Why the statistics for a real gas are not quantum in nature?

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SUMMARY

The discussion centers on the behavior of diatomic gases, specifically H2, and their adherence to classical statistical distributions at room temperature. It is established that at this temperature, the vibrational modes of diatomic gases become irrelevant, leaving only translational and rotational degrees of freedom, which conform to classical statistics. This phenomenon is also applicable to monatomic gases like helium (He). Textbooks on statistical physics provide further insights into the classical limit of gas behavior.

PREREQUISITES
  • Understanding of quantum statistics for bosons and fermions
  • Familiarity with classical statistical mechanics
  • Knowledge of degrees of freedom in molecular gases
  • Basic principles of thermodynamics and temperature effects
NEXT STEPS
  • Study the classical limit in statistical mechanics
  • Explore the role of translational and rotational degrees of freedom in gases
  • Learn about the vibrational modes of diatomic gases and their significance
  • Investigate the differences between quantum and classical statistics in various gas types
USEFUL FOR

Students of physics, researchers in statistical mechanics, and anyone interested in the behavior of gases under varying temperature conditions will benefit from this discussion.

MichPod
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TL;DR
If the gas molecules are either bosons or fermions, why the gas statistics is classical?
A gas of bosons or fermion particles follows a particular quantum statistics. Then why a molecular gas (say, H2) follows a classical distribution statistics? Is it not the case that the molecules should be indistinguishable one from another and be either bosons or fermions? What is exactly the condition which allows a classical statistics?
 
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MichPod said:
why a molecular gas (say, H2) follows a classical distribution statistics?

What makes you think it does?
 
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PeterDonis said:
What makes you think it does?

Lack of education, I guess. :-)
Case resolved, thank you for the hint.
 
True, and quantum mechanics tells you, which degrees of freedom are relevant at a given temperature. E.g., at room temperature the vibrational modes of a diatomic gas are irrelevant and only the translational and rotational ones play a role.
 
DrClaude said:
At room temperature, diatomic gases behave classically.

So do monatomic gases like He.
 
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