Stabilization of solid phases with unusual combinations or stoichiometries, and unexpected electronic structures may be achieved by applying external pressure. The prediction of these structures using our chemical intuition (developed at 1 atmosphere) would be exceedingly difficult, making automated structure search techniques prudent. For this reason, we have written XtalOpt, an open-source evolutionary algorithm for crystal structure prediction.Whereas at 1 atmosphere the classic alkali hydrides combine in a one-to-one ratio, M+H-, under pressure non-classic stoichiometries MHn(n > 1) and MmH (m > 1) are preferred. These hydrogen-rich materials with nontraditional stoichiometries, like LiH6, NaH9 and CsH3, are computed to undergo an insulator to metal transition at pressures attainable in diamond anvil cells. It may be that they are superconductors at experimentally achievable pressures.

Building a chemical intuition under pressure: Prediction of polyhydride and subhydride phases

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.