[augustine]

This isn't a part of my Chemistry course, but I wasn't sure what category it would fit into otherwise.

I'm currently reading a book on basic interstellar chemistry, and at one point it mentions parallel and antiparallel Hydrogen. The author doesn't state it explicitly but it seems that the antiparallel state is simply 1s1, and parallel 1s2. What confused me was that he mentions 'magnets' in reference to quantum mechanics in order to explain this use of terminology. He says that the magnet can only line up pointing in the same (parallel) or opposite (antiparallel) directions. Maybe I'm just taking it too literally but I can't figure out what this means, as there is only one electron and one proton.

I realise the confusion is coming from a lack of adequate knowledge in chemistry and quantum mechanics, but it's been really bugging me and I can't find any answers on the Internets to explain it. Could some one give us a hand?

[Borek]

Could be author uses magnets to describe spins.

1s2 is helium, not hydrogen.

Are you sure it is not about ortho/para hydrogen molecules?

[augustine]

Hi Borek, sorry for the late reply- I'd expected to get an email notifying me of responses.

I've read about spins a little bit, but the concept is still pretty difficult to me so it's possible that he's talking about it without me realising. The book is aimed at total novices so there's not really any detail where it's not needed, especially with tough quantum-physics-y stuff. I suppose I'll have to wait a while yet to understand it.

I used the 1s2 notation to describe the position of the single electron in its shell. Is this not right? The author said that there is a very small difference in energy levels when an electron goes from it's groundstate to the next highest position within the shell, so I just assumed that it somehow corresponded to the 1s1/1s2 levels- and incorrectly it would seem.

After a brief googling, it seems that you're right with the ortho/para hydrogen suggestion. Thanks! I still don't really understand it, what with not understanding spin, but I'll do some more reading and try to get a good grip on it.

Thankyou