Equation for modeling atomic spectra of all atoms

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Discussion Overview

The discussion revolves around the equations used to model atomic spectra, particularly questioning whether a general equation exists for all atoms or if it is limited to hydrogen and its isotopes. Participants explore the implications of quantum mechanics on atomic spectra and the complexity involved in deriving a universal formula.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that the equation discussed is specific to hydrogen and approximately applicable to Rydberg states.
  • There is a question about whether atomic spectra are the same for all isotopes, leading to a discussion on isotope shifts.
  • One participant mentions that the isotope shift occurs due to the motion of the nucleus affecting the wavefunction and energy levels of electrons.
  • A formula for the isotope shift is presented, involving the reduced mass and energy levels.
  • Another participant suggests that quantum mechanics introduces probabilities, complicating the derivation of a general result for multielectron atoms.
  • In contrast, another participant argues that the lack of a general result is due to the complexity of the systems rather than the probabilistic nature of quantum mechanics.

Areas of Agreement / Disagreement

Participants generally agree that the equation is specific to hydrogen and that no general expression for all atoms has been derived. However, there is disagreement regarding the reasons for the absence of a universal formula, with differing views on the role of quantum mechanics and complexity.

Contextual Notes

Limitations include the lack of a comprehensive understanding of multielectron atoms and the dependence on specific conditions for isotopes. The discussion does not resolve the complexities involved in modeling atomic spectra for all atoms.

Xilus
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I've seen the equation I think is just for hydrogen. is this just for hydrogen?
energy_hydrogen.png

of course this doesn't return the atomic spectra, it returns the energy.
So using E=h*v and Planck's constant. a simple factor of 1/h would return the frequency.
right? Energy is directly proportional to frequency.
and E0=13.6eV n1<n2 where both n1 and n2 are integers

Is there an equation that models atomic spectra of all atoms?
 
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Xilus said:
is this just for hydrogen?
Yes it's only for hydrogen, and approximately for the so-called Rydberg states.

Xilus said:
So using E=h*v and Planck's constant. a simple factor of 1/h would return the frequency.
right?
Yes.

Xilus said:
Is there an equation that models atomic spectra of all atoms?
As far as I know, no. We haven't derived the general expression for energy levels for all atoms.
 
is the spectra the same for all isotopes?
 
Xilus said:
is the spectra the same for all isotopes?
There is the so-called isotope shift which arise due to the fact that the nucleus is not completely at rest. It moves around by a very little amount which in turn disturbs the motion and hence wavefunction and energy levels of electrons. Different nuclear mass will have different effect on the wavefunction.
 
The formula for the isotope shift is quite simple. It's just a scaling by the reduced mass.
The energy is
$$E_M = \frac{M}{m_e+M} E_\infty \left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)$$
where ##m_e## is the electron mass, ##M## is the nuclear mass, and ##E_\infty \approx 13.605693## eV
 
I think quantum mechanics brings in probabilities into physics ,so due to no determinism we cannot describe a general result for multielectron atoms.
 
That's not the reason we don't have a general result. The reason is that it's just too complicated for a simple analytical formula.
 

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