Can the atomic liquid Hydrogen exist?

In summary, when atomic Hydrogen is under standard temperature and pressure, the electrons have the same spin and recombination cannot occur. However, if the vessel is cooled below 20.28 K, the question of whether the Hydrogen will liquefy, remain in a gaseous state, or turn into molecular Hydrogen arises. It is possible to achieve the same spin for 2 electrons in 1 orbital, but this is not possible for Hydrogen. There have been attempts to generate liquid atomic Hydrogen, but the lifetime of orthohelium, which is a possible excited state, is only 8000 seconds. Spin aligned Hydrogen cannot be described by a single lifetime because the speed of spin reorientation depends on temperature and density
  • #1
Eagle9
238
10
Imagine that we have got some vessel under standard temperature and pressure filled with atomic Hydrogen inside and the electrons of these atoms have got the same spin and therefore they cannot join into Hydrogen molecules, so the process of recombination does not occur. Then we begin cooling the vessel lower 20.28 K (boiling point for molecular Hydrogen) temperature. The question is-what will happen? Will the atomic Hydrogen liquefy or will it remain in gaseous condition? Or maybe it will be turned into molecular Hydrogen?
 
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  • #2
How do those electrons have the same spin? Its more like "if there are 2 electrons in 1 orbital, they WILL have antiparallel spins". What you said is just not possible.
 
  • #3
chill_factor
How do those electrons have the same spin?
I do not know if it possible to achieve this from the technical point of view, but just imagine that it is done. I would like to know:
The question is-what will happen? Will the atomic Hydrogen liquefy or will it remain in gaseous condition? Or maybe it will be turned into molecular Hydrogen?

Its more like "if there are 2 electrons in 1 orbital, they WILL have antiparallel spins".
Well, this can happen in case of heavier elements, but not Hydrogen.
 
  • #5
chill_factor said:
How do those electrons have the same spin? Its more like "if there are 2 electrons in 1 orbital, they WILL have antiparallel spins". What you said is just not possible.

No, the reasoning is "if 2 electrons have parallel spins, they CANNOT go to the same orbital".

Example in case - ortohelium.

Both electrons have the same spin.
THEREFORE they CANNOT share an orbital, such as the lowest, 1s one. If one electron winds up in 1s orbital, the lowest available one for the other is 2s orbital.

This is an excited state - about 20 eV above the ground state where the electrons have opposite spins and both fit in 1s.

It is possible to change the spin of an electron so as to go to 1s ground state. This, however, is extremely hard.

The lifetime of orthohelium is quoted in the region of 8000 seconds - which is 2 hours. Does someone know what the decay process actually is?

Now suppose you could somehow produce atomic hydrogen gas with aligned spins.

Unless two hydrogen atoms can somehow change one electron spin to fit the electrons into a common orbital, they cannot form a bond - they repel and scatter off each other. And when they are not interacting, they have no reason to change spin. Thus spin aligned hydrogen cannot be described by single lifetime like orthohelium, because the specific speed of the process of spin reorientation events would depend on the specific frequency of interactions - temperature and density. In any case, it could be expected that the spin reorientation would be slow.

If spin aligned hydrogen could be produced in large quantities, could it be cooled, in face of the infrequent spin flip caused recombinations releasing heat, to the extent that the atoms would under van der Waals forces condense into liquid or solid?
 
  • #7
DrDu
Nasa has a patent on it:
https://docs.google.com/viewer?a=v&q...ehktCm6_rAXOkg [Broken]
Thanks! Very interesting! :shy:
I also remember about an article on experiments to generate liquid atomic hydrogen in Scientific American, maybe in the 1980's.
And did they succeed in it?

snorkack
This is an excited state - about 20 eV above the ground state where the electrons have opposite spins and both fit in 1s.
And how this Helium is excited? By means of lasers? Magnetic field? Other methods?
The lifetime of orthohelium is quoted in the region of 8000 seconds - which is 2 hours. Does someone know what the decay process actually is?

Now suppose you could somehow produce atomic hydrogen gas with aligned spins.

Unless two hydrogen atoms can somehow change one electron spin to fit the electrons into a common orbital, they cannot form a bond - they repel and scatter off each other. And when they are not interacting, they have no reason to change spin. Thus spin aligned hydrogen cannot be described by single lifetime like orthohelium, because the specific speed of the process of spin reorientation events would depend on the specific frequency of interactions - temperature and density. In any case, it could be expected that the spin reorientation would be slow.
Well…….can you tell me how to calculate the necessary time for recombination? I opened the topic here https://www.physicsforums.com/showthread.php?t=624890 but nobody answered.
If spin aligned hydrogen could be produced in large quantities, could it be cooled, in face of the infrequent spin flip caused recombinations releasing heat, to the extent that the atoms would under van der Waals forces condense into liquid or solid?
Well, the recombination will slowly occur, the heat will be emitted and dispersed, so probably hydrogen will be cooled :wink:
 
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  • #8
Eagle9 said:
And did they succeed in it?

No, if I remember well, the problem was that spin flip is to rapid. This whole subject became a turn with the generation of Bose Einstein Condensates in the nineties in magnetic traps. AFAIK, BECs of Hydrogen atoms have not been prepared, yet.
 
  • #9
DrDu said:
No, if I remember well, the problem was that spin flip is to rapid. This whole subject became a turn with the generation of Bose Einstein Condensates in the nineties in magnetic traps. AFAIK, BECs of Hydrogen atoms have not been prepared, yet.
But what about the NASA patent the link of which you posted here? I read it, they say that it is possible to store solid atomic Hydrogen (page 3, BACKGROUND OF THE INVENTION). Why it is so difficult to store liquid atomic Hydrogen and relatively easy-solid one? :uhh:
 
  • #10
Because the atoms are bound to the surface which creates an energetic barrier for recombination.
 
  • #12
Oh, that's interesting. Good you found it!
 
  • #13
Eagle9 said:
snorkack

And how this Helium is excited? By means of lasers? Magnetic field? Other methods?

Trivially easy. Just about anything that ionizes helium and allows it to recombine.

There is no guarantee that an electron which comes across a helium ion has opposite spin to the lone electron of the ion. Once the electron has recombined, even to a higher orbital than 2s, all decays changing electron spin are extremely unlikely, so orthohelium states will decay to the lowest available orthohelium state... which is long lived.
 
  • #14
DrDu
Because the atoms are bound to the surface which creates an energetic barrier for recombination
And why it is difficult/impossible to do the same with liquid atomic Hydrogen?

snorkack
Trivially easy. Just about anything that ionizes helium and allows it to recombine.

There is no guarantee that an electron which comes across a helium ion has opposite spin to the lone electron of the ion. Once the electron has recombined, even to a higher orbital than 2s, all decays changing electron spin are extremely unlikely, so orthohelium states will decay to the lowest available orthohelium state... which is long lived.
Ok, thanks :smile: and what can you say about this?
 
  • #15
The density and thus collision rate in a liquid (any liquid) is much higher than in the gas.

The life time of the metastable state will be strongly affected by that.
 

1. Can the atomic liquid Hydrogen exist?

Yes, it is possible for atomic liquid Hydrogen to exist under certain conditions. However, it is extremely difficult to create and maintain this state of matter, as Hydrogen tends to vaporize at low temperatures.

2. What are the conditions required for atomic liquid Hydrogen to exist?

The conditions required for atomic liquid Hydrogen to exist include extremely low temperatures (below -252.87°C or -423.17°F) and high pressures (over 1 million atmospheres). Additionally, it must be contained in a specially designed container to prevent it from vaporizing.

3. Why is it difficult to create and maintain atomic liquid Hydrogen?

Hydrogen is the lightest element and has a very low boiling point, making it difficult to keep in its liquid state. It also has a tendency to leak through container walls, making it challenging to contain at high pressures.

4. What are the potential applications of atomic liquid Hydrogen?

Atomic liquid Hydrogen has potential applications in fields such as rocket fuel, energy storage, and superconductivity studies. It could also provide insight into the behavior of other elements under extreme conditions.

5. Has atomic liquid Hydrogen been observed in nature?

There have been some claims of observing atomic liquid Hydrogen in the atmospheres of gas giant planets such as Jupiter and Saturn. However, these claims are still highly debated and have not been confirmed by scientific evidence.

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