A study on the correlation between electronic structures of RENi5 and their hydrides and hydrogen absorption properties

The electronic structures of RENi5 (RE = La, Ce, Pr, Nd) and their hydrides were investigated by the SCC-DV-X alpha (Self-Consistent-Charge Discrete V ariational X alpha) method. The results show that the stabilities of RENi5 hydrides are related to the charge transferred to the hydrogen atom, and de crease with increase of the transferred charge. There is a strong orbital i nteraction between the 3d orbit in the Ni atom and the 4f orbit in the RE a tom, which is weakened when the hydride is formed. The equilibrium plateau pressure of RENi5 rises with lowering of the Fermi energy of the hydride. ( C) 2001 Elsevier Science Ltd. All rights reserved.