Description
Test your knowledge of Atomic Absorption Spectroscopy (AAS) with this quiz! Learn about how atoms absorb light and explore the application of AAS in determining the concentration of sodium in a sample.
