The dataset contains 44 molecular dynamic trajectories for the interaction of oxygen difluoride with a monohydrogenated silicon surface, computed using the CASTEP computer code. Output is provided in the form of *.md and *.castep files produced by the code. The former contains position, velocity, and force data, which may be visualised using commonly available software, such as the Jmol code. The latter contains human-readable data concerning electronic spin during each trajectory, together with sufficient information about computational parameters to enable replication of the calculations.