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?