The document presents an overview of atomic line width and the uncertainty principle, detailing the definition, significance, and sources of line broadening that affect atomic absorption and emission spectra. It highlights that narrow lines are crucial for reducing interference in spectroscopy and discusses various factors like the uncertainty effect and the Doppler effect that contribute to line broadening. Ultimately, it underscores the importance of understanding these concepts for the design of instruments used in atomic emission spectroscopy.

1. Presentation On:
Atomic Line width &
Uncertainty principle
• Definition
• Profile Of an atomic line
• Importance Of Atomic line width
• Sources of line broadening
• Uncertainty principle
Contents:
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2. Atomic Line Width
• Line width or effective line width of an atomic absorption or emission line is
defined as its width in wavelength unit when measured at one half of the
maximum signal.
• An atomic line should have small(or zero) line width since transition between
two quantum states requires an exact amount of energy.
• Several phenomena however cause line broadening so that all atomic lines
have finite width.
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3. Profile of an atomic line:
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4. Importance of atomic
line width:
• Width of atomic line are quite important in atomic spectroscopy
• Narrow lines in atomic and emission spectra reduce the possibility of
interference due to overlapping line.
• Line width are extremely important in the design of instruments for
atomic emission spectroscopy.
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5. Sources of line
broadening:
• The uncertainty effect
• The Doppler effect
• The pressure effect
• Electric & magnetic field effect
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6. Line broadening from
the uncertainty effect:
• Spectral lines always have finite width because the life time of one or both
transition states are finite, which leads to uncertainties in the transition times
and to line broadening as consequence of the uncertainty principle.
• Transition between two states would approach zero only if the life time of two
states approached infinity.
• Although the lifetime of a ground states electron is long, the lifetimes of
excited states are generally short( typically 10^-7 to 10^-8 sec)
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7. Example:
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8. Solution:
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9. Thank you!!
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