Understanding Excitation Energy in Atoms: Threshold Values and Potential States

  • Context: High School 
  • Thread starter Thread starter Bennet
  • Start date Start date
  • Tags Tags
    Energy Excitation
Click For Summary

Discussion Overview

The discussion revolves around the concept of excitation energy in atoms, particularly focusing on the conditions required for electrons to transition between energy levels and the implications for ionization. Participants explore the differences between precise energy matching for excitation and the threshold energy requirement for ionization.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant states that electrons must have energy that exactly matches the quantized energy levels to be excited from the ground state.
  • The same participant questions whether ionization requires a specific energy level or if any energy above a threshold is sufficient.
  • Another participant agrees that energy levels of bound states are quantized, while unbound states are not, suggesting that the energy for ionization can be imprecise as long as it exceeds a threshold.
  • A further contribution clarifies that photon energy does not need to match the energy difference exactly for excitation; rather, the interaction with the electromagnetic field can couple different energy eigenfunctions, affecting the probabilities of transitions to various levels.

Areas of Agreement / Disagreement

Participants express some agreement regarding the nature of energy levels and ionization thresholds, but there remains uncertainty about the specifics of excitation processes and the role of photon energy in these transitions.

Contextual Notes

There are unresolved aspects regarding the precise mechanisms of excitation and ionization, including the dependence on definitions of bound and unbound states, and the probabilistic nature of energy transitions.

Who May Find This Useful

This discussion may be of interest to students and enthusiasts of quantum mechanics, atomic physics, and those exploring the principles of energy levels and transitions in atoms.

Bennet
My physics textbook says roughly that:

Within an atom; when electrons are raised from the ground state to the energy levels that comprise their various atomic spectra, the potential energy carried by either a photon or an electron (or other) must exactly match these quantitative energy levels to excite the electrons into a raised potential state.

And if the energy of the incident "entity" does not match these critical values then nothing happens at all?

Yet it seems to be the case that to cause Ionisation of the same atom, the specific level of energy can be completely imprecise as long as it meets the requirements of being above a threshold value

Is this the case or have I got the wrong end of the stick?

Many thanks for any help provided. If stupid please be kind as never been on a forum before. Thanks.

(Detailed insight beyond high school level would be greatly appreciated if applicable.)
 
Physics news on Phys.org
Bennet said:
Yet it seems to be the case that to cause Ionisation of the same atom, the specific level of energy can be completely imprecise as long as it meets the requirements of being above a threshold value
I moved your question to the quantum section where I think it will get attention from people who can help with the math. However, what you say here is essentially correct. The energy levels of bound states are quantized, but unbound states are not.
 
thanks
 
Bennet said:
an electron (or other) must exactly match these quantitative energy levels to excite the electrons into a raised potential state.
Photon energy doesn't have to be exactly equal to the energy difference with some excited state for something to happen inside an atom. In general, interaction between atom and EM field causes a disturbance in which different energy eigenfunctions are coupled. It's just that the probability for the atom to end up in a level whose energy difference is closest to the photon energy is higher than those to end up in any other levels.
 
Last edited:

Similar threads

Undergrad Continuous Spectrum and Energy levels of Electrons (Energy Bands)
  • · Replies 7 ·
Replies
7
Views
3K
High School What happens to excess energy when an electron gets excited by light?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Why does the energy level of an electron in an atom have a width?
  • · Replies 3 ·
Replies
3
Views
2K
High School Are electrons in atoms always in eigenstates?
  • · Replies 6 ·
Replies
6
Views
2K
High School Energy needed for electron's change in energy level in an atom
  • · Replies 15 ·
Replies
15
Views
3K
Undergrad Is the potential energy always negative in the ground state of a hydrogen atom?
  • · Replies 12 ·
Replies
12
Views
2K
High School Interaction of light with atoms
  • · Replies 9 ·
Replies
9
Views
2K
High School Photoelectric effect and atomic excitation
  • · Replies 3 ·
Replies
3
Views
3K
High School How do electrons behave when energy is added to an atom's ground state?
  • · Replies 2 ·
Replies
2
Views
2K
High School A few basic questions about the absorption/emission of photons
  • · Replies 4 ·
Replies
4
Views
2K