<i>Ab initio</i>study of the polymerisation of cyclopentasilane

Abstract

The molecular structures and vibration modes of cyclopentasilane (Si5H10) have been examined by employing ab initio and density-functional methods. Three different structures of Si5H10 with different symmetries are analysed, and the results show that the envelope (C s ) and the twist (C2) forms have similar energies and that the planar form (D5h ) is about 50 meV less stable than the C s and C2 forms. The excited-state potential energy surface of Si5H10 is performed using the CIS electronic energy calculation. The ring-open reaction of Si5H10 is investigated in detail by using the first-principles molecular-dynamics simulation for screening the reaction pathways. The formation of Si–H–Si is found to play an important role in the ring-open reaction.