Ab initio quantum mechanical methods, including the self-consistent field (SCF), single and double excitation configuration interaction (CISD), the single and double excitation coupled cluster (CCSD), and the single, double, and perturbative triple excitation coupled cluster [CCSD(T)] have been applied to study the ground-state cyanovinylidene-cyanoacetyleneisomerization reaction. The classical barrier for the isomerization from cyanovinylidene to cyanoacetylene is found to be 4.3 kcal/mol and is 2.2 kcal/mol when the zero-point vibrational energy corrections are included. Cyanovinylidene is predicted to lie 47 kcal/mol higher in energy than cyanoacetylene. Some comparisons of cyanovinylidene with vinylidene and fluorovinylidene are presented and suggest that cyanovinylidene is a genuine minimum on the potential energy hypersurface. Thus, the probability of observing cyanovinylidene spectroscopically is substantial, particularly via negative ion photodetachment spectroscopy. Two low-lying triplet states ã3A′ and b̃3A″ of cyanovinylidene have also been studied.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry