Combined Crossed Molecular Beams and Ab Initio Study of the Bimolecular Reaction of Ground State Atomic Silicon (Si; 3P) with Germane (GeH4; X1A1). Issue 14 (10th June 2021) - Krasnoukhov, Vladislav S.
Abstract: The chemical dynamics of the elementary reaction of ground state atomic silicon (Si; 3 P) with germane (GeH4 ; X 1 A1 ) were unraveled in the gas phase under single collision condition at a collision energy of 11.8±0.3 kJ mol −1 exploiting the crossed molecular beams technique contemplated with electronic structure calculations. The reaction follows indirect scattering dynamics and is initiated through an initial barrierless insertion of the silicon atom into one of the four chemically equivalent germanium‐hydrogen bonds forming a triplet collision complex (HSiGeH3 ; 3 i1 ). This intermediate underwent facile intersystem crossing (ISC) to the singlet surface (HSiGeH3 ; 1 i1 ). The latter isomerized via at least three hydrogen atom migrations involving exotic, hydrogen bridged reaction intermediates eventually leading to the H3 SiGeH isomer i5 . This intermediate could undergo unimolecular decomposition yielding the dibridged butterfly‐structured isomer 1 p1 (Si(μ‐H2 )Ge) plus molecular hydrogen through a tight exit transition state. Alternatively, up to two subsequent hydrogen shifts to i6 and i7, followed by fragmentation of each of these intermediates, could also form 1 p1 (Si(μ‐H2 )Ge) along with molecular hydrogen. The overall non‐adiabatic reaction dynamics provide evidence on the existence of exotic dinuclear hydrides of main group XIV elements, whose carbon analog structures do not exist. Abstract : Exotic dinuclear hydrides : The chemical dynamics of the elementary reaction of ground state atomic silicon with germane unraveled in the gas phase under single collision condition exploiting the crossed molecular beams technique contemplated with electronic structure calculations provide evidence on the existence of exotic dinuclear hydrides of main group XIV elements, such as (Si(μ‐H2 )Ge), whose carbon analog structures do not exist. The product formation involves facile intersystem crossing from triplet to singlet surface followed by elimination of molecular hydrogen.