第一性原理计算Mg2Ni氢化物的电子结构及其稳定性分析

对Mg₂Ni及其氢化物的能量和电子结构进行了第一性原理计算,并对Mg₂Ni低温氢化物和高温氢化物的稳定性进行了分析.结果发现:在Mg₂Ni中,Mg与Ni存在较强的相互作用.H原子的加入使得Mg的价电子向Ni的3d轨道转移,并在Ni-3d轨道和Ni-4p轨道间形成了带隙.Ni-4s和H-1s电子之间的成键作用,使得Mg和Ni间相互作用减弱了;从LT-Mg₂NiH₄中去掉一个H原子比HT-Mg关键词：第一性原理2Ni')" href="#">Mg₂Ni2NiH₄')" href="#">Mg₂NiH₄结构稳定性

First principles investigation of electronic structuresand stabilities of Mg2Ni and its complex hydrides

First-principle calculations are carried out to investigate the energies and the electronic structures of Mg₂Ni alloy and its high/low temperature hydrides. Results show that strong bonding interaction between Mg and Ni atoms exists in the Mg₂Ni alloy. With H inserted, the charge transfer occurs from Mg to Ni-3d, which gives rise to a band gap between Ni-3d and Ni-4p orbitals. The interaction between Mg and Ni in LT/HT-Mg₂NiH₄ hydrides is weakened due to the covalent bonding between Ni-4s and H-1s. Therefore, it neads more energy to remove H atoms from LT-Mg₂NiH₄ than from HT-Mg₂NiH₄, indicating that HT-Mg₂NiH₄ is more suitable for de-hydrogenation reaction while the LT-Mg₂NiH₄ is suitable for hydrogenation reaction.