The Role of Multifunctional Kinetics during Early-Stage Silicon Hydride Pyrolysis: Reactivity of Si₂H₂ Isomers with SiH₄ and Si₂H₆

Abstract

Kinetic parameters for the dominant pathways during the addition of the four Si(2)H(2) isomers, i.e., trans-HSiSiH, SiSiH(2), Si(H)SiH, and Si(H(2))Si, to monosilane, SiH(4), and disilane, Si(2)H(6), have been calculated using G3//B3LYP, statistical thermodynamics, conventional and variational transition state theory, and internal rotation corrections. The direct addition products of the multifunctional Si(2)H(2) isomers were monofunctional substituted silylenes, hydrogen-bridged species, and silenes. During addition to monosilane and disilane, the SiSiH(2) isomer was found to be most reactive over the temperature range of 800 to 1200 K. Revised parameters for the Evans-Polanyi correlation and a representative pre-exponential factor for multifunctional silicon hydride addition and elimination reaction families under pyrolysis conditions were regressed from the reactions in this study. This revised kinetic correlation was found to capture the activation energies and rate coefficients better than the current literature methods.

Systematic First-Principles Configuration-Interaction Calculations of Linear Optical Absorption Spectra in Silicon Hydrides: Si2H2n (n = 1–3)

“…obtained using millimeter-and submillimeter-wave spectroscopy, as also with their ab initio theoretical results. Our results are also in good agreement with the theoretical calculations reported by Gerv and Schaefer [37], Adamczyk and Broadbelt [76], Jursic, [39] and Sannigrahi and Nandi. [38] Atomic coordinates corresponding to the optimized geometry are presented in Table S9 of the Supporting Information.…”

“…7(c)). These values are in good agreement with those reported by McCarthy et al, [41] and Adamczyk et al [76] The atomic coordinates corresponding to our optimized geometry of this conformer are presented in Table S15 of…”

“…Peak III is due to two excited states, whose wave functions exhibit significant configuration mixing. The first state at 5.73 eV contributes the dominant intensity to the peak, and its wave function consists mainly of configurations Adamczyk and Broadbelt, [76] Grev and Schaefer, [37] Sannigrahi and Nandi, [38] Curtiss et al, [45] and Koseki and Gordon. [77] Atomic coordinates corresponding to our optimized geometry of this conformer are presented in Table S10 of the Supporting Information.…”

Data‐Driven Investigation of Monosilane and Ammonia Co‐Pyrolysis to Silicon‐Nitride‐Based Ceramic Nanomaterials

“…The G3//B3LYP level of theory was also preferred for self-consistency because our previous studies used the same level of theory . [33][34][35][36][37] In this study, however, due to a large electronegativity difference between N/Si and N/H atoms, more flexible basis sets were potentially needed and explored. For this purpose, we added different levels of polarization functions and diffusion functions to the B3LYP functional.…”

“…In short, the singlet state was lowest energy electronic wavefunctions used in our investigation, and the G3/B3LYP composite method was most accurate for thermochemistry prediction against available experimental data for Si and N containing hydrides. The G3//B3LYP level of theory was also preferred for self‐consistency because our previous studies used the same level of theory [33–37] . In this study, however, due to a large electronegativity difference between N/Si and N/H atoms, more flexible basis sets were potentially needed and explored.…”