Metastable solid He and the possible role of point defects.

The metastable phase of solid He and the possible role of point defects in its destabilization are investigated by the introduction of a trial function of the shadow class with an explicit symmetrical kernel. This is a trial function that ensures the possible exchange of atoms and the delocalization of atoms and defects in a very effective manner. We show that the formation energy for vacancies is equal to zero at a pressure P = 20 ± 2 atm, which is in excellent agreement with the experimental observation. The pressure at which a self-interstitial also has a formation energy equal to zero, is in agreement with the density where vacancies have the same property. Formation energies of a He interstitial or a substitutional impurity were estimated. Other properties of interest for systems made from He atoms are estimated and compared with results from the literature whenever available.