Spectroscopy

Full Spectrum

Hydrogen Emission
/Absorption Spectrum

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Place your mouse over the image to see the absorption spectra

Full Spectrum

Helium

 Emission/Absorption 
Spectrum

Place your mouse over the image
to see the absorption spectra

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Every Energy level transition creates a single spectral line

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"Science of the Silicon Solar Cell"

Don Ion

How many different spectral lines can be produced
by an atom with 5 energy levels?

Answer

10 Spectral Lines

10 colors

10 frequencies

10 photons

Black Body Radiation Results:

1. Only the high energy objects gave off colors on the violet side of the spectrum 

2. Electrons in atoms are not capable of giving off all colors (energies)

3. Each element gives off a unique pattern of colors called a 'bright line spectrum'.

This knowledge is very useful to chemists and other scientists. Why?

Answer

 1. Spectral lines used to:

• identify unknown elements.

• determine the composition of distant stars

To Identify an Unknown Element

- Electrify, Heat it up and analyze its colors.

- Compare emitted colors to a database of elemental spectral lines

The diagram below represents the bright-line spectra of four elements, A, B, C, and D, and the spectrum of an unknown gaseous sample.

Based on comparisons of these spectra,
which two elements are found
in the unknown sample?

Jan 2006

B and C

What are stars made of ?

Bohr's Conclusions