Thake Henry, Jenkins Stephen J
Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
Phys Chem Chem Phys. 2025 Jan 2;27(2):660-671. doi: 10.1039/d4cp03375b.
We present first-principles molecular dynamics simulations of oxygen difluoride impinging upon the monohydrogenated Si{001}(2 × 1) surface. Adsorption occurred in fewer than 10% of our computed trajectories, but in each reactive case the initial step involved partial dissociation to yield an adsorbed fluorine atom and a free oxygen monofluoride radical. In one trajectory, the adsorbed fluorine atom displaced a hydrogen atom into an unusual Si-H-Si bridge position, consistent with three-centre two-electron bonding. In another, a Si-Si-F motif was created, consistent with three-centre four-electron bonding. Depending upon its recoil direction, the ubiquitous monofluoride species either migrated across the surface before itself reacting to form a Si-O-Si bridge and a second adsorbed fluorine atom, or desorbed intact as a gas-phase radical.
我们展示了二氟化氧撞击氢化硅{001}(2×1)表面的第一性原理分子动力学模拟。在我们计算的轨迹中，吸附发生的情况不到10%，但在每个反应案例中，初始步骤都涉及部分解离，产生一个吸附的氟原子和一个游离的一氟氧自由基。在一条轨迹中，吸附的氟原子将一个氢原子置换到一个不寻常的Si-H-Si桥位，这与三中心两电子键合一致。在另一条轨迹中，形成了一个Si-Si-F基序，这与三中心四电子键合一致。取决于其一氟化物物种的反冲方向，它要么在自身反应形成Si-O-Si桥和第二个吸附的氟原子之前在表面迁移，要么作为气相自由基完整地解吸。
