On the existence of MHn species with M=Al, Ga and n=4, 5, 6. Computational study of structures, stabilities and bonding |
| |
Authors: | Jerzy Moc Karolina Bober Jarosław Panek |
| |
Institution: | (1) Faculty of Chemistry, Wroclaw University, F. Joliot-Curie 14, 50-383 Wroclaw, Poland |
| |
Abstract: | Based on second-order perturbation theory (MP2) predictions with large 6-311++G(3df, 3pd) basis set we have reviewed the possible structures and stabilities of a series of neutral MHn(M=Al, Ga; n=4, 5, 6) species. For AlH4 and AlH5, our results confirm the previous theoretical findings, which indicate the dihydrogen Cs complexes (2A′) AlH2(H2) and (1A′) AlH3(H2), respectively, as the lowest energy isomers. We found, similarly, Cs (2A′) GaH2(H2) and (1A′) GaH3(H2) van der Waals complexes as the most stable species of the gallium analogues GaH4 and GaH5. The calculated H2 dissociation energies (De) for AlH2(H2) and AlH3(H2) are of the order 1.8–2.5 kcalmol1, whereas this range of values for GaH2(H2) and GaH3(H2) is 1.4–1.8 kcalmol1 . Symmetry-adapted perturbation theory (SAPT) was used to analyze the interaction energies of these dihydrogen complexes (for n=5) to determine why the Ga species show a smaller binding energy than the Al species. The SAPT partitioning of the interaction energy showed significant differences between AlH3(H2) and GaH3(H2), resulting from the much stronger “hydride” character of the aluminum species. The experimental observation of AlH2(H2) and AlH3(H2), and likely GaH3(H2), via low-temperature matrix isolation has been reported recently by Pullumbi et al. and Andrews et al., supporting the theoretical predictions. For n=6, we found the degenerate C2(2A) and Cs(2A′) MH2(H2)2 “double H2” type van der Waals complexes as the lowest energy species for both M=Al and Ga.Electronic Supplementary Material Supplementary material is available for this article at |
| |
Keywords: | Aluminum and gallium van der Waals complexes Ab initio calculations SAPT |
本文献已被 PubMed SpringerLink 等数据库收录! |
|