The reaction of ground state atomic carbon with silane under single collision conditions was investigated theoretically to unravel the nonadiabatic dynamics. The likely channels on the adiabatic triplet and singlet ground-state potential energy surfaces of CSiH4.are explored. The geometries of collision complex, intermediates, transition states, H and H2 dissociation products are optimized along with the harmonic frequencies by employing coupled cluster CCSD/cc-pVTZ calculations. The energies are extrapolated to completed basis set limits, CCSD(T)/CBS. The minimum energy crossing point between triplet and singlet surfaces is located with CPMCSCF/TZVPP method. The product branching ratios were predicted utilizing RRKM theory. The calculations revealed the reaction involving a van der Waals complex upon entrance, nonadiabatic dynamics along with intersystem crossing (ISC) to the singlet manifold, and eventually the synthesis of products via molecular and atomic hydrogen loss and elimination, which is kinetic control rather than the thermodynamics. The good agreement between crossed molecular beam experiments and theory implies that quantum and statistical computations have reached a level to predict nonadiabatic processes involving third-row element. The underlying dynamics of the carbon – silane reaction are quite distinct from the isovalent silicon - silane and carbon – methane systems.

Nonadiabatic dynamics of C(3P) + SiH4 reaction

253rd National Meeting (2017)

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