LiveJournal Brains: Liquid VS Gaseous Hydrogen...

[seawasp]

Anyone out there have pointers to a good reference on the physical parameters of the two states, assuming near-same temperatures and pressures (as you'd find in a tank that had some liquid H2 in it with gaseous H2 above)? I'm interested in physical, electromagnetic, etc., parameters and any differences. Some I can find easily (density, for instance), others not quite so much. I know METALLIC hydrogen has some drastically different properties but I don't know if that's the case for liquid VS gas.

Comments

[qinshihuangdi.livejournal.com]

Have you tried looking at the MSDS sheets for the liquid and the gas? The first thing that came to mind was to look in the back of my thermodynamics text for the gas tables. However, most of the stuff in the one closest to hand seems either too basic and brief or too esotaric. I don't know what kind of gas/vapour/liquid tables the CRC handbook has.

[kengr]

Well, off the top of my head, from an *old* article in Analog on the fun NASA had learning to handle liquid hydrogen (The Bugs That Live at -417° (I may have the temp wrong) was a cover article back in the 1960s some time) a big consideration is the ratio of ortho to para hydrogen molecules in the liquid.

As I recall one has the spins align in the same direction, the other has them in the opposite directions. The energy from transitioning from the higher to lower energy state is enough to boil the LH2 if there's a significant amount of the higher energy form present.

Apparently they have to run the LH2 thru a catalyst bed to force the transition while they are liquefying it.

ps. last I heard we haven't been able to confirm anything about metallic hydrogen. It *may* have been created in some high pressure setups, but wasn't stable in them.

[qhudspeth.livejournal.com]

I'd recommend talking to any of the principle investigators at the University of Florida's Microkelvin lab (http://www.phys.ufl.edu/~mkelvin/2/ContactIndex.html). They are very knowledgeable and agreeable people, any of which could point you to the right sources or possibly tell you what you need to know off the top of their heads. Try Mark Meisel or Yasu Takano first, I think.

Q