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Showed that what light can be dispersed into a continuous range of colours.
He introduced the word 'spectrum' to describe the phenomenon.
To observe this phenomenon, he used a device that consisted of:
- a small aperture to let a beam of light through
- a lens to collimate that light
- a glass prism to disperse it
- a screen to display the resulting spectrum -
Improved Newton's 'crude' spectrometer by including a
lens that captured sunlight as a spectrum.
He qualitatively observed the 'gaps' or
the missing sections of colour. -
Fraunhofer quantitatively analysed spectra from the sun,
when sufficiently dispersed, had large number of fine dark lines-
now known as Fraunhofer lines. This was the first time that spectral lines were observed and analysed quantitatively. He also studied spectra of stars and planets. -
Invented the modern spectroscope.
Found elements had their own unique spectra.
Laid the foundations for stellar spectroscopy. -
Published a study on the wavelengths of solar spectral lines.
He expressed these in units of 10^-10 m. This new unit known as 'angstrom (Å)'.
Considered to be one of the fathers of modern spectroscopy -
Discovered the element Helium (from the Greek word 'Helios') when analysing solar spectra. Its presence was not detected on Earth previously.
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Produced first diffraction grating
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Measured infrared spectra using photographic plates
Correctly predicted that absorption patterns were related to chemical composition of sample -
Improved gratings by making curved diffraction grating at John Hopkins University.
Gratings from his lab became the worldwide standard. -
Shows that visible spectral wavelengths of hydrogen can be represented by a mathematical formula.
The lines are known as the Balmer series of hydrogen. -
Generalises Balmer series
Introduces Rydberg's constant to describe the visible wavelengths of hydrogen -
First started work on time-resolved optical emission spectroscopy.
This involves moving photographic film into the focal plane of
spectrograph. -
Created first mass spectrometer (previously known as parabola spectrograph)
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Father of X-ray spectrometry
Moseley's Law: showed how the unique X-ray spectra of atoms and how it depended on thee atomic number of element -
Produced first evacuated spectrograph for identifying sulfur
and phosphorus in steel. -
Develops the Heinsenberg uncertainty principle that
explains the broadness of spectral lines -
Developed an analytical technique where scattered light is obtained to determine the vibrational energy patterns of a given sample
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Producer of first commercial grating spectrograph
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Developed atomic absorption spectroscopy
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