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  2. Redshift - Wikipedia

    en.wikipedia.org/wiki/Redshift

    The terms derive from the colours red and blue which form the extremes of the visible light spectrum. The main causes of electromagnetic redshift in astronomy and cosmology are the relative motions of radiation sources, which give rise to the relativistic Doppler effect , and gravitational potentials, which gravitationally redshift escaping ...

  3. Auxochrome - Wikipedia

    en.wikipedia.org/wiki/Auxochrome

    An auxochrome is known as a functional group that produces a bathochromic shift, also known as red shift because it increases the wavelength of absorption, therefore moving closer to infrared light. Woodward−Fieser rules estimate the shift in wavelength of maximum absorption for several auxochromes attached to a conjugated system in an ...

  4. Emission spectrum - Wikipedia

    en.wikipedia.org/wiki/Emission_spectrum

    There are many ways in which atoms can be brought to an excited state. Interaction with electromagnetic radiation is used in fluorescence spectroscopy, protons or other heavier particles in particle-induced X-ray emission and electrons or X-ray photons in energy-dispersive X-ray spectroscopy or X-ray fluorescence. The simplest method is to heat ...

  5. Gravitational redshift - Wikipedia

    en.wikipedia.org/wiki/Gravitational_redshift

    In physics and general relativity, gravitational redshift (known as Einstein shift in older literature) [1] [2] is the phenomenon that electromagnetic waves or photons travelling out of a gravitational well lose energy. This loss of energy corresponds to a decrease in the wave frequency and increase in the wavelength, known more generally as a ...

  6. Bathochromic shift - Wikipedia

    en.wikipedia.org/wiki/Bathochromic_shift

    In spectroscopy, bathochromic shift (from Greek βαθύς (bathys) 'deep' and χρῶμα (chrōma) 'color'; hence less common alternate spelling "bathychromic") is a change of spectral band position in the absorption, reflectance, transmittance, or emission spectrum of a molecule to a longer wavelength (lower frequency). [1]

  7. Fluorescence - Wikipedia

    en.wikipedia.org/wiki/Fluorescence

    Rubies, emeralds, and diamonds exhibit red fluorescence under long-wave UV, blue and sometimes green light; diamonds also emit light under X-ray radiation. Fluorescence in minerals is caused by a wide range of activators. In some cases, the concentration of the activator must be restricted to below a certain level, to prevent quenching of the ...

  8. Spectral line - Wikipedia

    en.wikipedia.org/wiki/Spectral_line

    This is the spectrum of a blue sky somewhat close to the horizon, looking east with the sun to the west at around 3–4 pm on a clear day. A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby ...

  9. Photon upconversion - Wikipedia

    en.wikipedia.org/wiki/Photon_upconversion

    Example of normal Stokes emission through fluorescence (left, red) and anti-Stokes emission (right, blue) through sensitized triplet-triplet annihilation based photon upconversion, samples excited with green light. Upconversion fluorescence. Optical fiber that contains infrared light shines with a blue color in the dark