The changes in the electronic structure of B2FeAl alloy with a Fe antisite and absorbed hydrogen

E.A.GONZALEZ,P.V.JASEN, R.LUNA, P.BECHTHOLD, A.JUAN, G.BRIZUELA

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 404 p. 4216 - 4220

0921-4526

The electronic structure and bonding in a B2 FeAl alloy with and without hydrogen interaction with an Fe antisite were computed using a density functional theoretical method.The hydrogen absorption turns out to be a favorable process.The hydrogen was found close to an octahedral site where one of its Al capped is replaced by an Fe antisite.The Fe-H distance is of 1.45 Å same as the Al-H distance.The density of states (DOS) curves show several peaks below the d metal band which is made up mostly of hydrogen based states (>50% H1s) while the metal contribution in this region includes mainly s and p orbitals. An electron transfer of nearby 0.21e- comes from the metal to the H.The overlap population values reveal metal-metal bond breaking, the intermetallic bond being the most affected.The H bond mainly with the Al atom and the reported Fe-H overlap population is much lower than that corresponding to FePd alloys and BCC Fe.The changes in the overlap population show the Fe-Al bond is weakened nearly 41.5% after H absorption, while the Fe-Fe bond is only weakened 34.5%.H also develops a stronger bond with the Al atoms.The main bond is developed with Al being twice stronger than Fe-H.