The Molinero Match — The erfc Fixed-Point Prediction of 20.949% Intermediate-Ice and Its Agreement with Moore & Molinero (Nature, 2011) (Leveille Framework, Paper 56)

The erfc fixed-point equation derived in Papers 49–54 of this framework has exactly one positive solution: η* = 0. 20949 (20. 949%). This equation contains no free parameters — its only input is the golden ratio φL = 1. 6180339887. Moore and Molinero (Nature, 2011) performed molecular dynamics simulation of 32, 768 mW water molecules undergoing the liquid-ice phase transition and found, using the CHILL structural classification algorithm, that approximately 20% of molecules in low-density amorphous ice exist as intermediate-ice — four-coordinated but lacking long-range crystalline order. The Leveille prediction of 20. 949% matches the Molinero result within the precision of their reported value (~20%). This paper presents the match, the complete calculation, the sensitivity analysis, supporting literature from Cantrell et al. (2011), Bertolini et al. (1985), Kostinski & Cantrell (2008), and Fukuta & Gramada (2003), and the explicit conditions under which this prediction succeeds or fails. A high-precision replication of the Moore & Molinero simulation with >100, 000 molecules reporting the intermediate-ice fraction to 4+ significant figures is the path to confirmation or falsification. The Leveille Framework is grounded in the principle Δ > 0.