Violation of the minimum h-h separation "Rule" for metal hydrides

P Ravindran; P Vajeeston; R Vidya; A Kjekshus; H Fjellvåg

doi:10.1103/PhysRevLett.89.106403

Violation of the minimum h-h separation "Rule" for metal hydrides

Phys Rev Lett. 2002 Sep 2;89(10):106403. doi: 10.1103/PhysRevLett.89.106403. Epub 2002 Aug 20.

Authors

P Ravindran¹, P Vajeeston, R Vidya, A Kjekshus, H Fjellvåg

Affiliation

¹ Department of Chemistry, University of Oslo, Box 1033, Blindern, Norway. ponniah.ravindran@kjemi.uio.no

PMID: 12225210
DOI: 10.1103/PhysRevLett.89.106403

Abstract

Using gradient-corrected, full-potential, density-functional calculations, including structural relaxations, it is found that the metal hydrides RTInH1.333 (R=La, Ce, Pr, or Nd; T= Ni, Pd, or Pt) possess unusually short H-H separations. The most extreme value (1.454 A) ever obtained for metal hydrides occurs for LaPtInH1.333. This finding violates the empirical rule for metal hydrides, which states that the minimum H-H separation is 2 A. The paired, localized, and bosonic nature of the electron distribution at the H site are polarized towards La and In which reduces the repulsive interaction between negatively charged H atoms. Also, R-R interactions contribute to shielding of the repulsive interactions between the H atoms.