Experiments · E253
Pre-registration
The pre-registration, as written
E253 — Free energy at temperature, and whether bcc is even stable (J9.)
- MACE phonons (finite displacement 0.01 Å) on a 54-atom random cell of each candidate and on its three closest competitors. Harmonic F_vib(T) at 90 to 1000 K; G = E + F_vib − T·S_config.
- The same phonons show whether the bcc cell is dynamically stable (imaginary modes), which matters for Ti-, Zr- and Hf-rich alloys.
- Prediction: vibrational terms move rung-2 margins by under 20 meV/atom, but some Ti/Zr/Hf-rich cells show imaginary modes. ~half a day of cores.
Results
No result paragraph for this entry was found in the log — it is pre-registered and has not reported.
The full record
This entry is written in 2 separate places in the log, shown here in log order.
EXPERIMENTS.md · lines 17327–17333
E248–E255 — the review's experiments: one per open question, parameters fixed (registered 2026-09-27 22:50)
The external review (Jan, 2026-09-26) asked questions that could show the ladder is wrong. The ones not already answered become these eight experiments, run one at a time in this order. Each gets its own entry, with bars, before it runs; the parameters and predictions below are fixed now. Already settled: R0 is a ranking (J1–J2); the Mo–Ta reference is corrected (J5); the requirement is one disordered phase (J14, E247).
EXPERIMENTS.md · lines 17386–17392
E253 — Free energy at temperature, and whether bcc is even stable (J9.)
- MACE phonons (finite displacement 0.01 Å) on a 54-atom random cell of each candidate and on its three closest competitors. Harmonic F_vib(T) at 90 to 1000 K; G = E + F_vib − T·S_config.
- The same phonons show whether the bcc cell is dynamically stable (imaginary modes), which matters for Ti-, Zr- and Hf-rich alloys.
- Prediction: vibrational terms move rung-2 margins by under 20 meV/atom, but some Ti/Zr/Hf-rich cells show imaginary modes. ~half a day of cores.
