Emission Spectrum & Energy: Exciting Hydrogen Vapor

In summary, by exciting hydrogen vapors with heat or electrical discharges, it is possible to obtain the element's emission spectrum. This is due to the fact that heat and electrical discharges bring a range of energy values to the atom, rather than a single fixed energy value. This is because the energy supplied to the system excites atoms in a chaotic way, resulting in multiple electronic transitions with different energies. This is constrained by quantum mechanics and results in the emission of light at specific wavelengths. Therefore, an electric discharge does not possess a single energy value, but rather brings a range of energies to the atom, resulting in a more complex emission spectrum.
  • #1
pisluca99
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By exciting hydrogen vapors with heat or electrical discharges, it is possible to obtain the element's emission spectrum. In it, as can be seen, appear multiple wavelengths, each corresponding to a particular orbital electronic transition.
From this it can, therefore, be inferred that heat and electrical discharges do not bring a single fixed energy value to the atom, but bring a range of energy values that allow for the different transitions.
How is this possible? Doesn't an electric discharge have a single definite energy value that corresponds to the ∆V between the electrodes? Likewise, does not a given temperature correspond to only one energy value?
 

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The energy supplied to the system excites atoms in a chaotic way to various state of electronic excitation which is an unstable equilibrium. Many different states will be populated but they are constrained to have certain energies by quantum mechanics. These will naturally decay to lower energy emitting light quanta of this characteristic energy.
Of course in a macroscopic population of atoms the excitation and decay are happening concurrently.
 
  • #3
hutchphd said:
The energy supplied to the system excites atoms in a chaotic way to various state of electronic excitation which is an unstable equilibrium. Many different states will be populated but they are constrained to have certain energies by quantum mechanics. These will naturally decay to lower energy emitting light quanta of this characteristic energy.
Of course in a macroscopic population of atoms the excitation and decay are happening concurrently.
And that is clear. But, for example, considering an electric discharge that excites hydrogen atoms, should it not "possess" a single energy value, corresponding to the ∆V between the electrodes?

For example, there is a ∆V of 200 V between the electrodes, which generates a discharge that has an energy of x kJ (totally invented values for the sake of example only). A precise transition may correspond to this energy value, as well as none, depending on the quantization of the energy levels of the atom.

Instead, exciting hydrogen with this discharge results in the emission of more lambdas, indicating that the electric discharge brings to hydrogen not only the energy value x, but also many others, y, z, m, n, etc., to which the different transitions are associated.
 
  • #4
No it should not. The discharge is a wildly chaotic event involving turbulent ionized gas. All energies will be availible including some few larger than 200 eV
 
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FAQ: Emission Spectrum & Energy: Exciting Hydrogen Vapor

What is an emission spectrum?

An emission spectrum is a spectrum of the electromagnetic radiation emitted by a source. It is produced when atoms or molecules transition from a higher energy state to a lower energy state, releasing energy in the form of light. Each element has a unique emission spectrum, which can be used to identify the element.

How is the emission spectrum of hydrogen produced?

The emission spectrum of hydrogen is produced when hydrogen gas is excited by an energy source, such as an electric discharge. The electrons in the hydrogen atoms absorb energy and move to higher energy levels. When these electrons return to lower energy levels, they emit light at specific wavelengths, creating the emission spectrum.

What are the key lines in the hydrogen emission spectrum?

The key lines in the hydrogen emission spectrum are known as the Balmer series, which are visible to the human eye. These lines correspond to transitions of electrons from higher energy levels to the second energy level (n=2). The most prominent lines are at wavelengths of 656 nm (red), 486 nm (blue-green), 434 nm (blue), and 410 nm (violet).

Why is the emission spectrum of hydrogen important in science?

The emission spectrum of hydrogen is important because it provides a fundamental understanding of atomic structure and quantum mechanics. The discrete lines observed in the spectrum were key evidence for the quantized nature of energy levels in atoms, leading to the development of the Bohr model of the atom and later to quantum mechanics.

How can the emission spectrum be used to identify elements?

Each element has a unique emission spectrum, which acts like a fingerprint. By analyzing the wavelengths of light emitted by a sample, scientists can determine the elements present in the sample. This technique, known as spectroscopy, is widely used in fields such as astronomy, chemistry, and materials science to identify the composition of distant stars, chemical compounds, and various materials.

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