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The carbon bonds in a benzene molecule oscillate between single and double bonds. As they do so, the distances between the carbon atoms changes (as the attached animated GIF illustrates). Benzene oscillation

At absolute zero all molecular motion ceases; that is, the molecules stop bouncing into each other, but does that mean that molecules like benzene also cease their internal molecular motion?

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marked as duplicate by Mithoron, Tyberius, Jon Custer, aventurin, A.K. Jun 21 '18 at 15:48

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"At absolute zero all molecular motion ceases; that is, the molecules stop bouncing into each other"

This statement is a common misconception about absolute zero and is totally false. At absolute zero, we are simply in the lowest possible energy state. That does not mean that molecular motion ceases. That would violate the uncertainty principle.

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    $\begingroup$ To be more specific, molecules still have zero-point (vibrational) energy at absolute zero. One should not confuse molecular (nuclear) motion with electronic motion, which is even less well-defined due to electron positions being probability distributions. $\endgroup$ – pentavalentcarbon Jun 19 '18 at 22:56
  • $\begingroup$ When I said, "...all molecular motion ceases," I tried to qualify that by adding, "...molecules stop bouncing into each other." If the last statement is false, some clarification would be appreciated. If there is a term for motion within an atom and motion as one atom relates to a neighboring atom, I am not aware of it or have forgotten it. $\endgroup$ – BillDOe Jun 19 '18 at 23:24
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    $\begingroup$ @BillDOe He (at 1atm) is not even a solid in the limit of absolute zero. physics.stackexchange.com/questions/274910/… It remains liquid, so the atoms are certainly bouncing into each other. $\endgroup$ – BowlOfRed Jun 20 '18 at 3:13
  • $\begingroup$ Thanks. I'm obviously a victim of that common misconception. $\endgroup$ – BillDOe Jun 20 '18 at 18:04

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