Full-dimensional quantum dynamics study of vinylidene–acetylene isomerization: a scheme using the normal mode Hamiltonian

Abstract

Full-dimensional quantum dynamics calculations of vinylidene–acetylene isomerization are performed and the state-specific resonance decay lifetimes of vinylidene(-d₂) are computed. The theoretical scheme is a combination of several methods: normal coordinates are chosen to describe the nuclear motion of vinylidene, with both the parity and permutation symmetry exploited; phase space optimization in combination with physical considerations is used to generate an efficient discrete variable representation; the reaction coordinate is defined by us according to the three most relevant normal coordinates, along which a kind of optimal complex absorbing potential is imposed; the preconditioned inexact spectral transform method combined with an efficient preconditioner is employed to extract the energies and lifetimes of vinylidene. The overall computation is efficient. The computed energy levels generally agree with experiment well, and several state-specific lifetimes are reported for the first time.