Center for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Box 1033 Blindern N-0315, Oslo, Norway.
J Phys Chem A. 2011 Oct 6;115(39):10708-19. doi: 10.1021/jp2011342. Epub 2011 Sep 15.
The electronic structure, lattice dynamics, and mechanical properties of AlH(3) phases have been studied by density functional calculations. The chemical bonding in different polymorphs of AlH(3) are evaluated on the basis of electronic structures, charge density analysis, and atomic charges, as well as bond overlap population analysis and the Born effective charges. The phonon dispersion relations and phonon density of states of all the polymorphs of AlH(3) are calculated by direct force-constant method. Application of pressure induces seqauence of phase transitions in β-AlH(3) which are understood from the phonon dispersive curves of the involved phases. The previously predicted phases (Chem. Mater. 2008, 20, 5997) are found to be dynamically stable. The calculated single crystal elastic constants reveal that all the studied AlH(3) polymorphs are easily compressible. The chemical bonding of these polymorphs have noticeable covalent character (except the hp2 phase) according to the present chemical bonding analyses. For all these polymorphs, the NMR-related parameters, such as isotropic chemical shielding, quadrupolar coupling constant, and quadrupolar asymmetry, are also calculated. All IR- and Raman-active phonon frequencies, as well as the corresponding intensities, are calculated for all the AlH(3) polymorphs and are compared with available experimental results.
通过密度泛函计算研究了 AlH(3)相的电子结构、晶格动力学和力学性能。基于电子结构、电荷密度分析和原子电荷，以及键重叠人口分析和玻恩有效电荷，评估了 AlH(3)不同多晶型体的化学结合。通过直接力常数法计算了所有 AlH(3)多晶型体的声子色散关系和声子态密度。压力的应用导致了β-AlH(3)中的一系列相变，这些相变可以从涉及的相的声子弥散曲线中理解。先前预测的相（Chem. Mater. 2008, 20, 5997）被发现是动态稳定的。计算得到的单晶弹性常数表明，所有研究的 AlH(3)多晶型体都很容易压缩。根据目前的化学键分析，这些多晶型体的化学键具有显著的共价性质（除了 hp2 相）。对于所有这些多晶型体，还计算了与 NMR 相关的参数，如各向同性化学屏蔽、四极偶合常数和四极不对称性。计算了所有 AlH(3)多晶型体的所有 IR 和 Raman 活性声子频率及其相应的强度，并与现有实验结果进行了比较。
