# Solid diprotium saturated vapour density

• I
• snorkack
In summary: Um. Ices are already dust.Hydrogen and helium are as yet gases, even in molecular clouds.Molecular clouds are made up of gas and dust.Do you expect that the pressure would be subject to some sort of Antoine equation?Here's another (table 6) with eqn ##A + B/T + B'\ln T##Page 17. For eH2, it gives A as 2,5 (for Torr), B as -85,3, B' as 2,9.For 2,7 K, that would mean B/T=-31,6, ln T=1, B´/ln T=2,9
snorkack
What precisely is the equilibrium vapour density of bulk solid diprotium surface now, at 2,7 K?

The density of the world falls with some power of temperature (which one?). The density of saturated vapour falls exponentially.
At which temperature shall the world saturate with respect to bulk solid diprotium?

What has your research brought you so far ? Any reason you don't like hydrogen and focus on the isotope that's overwhelmingly dominant anyway ?
http://www.tvu.com/PEngPropsSH2Web.htm
https://www1.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm01r0.pdf
https://en.wikipedia.org/wiki/Solid_hydrogen
https://nvlpubs.nist.gov/nistpubs/jres/47/jresv47n2p63_a1b.pdf

Can you give some more context ? What are you trying to find ? What, for example is the reason you want it 'precisely' (without giving a definition) ? In an age of global warming it might be good enough to use approximate values from physical property approximation expressions and equations of state ?

Anyway, why look at solid hydrogen when first the oceans freeze, then O2 and N2 condense etc etc ?
snorkack said:
The density of the world falls with some power of temperature (which one?)
The temperature of the earth, of course
But if the 'which' refers to the power, then I'd start with 1 (see iron/nickel or rock)

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berkeman
BvU said:
What has your research brought you so far ?
Tables tend to break off at temperatures far above 2,7 K.
BvU said:
That one was useful.
Vapor pressure of the solid (20.4 K equilibrium hydrogen) follows the equation

log P (mm Hg) = A + B/T + CT,

where A = 4.62, B = -47.02, C = 0.02023, although the vapor pressures for a mixtures closer to normal hydrogen are somewhat lower [3]
For 2,7 K, I get log P at about -13.
BvU said:
Can you give some more context ? What are you trying to find ? What, for example is the reason you want it 'precisely' (without giving a definition) ? In an age of global warming it might be good enough to use approximate values from physical property approximation expressions and equations of state ?

Anyway, why look at solid hydrogen when first the oceans freeze, then O2 and N2 condense etc etc ?
The temperature of the earth, of course
But if the 'which' refers to the power, then I'd start with 1 (see iron/nickel or rock)
Hydrogen and helium are as yet gases, even in molecular clouds.
How does that present equilibrium vapour pressure, of 10-13 mm Hg, compare with pressure in molecular clouds?

Dunno, but outer space is different from 'the world' . With a few H atoms per m3 there's no chance of solid formation.

snorkack said:
For 2,7 K, I get log P at about -13
wouldn't trust those numbers: with those values in the Antoine eqn I can't even reproduce the pressures they mention ! and 2.7 K is extrapolating way out...

snorkack said:
compare with pressure in molecular clouds
Those guys have funny 'standard units' P/kB of 104 to 107 cm-3 K, it seems (nice exercise: convert to mm Hg -- I get 10-15 to 10-12 , so perhaps a case of oops! -- but I may well be mistaken. It's past bedtime here )

But then again, when you google 'interstellar ice' or 'volatiles' ...

Let me know if and how you find inroads for this diprotonium ice !

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BvU said:
wouldn't trust those numbers: with those values in the Antoine eqn I can't even reproduce the pressures they mention ! and 22.7 K is extrapolating way out...
Sure, but I could not find actual measurements for 2,7 K.
Do you expect that the pressure would be subject to some sort of Antoine equation?

Here's another (table 6) with eqn ##A + B/T + B'\ln T##
Perhaps you can sort out he references mentioned here (section 2.2.30) ; data are on P 6-288

BvU said:
Here's another (table 6) with eqn ##A + B/T + B'\ln T##
Page 17. For eH2, it gives A as 2,5 (for Torr), B as -85,3, B' as 2,9.
For 2,7 K, that would mean B/T=-31,6, ln T=1, B´/ln T=2,9
then ln Q=2,5-31,6+2,9=5,4-31,6=-26,2
log Q=ln Q/2,303=-11,5

Thus, two sources give P as 10-13 and 10-11,5 mm Hg respectively. Appreciable divergence, but not unreasonably big seeing how these are extrapolated out of the measurable range. Same ballpark.
How do these numbers - 10-13...10-11 mm Hg - compare to the present pressures in molecular clouds?

## 1. What is solid diprotium saturated vapour density?

Solid diprotium saturated vapour density is the measure of the maximum amount of diprotium (H2) gas that can be present in a given volume of space at a specific temperature and pressure, when the solid form of diprotium is in equilibrium with its gaseous form.

## 2. How is solid diprotium saturated vapour density measured?

The density of solid diprotium saturated vapour is typically measured using a gas chromatography technique, where a sample of gas is passed through a column and separated based on its different components, including diprotium. The amount of diprotium present in the sample can then be quantified through detectors and calculations.

## 3. What factors can affect the density of solid diprotium saturated vapour?

The density of solid diprotium saturated vapour can be affected by factors such as temperature, pressure, and the presence of impurities. Higher temperatures and pressures can increase the density, while impurities can lower it.

## 4. Why is the study of solid diprotium saturated vapour density important?

Understanding the density of solid diprotium saturated vapour is crucial in various fields, such as chemical engineering, environmental science, and astrophysics. It can provide insights into the behavior of diprotium gas at different conditions and help in the development of new technologies and processes.

## 5. Can the density of solid diprotium saturated vapour change?

Yes, the density of solid diprotium saturated vapour can change depending on the surrounding conditions. For example, changes in temperature or pressure can cause the gas to condense or evaporate, leading to a change in density. Additionally, the presence of impurities can also alter the density of the gas.

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