Hypersonic impact properties of pristine and hybrid single and multilayer C3N and BC3 nanosheets
Summary¶
Classical molecular dynamics in LAMMPS models C\(_{60}\) projectile impacts on C\(_3\)N and BC\(_3\) monolayers and multilayers using Tersoff interactions for intralayer bonding (parameters from Kinaci et al. as cited) and Lennard–Jones for interlayer vdW gaps. After NPT equilibration at 300 K (Nosé–Hoover, 0.25 fs timestep, 50 ps), C\(_{60}\) is launched along \(z\) toward fixed edge atoms. The study maps ballistic curves, residual velocities, and energy absorption versus impact speed, layer count, spacing, and C\(_3\)N/BC\(_3\) stacking, reporting that C\(_3\)N can absorb more energy than BC\(_3\) at high speed due to stronger N–C vs B–C bonding, with hybrid stacks improving BC\(_3\) performance.
Methods¶
MD application (classical, ballistic impact). LAMMPS runs NPT equilibration at 300 K (Nosé–Hoover as stated in the article) for C\(_3\)N and BC\(_3\) monolayers and multilayers, then NVE-style impact segments (post-equilibration) where a C\(_{60}\) projectile is given initial velocity along z toward the sheet. Velocity Verlet integration with Δt = 0.25 fs; equilibration 50 ps (per the article’s “Computational methods” table). Tersoff parameters from Kinaci et al. (cited) describe intralayer C–B / C–N / C–C bonding; Lennard–Jones 12-6 terms with Lorentz–Berthelot mixing (Table 1) treat interlayer van der Waals interactions. A representative monolayer patch is about 6×6 nm\(^2\) with PBC in plane; one edge row of atoms is fixed in x,y to anchor the target; initial projectile–sheet gap 5 nm; total atom count 1404 in the documented monolayer example (1068 C including 60 in C\(_{60}\), 336 B/N in the monolayer sheet). Barostat — used in NPT equilibration only. Production impact — NVE (no thermostat on the colliding system as described for the strike protocol). Electric field / enhanced sampling — N/A. Electrostatics — Tersoff+LJ; N/A long-range Ewald beyond the LJ model as described. Shock — hypersonic impact speeds span the paper’s parametric table (see Table 2 / Figs. 2–3 for residual speed vs impact speed).
Force-field training. N/A — uses published Tersoff + LJ parameters; no refit in this work.
Static QM. N/A — not used.
Findings¶
Outcomes and mechanisms. The study maps ballistic curves and residual velocities for C\(_{60}\) impacts on C\(_3\)N and BC\(_3\); C\(_3\)N can absorb more energy at high impact speeds, linked in the paper to stronger N–C vs B–C bonding. At lower speeds before penetration, single-layer responses are more similar. Decomposition of kinetic energy into bond stretching vs interlayer slip is discussed qualitatively through the Tersoff+LJ partition—N/A reactive bond-making chemistry in this classical stack.
Comparisons and sensitivity. Hybrid stacks with alternating C\(_3\)N/BC\(_3\) multilayers can outperform homogeneous BC\(_3\) stacks in the reported energy-absorption metrics. Sensitivity to layer count, interlayer spacing, and initial projectile velocity is tabulated in the article; N/A — direct experiment or shock-tube validation in this computational paper (the authors do not claim quantitative agreement with macro-scale experiments here). Strain rate and shock invariant comparisons are N/A beyond the stated C\(_{60}\) ballistic setup.
Limitations (as implied by the model class). Tersoff+LJ omits bond-breaking chemistry and charge transfer; transferability of parameters to other projectiles or alloys is uncertain without further benchmarks (see ## Limitations below for this wiki note).
Limitations¶
Tersoff+LJ models omit bond-breaking chemistry (contrast with ReaxFF reactive studies); parameter transferability at extreme impact speeds should be benchmarked against experiment or higher-level theory.
Relevance to group¶
Non-ReaxFF ballistic MD benchmark of 2D nitride/boride sheets—useful contrast to reactive workflows in the corpus.
Citations and evidence anchors¶
- Sci. Rep. 11, 7972 (2021); “Computational methods” and Table 1–2.