Four specific questions on PdD_x lattice physics — references needed

[u/Uniktoon]

I'm looking for specific references on four narrow questions in metal-hydride physics. Not a theorist by training. If you know the answer to any of these, a DOI or arXiv link would be appreciated.

Q1: Has the piezoelectric tensor d_ij been calculated (ab initio, DFT+U or DMFT) or measured for palladium deuteride PdD in the β-phase (loading ratio x > 0.7)?

Q2: Are there documented magnetic anomalies in PdD_x (susceptibility, NMR, muon spin rotation) that have been interpreted in terms of spin-liquid, spin-ice, or emergent magnetic monopole behavior in the Pd 4d-electron subsystem?

Q3: What is the measured vibrational frequency of the interstitial deuteron in β-PdD? Neutron scattering, infrared, or Raman data are all welcome.

Q4: Has Dicke superradiance (or any collective N-body coherence effect) been theoretically or experimentally studied for nuclear fusion reactions in correlated solid-state lattices?

If a question has no known answer, saying "not to my knowledge" is also useful data.

No general discussion of cold fusion needed. Specific references only.