Ab initio quantum mechanics of a cluster of SiH4 and two H2 molecules, together with its dimer and trimer

Recent experimental work by Strobel et al. [T.A. Strobel, M. Somayazulu, R.J. Hemley, Phys. Rev. Lett. 103 (2009) 065701] on a molecular solid subjected to high pressures has motivated the present study. We first investigate a molecular cluster containing one silane molecule plus two H2 molecules, by ab initio quantum mechanics. Geometrical and electronic structures for the ground state of such a cluster are thereby proposed. The di-cluster is next examined, and the coming together of two H2 molecules is predicted. Finally, the tri-cluster is studied and important aspects of the di-cluster bonding are found to remain largely intact