How Do Quantum Theory and Software Model Large Atoms Like Iron?

  • Context: Graduate 
  • Thread starter Thread starter VVS
  • Start date Start date
  • Tags Tags
    Atoms Model
Click For Summary

Discussion Overview

The discussion revolves around the application of quantum theory to model larger atoms, specifically iron, and how to predict their behavior in various environments. Participants explore the intersection of quantum mechanics and statistical mechanics, as well as the computational tools available for such modeling.

Discussion Character

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

Main Points Raised

  • One participant suggests that modeling larger atoms like iron may involve statistical mechanics, although their current understanding is limited to heat.
  • Another participant explains that while the initial approach can be a two-body problem, interactions between electrons must be considered, and the results of quantum mechanics can be used in statistical mechanics to describe macroscopic properties.
  • A participant expresses interest in evaluating the effects of electric and magnetic fields on iron in hemoglobin, seeking guidance on how to approach this analysis.
  • It is proposed that protein folding software may be necessary to account for the influence of fields on the entire molecular structure rather than just individual atoms.
  • One participant comments on the treatment of the hydrogen atom as a one-body problem, noting the need for a wave function to describe the nucleus in real physics.
  • Another participant clarifies that the two-body problem can be simplified to a one-body problem using reduced mass, incorporating both electron and nucleus dynamics.
  • A later reply highlights the use of quantum chemistry software to handle real atoms and molecules, mentioning specific methods like Hartree-Fock and coupled cluster methods for modeling electron behavior in response to external fields.

Areas of Agreement / Disagreement

Participants present multiple competing views on the modeling of larger atoms and the necessary computational approaches, indicating that the discussion remains unresolved with no consensus reached.

Contextual Notes

There are limitations in the discussion regarding assumptions about the simplifications used in modeling, the complexity of quantum chemistry methods, and the specific applications of these methods to different scenarios.

VVS
Messages
85
Reaction score
0
Hi!

One can easily analyze the Hydrogen Atom since it is a two body problem.
But how do you apply Quantum Theory to model atoms (such as iron) which are much larger and predict their behaviour in an environment?
My guess is that you use statistical mechanics, but I only just started a course and it is basically limited to heat.

thank you
VVS
 
Physics news on Phys.org
The first approach is still a two-body problem. Afterwards, interactions between the electrons can be taken into account. To describe the state of the electrons and bonds in a material, this is pure quantum mechanics.
If you want to describe things like heat, you don't have to care about those details, you take the "output" of quantum mechanics (crystal structure, energy bands and so on) and apply statistical mechanics to it.
 
Hi mfb!
Thanks for your answer.
Basically I want to evaluate the effect of electric fields, magnetic fields and magnetic vector potentials on the properties of Iron in haemoglobin.
How do I go about this?
 
I guess that will need some protein folding software if you expect effects - the fields influence the whole thing, not just a single small atom inside.
 
By the way, I think we analyze the Hydrogen atom by quantum mechanics is a one body problem, because we assume the nuclear is fixed, and it just provide a potential to the atom system, but in the real physics we should also use a wave-function to describe the nuclear
 
Usually the two-body problem is reduced to a 1-body problem with a reduced mass, so both electron and nucleus are taken into account. The other degrees of freedom of the two-body system correspond to a total motion of the atom.
 
OP, real atoms (and molecules) are handled with quantum chemistry software. Such programs (e.g., Molpro, Orca) can solve the many-body Schrödinger equations in various approximations to determine the quantitative behavior of the electrons, including their response to external fields. For Iron atoms, for example, you would employ approximations like Hartree-Fock and CCSD(T) (a coupled cluster method) or Multi-configuration self consistent field (MCSCF) and mutli-reference configuration interaction (MRCI), depending on the application.

Understanding and using such approximations (correctly) is not easy, and normally requires some background reading in many-body quantum mechanics and quantum chemistry.
 

Similar threads

  • · Replies 20 ·
Replies
20
Views
17K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 91 ·
4
Replies
91
Views
9K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 11 ·
Replies
11
Views
5K