Importance Of Exchange Processes Research Articles

Comprehensive Study of HCN: Potential Energy Surfaces, State-to-State Kinetics, and Master Equation Analysis.

Understanding the kinetics of the HCN system is critical to several disciplines in science and engineering, including interstellar chemistry, atmospheric reentry, and combustion, to name a few. This paper constructs a rovibrational state-specific kinetic mechanism for the HCN system, leveraging electronic structure calculations, classical scattering dynamics, and state-to-state kinetics. To this aim, three accurate potential energy surfaces (PESs), 1A', 3A', and 3A″, are constructed using multireference configuration interaction (MRCI) calculations for a comprehensive arrangement of the nuclei. Quasi-classical scattering calculations provide elementary reaction rate constants resulting from the interaction between the CN, CH, and NH molecules with H, N, and C atoms, respectively. The rovibrational collisional model developed comprises 50 million bound-bound and free-bound collisional processes. This model is used to study the dynamics of energy transfer and dissociation in an isochoric and isothermal chemical reactor via the solution of the master equation for a wide temperature range from 1000 to 10,000 K. This study unravels the dynamics of dissociation of the molecules in the HCN system, which the PESs primarily control via the formation of short-lived intermediates that shortcut the dissociation pathway. The exchange processes in CH and NH enhance the dissociation by over 80%. The importance of exchange processes is also highlighted in comparing the quasi-steady state and thermal dissociation rates with state-of-the-art rate models and experimental fits.

Resonating-group study and importance of exchange processes inN+O16scattering

The scattering of nucleons by $^{16}\mathrm{O}$ is studied with the resonating-group method and a generator-coordinate technique. The result shows that, at relatively high energies, the knockout process contributes significantly to the scattering amplitude, while the pickup process is of minor importance.NUCLEAR REACTIONS $^{16}\mathrm{O}(p, p)$, $E=37.4$ MeV; calculated $\ensuremath{\sigma}(\ensuremath{\theta})$ and $P(\ensuremath{\theta})$. Resonating-group method with generator-coordinate technique.

NLi6(α,d)Be8reaction and the importance of exchange processes

The $^{6}\mathrm{Li}(\ensuremath{\alpha},d)^{8}\mathrm{Be}_{\mathrm{g}.\mathrm{s}.}$ reaction is studied in the expectation that exchange contributions will be enhanced relative to the more usual light particle stripping process. Angular distributions of deuterons were measured at bombarding energies of 20 and 24 MeV and are found to exhibit back-angle peaking characteristic of the exchange process. Calculations including only a direct stripping mechanism are not able to account for the back-angle peaking and disagree with the back-angle data by more than two orders of magnitude. A two-mode finite-range distorted-wave Born-approximation analysis including cluster exchange contributions accurately describes the observed backward peaking at both energies. The importance of exchange contributions is attributed to favorable kinematic conditions and large cluster amplitudes associated with the exchange process.