Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides.

ABSTRACT: Through a series of high pressure diamond anvil experiments, we report the synthesis of alkaline earth (Ca, Sr, Ba) tetrahydrides, and investigate their properties through Raman spectroscopy, X-ray diffraction, and density functional theory calculations. The tetrahydrides incorporate both atomic and quasi-molecular hydrogen, and we find that the frequency of the intramolecular stretching mode of the H2δ- units downshifts from Ca to Sr and to Ba upon compression. The experimental results indicate that the larger the host cation, the longer the H2δ- bond. Analysis of the electron localization function (ELF) demonstrates that the lengthening of the H-H bond is caused by the charge transfer from the metal to H2δ- and by the steric effect of the metal host on the H-H bond. This effect is most p

SUBMITTER: Pena-Alvarez M 

PROVIDER: S-EPMC9488899 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature