Emission spectrum Definition and 66 Threads

The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances.

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  1. C

    Emission Spectrum - Does Energy Always Transfer in Photon Form?

    Hi all I'm unsure about something and so would like to pose the following question. When an electron moves to a lower state it emits energy in the form of a photon. But in order to get excited into this higher state it must first receive a minimum amount of energy. Is the energy received...
  2. J

    How Does Voltage Affect the X-ray Emission Spectrum of Molybdenum?

    About the intensity of x-ray emission spectrum of Molybdenum as a function of wavelength for various applied voltages: Explain fully: 1) the production of continuous radiation emitted 2) the absence of radiation of wavelength shorter than the minimum wavelength 3) the presence of the...
  3. P

    Emission Spectra of Elements: List & Resources

    I was just wondering if anyone knew of anywhere on the internet that had a list of all known emission spectrums of the elements. Thanks!
  4. I

    What Temperature is Needed for Hydrogen Gas to Produce a 656.2nm Emission Line?

    the question states that the emission spectrum of hydrogen contains a line with wavelength 656.2nm. and we need to approx find out what temp the H gas needs to have to be heated before this line appers in the spectrum i have worked out that for this wavelength the electron mov from level 3 to...
  5. T

    What is the Earth's emission spectrum as seen from outer space?

    Hello, Does anybody know if there has ever been an emission spectrum of Earth recorded by one of our spacecraft s after launch from outer space? When we directly image extrasolar planets we are able to determine their atmospheric properties, etc, so can someone point me to a link which...
  6. J

    Why Is the Balmer Series More Commonly Seen than Other Hydrogen Emission Series?

    I keep seeing the hydrogen emission spectrum from the Balman series (when an electron falls to n=2). It's all over my textbook. Why don't I ever see the Lyman series or any other series? Is it really rare for hydrogen electrons to fall to energy levels other than n=2?
  7. E

    Specific parts of the emission spectrum of a sodium lamp

    Homework Statement Part a) The emission spectrum for Sodium lamp contains a reasonably bright red line in its spectrum. What is its origin? Part b) The possible transitions between electron energy levels for Sodium were analysed. There were no transitions between the s series (s subshell)...
  8. E

    What is the origin of the strong red line in the sodium emission spectrum?

    I was doing an undergrad experiment on the sodium emission spectrum and I have a few queries. Of course, I was asked to analyse the famous yellow doublet which I'm on top of. I was also asked the analyse the diffuse series which was fine too. What I did notice however, was a strong red line...
  9. P

    Emission Spectrum of elements other than Hydrogen

    *This isn't actually coursework but i was under the assumption that questions go to this forum* Homework Statement Hi, for while I've been under the impression that spectral lines of all the elements can be calculated. I did some research and found that there is a simple equation (Rydberg...
  10. I

    How could vary the Helium emission spectrum?

    In a condition of high pressure, how could vary the Helium emission spectrum? Is this spectrum modified from the pressure?
  11. B

    Comparing Emission Spectrum of Moving & Stationary Hydrogen

    Homework Statement Ok guys, Helping my girlfriend out once again. She(if you haven't seen this before) is in Physics 101...yet, I(have taken all engineering courses) can't figure these out. Their book is absolutely terrible! Please give an answer that I can understand(as I like to learn...
  12. C

    How Do You Calculate Additional Wavelengths in an Emission Spectrum?

    I solved a, but I couldn't figure out b... I've tried different combinations but nothing turned out correctly... Homework Statement The emission spectrum of an unknown substance contains lines with the wavelengths 172 nm, 194 nm , and 258 nm, all resulting from transitions to the ground...
  13. N

    Identifying an element from Emission Spectrum

    Using data collected from a spectrometer, with a diffraction grating of 100 lines/mm, I have collected a set of data. From this I have calculated wavelengths for the 1st and 2nd order lines of the three brightest visible colors, which were Blue/Violet, Green, and Orange. To complete my lab I...
  14. E

    How Can the Emission Spectrum of a Gas Be Manipulated?

    Is there anyway of manipulating the emission spectrum of something like a gas by pumping it with a specific input? An argon gas laser, for example, will have lots of emission lines. Is there anyway of singling out groups of those lines without changing the gas? I would imagine such a method...
  15. A

    Why is the Emission Spectrum the same every time?

    I'm confused So the atoms becaome excited by absorbing energy, like from a hot flame, so this energy makes an electron (or is it all electrons) in the outer shell (or is it all the shells) move to a higher energy level and when the electron(s) return to its(their) ground state, they give off...
  16. G

    How to measure an emission spectrum?

    Say I have a spectrophotometer that has a grating monochromator. If I want to measure emission instead of absorption from a lamp, could I just remove the exit slit? By removing the exit slit, doesn't all of the light just hit the sample?
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