Eur. Phys. J. D 53, 309-317 (2009)
https://doi.org/10.1140/epjd/e2009-00141-6

Interaction of Ga₃ cluster with molecular hydrogen: combined DFT and CCSD(T) theoretical study

Faculty of Chemistry, Wroclaw University, F. Joliot-Curie 14, 50-383 Wroclaw, Poland

Corresponding author: ^a jmoc@wchuwr.chem.uni.wroc.pl

Received: 15 October 2008
Revised: 31 March 2009
Published online: 1 May 2009

Abstract

We have explored the lowest doublet and quartet potential energy surfaces (PES) for the reaction of gallium trimer with H₂. This reaction was studied experimentally by Margrave and co-workers in a noble gas matrix. The detailed reaction paths ending up with the low-energy Ga₃H₂ hydride isomers have been predicted based on the high level ab initio coupled-cluster calculations (CCSD(T)) with large basis set. We have found that the reaction occuring on the lowest doublet PES is described by the activation barrier for H₂ cleavage of about 15 kcal/mol, consistent with experiment. In the most stable Ga₃H₂ hydride structure, whose formation is exothermic by 15 kcal/mol, both H atoms assume three-fold bridged positions. The diterminal planar structure of Ga₃H₂, proposed experimentally from the observed IR spectra, is found to be only 1 kcal/mol less stable than the dibridged form.