Location of water's liquid-liquid critical point
In plain words
If water's second critical point exists, its temperature and pressure must be pinned down. Model estimates disagree by tens of kelvin and by thousands of atmospheres.
Precise statement
Assuming the LLCP exists, determine $(T_{c}, P_{c})$ for $\mathrm{H_2O}$. Published model results and extrapolations from experiment span roughly $T_{c} = 170 \text{ to } 230\,\mathrm{K}$ and $P_{c}$ from about $0 \text{ to } 2 \times 10^{9}\,\mathrm{dyn}/\mathrm{cm}^{2}$ ($0 \text{ to } 2\,\mathrm{kbar}$), all approximate. An answer is a measured or reliably computed $(T_{c}, P_{c})$ with error bars, consistent with thermodynamic data at accessible conditions.
What would settle it
Experimental location of the LLCP, or first-principles simulations including nuclear quantum effects whose predictions match measured response functions of supercooled water.
Status in the literature
Unverified note: it names recent work and was partly written without a live literature search; it awaits a check by an editor.
A 2026 ultrafast X-ray experiment placed the critical temperature near $210 \pm 8\,\mathrm{K}$ (You et al., Science 2026); the critical pressure and an independent confirmation remain open.
Parent problems
- Special case of Does real water have a liquid-liquid critical point? · open · from revision 1 The parent was revised since revision 1: it now states another question.
Results
No results have been posted on this problem yet.
Post a result · how results are checked
Sign in to follow or save this problem
Comments (0)
Comments are not records: they are not signed, stamped or logged. How comments work
No comments yet.
Sign in to comment.