Unraveling Photodimerization of Cyclohexasilane from Molecular Dynamics Studies

Photoinduced
reactions of a pair of cyclohexasilane (CHS) monomers
are explored by time-dependent excited-state molecular dynamics (TDESMD)
calculations. In TDESMD trajectories, one observes vivid reaction
events including dimerization and fragmentation. A general reaction
pathway is identified as (i) ring-opening formation of a dimer, (ii)
rearrangement induced by bond breaking, and (iii) decomposition through
the elimination of small fragments. The identified pathway supports
the chemistry proposed for the fabrication of silicon-based materials
using CHS as a precursor. In addition, we find dimers have smaller
HOMO–LUMO gaps and exhibit a red shift and line-width broadening
in the computed photoluminescence spectra compared with a pair of
CHS monomers.