Quasi-classical trajectory and quantum mechanics study of the reaction H(2S)+NH→N(4S)+H2

Progress and Prospective of Nitrogen-Based Alternative Fuels

Alternative fuels are essential to enable the transition to a sustainable and environmentally friendly energy supply. Synthetic fuels derived from renewable energies can act as energy storage media, thus mitigating the effects of fossil fuels on environment and health. Their economic viability, environmental impact, and compatibility with current infrastructure and technologies are fuel and power source specific. Nitrogen-based fuels pose one possible synthetic fuel pathway. In this review, we discuss the progress and current research on utilization of nitrogen-based fuels in power applications, covering the complete fuel cycle. We cover the production, distribution, and storage of nitrogen-based fuels. We assess much of the existing literature on the reactions involved in the ammonia to nitrogen atom pathway in nitrogen-based fuel combustion. Furthermore, we discuss nitrogen-based fuel applications ranging from combustion engines to gas turbines, as well as their exploitation by suggested end-uses. Thereby, we evaluate the potential opportunities and challenges of expanding the role of nitrogen-based molecules in the energy sector, outlining their use as energy carriers in relevant fields.

The effect of intersystem crossings in N((2)D) + H2 collisions

The transitions between quartet and doublet states of the NH2 molecule are studied for the first time, allowing the evaluation of the N((4)S) + H2 reactive channel. High level ab initio calculations of the spin-orbit coupling are performed over the whole configurational space of the NH2 molecule and fitted to a proposed analytic form. Quasiclassical trajectories coupled with the surface hopping method are employed to calculate reaction cross section and rate constants. The reaction is largely affected by the initial rovibrational states of H2, while the formation of long-lived complexes enhances the reaction probability.

Energy-dependent stereodynamics for the H(2S)+NH(X3)→H2(X1Σg+)+N(4S) reaction on the improved ZH potential energy surface

In this work, quasi-classical trajectory (QCT) calculations have been first carried out for the title reaction on a new global potential energy surface for the lowest quartet electronic state, 4A″. The average rotational alignment factor [P2(j'·k)] as a function of collision energy and the two commonly used polarization dependent generalized differential cross sections PDDCS00, PDDCS20, have been calculated in the center-of-mass (CM) frame, separately. Three angular distributions, P(θr), P(φr), and P(θr, φr) are also calculated to gain insight into the alignment and the orientation of the product molecules. Calculations show that the average rotational alignment factor on the ZH PES is almost invariant with collision energies. The distributions of P(θr) and P(φr) derived from the title reaction indicate that the product polarization is strong. Validity of the QCT calculation has been examined and proven in the comparison with the quantum-wave-packet calculation results. Comparisons with available quasi-classical trajectory results are made and discussed.

QUASICLASSICAL TRAJECTORY STUDY OF PRODUCT POLARIZATIONS IN THE H(2S) + NH → N(4S) + H2 REACTION

Based on the DMBE potential surface of the 4 A ″ ground-state, the product rotational polarizations in the title reaction are studied by using quasiclassical trajectory (QCT) calculation method. Three angular distributions of P(θr), P(Φr), P(θr, Φr) and the four polarization-dependent differential cross sections (PDDCSs) were calculated for the collision energy range of 1–20 kcal/mol. The results revealed that the product is backward-scattering and the product rotational angular momentum j′ is aligned and oriented. With the increment of collision energy, the degree of the product alignment and orientation is enhanced, showing the collision energy-dependent behaviors of the product polarizations.

INFLUENCE OF VIBRATIONAL EXCITATION AND COLLISION ENERGY ON THE STEREO DYNAMICS OF THE REACTIONS: N(4S)+H2(v = 0-3,j = 0) → NH(X3Σ-)+H

Quasi-classical trajectory (QCT) calculations have been carried out to study the stereodynamics of the title reactions, using the double many-body expansion (DMBE) potential energy surface (PES) constructed by Poveda [Poveda LA, Varandas AJC, Phys. Chem. Chem. Phys.7:2867, 2005]. Vector correlations, such as the distributions of the polarization-dependent differential cross-sections (PDDCSs), the angular distributions of P(θr), P(ϕr), P(θr,ϕr), and the product alignment parameter P2( cos θr) are reported within the energy range of 25–140 kcal mol-1. The influences of the collision energy and the initial state-selected vibrational excitation are discussed in detail. In addition, Validity of the current QCT calculations is also examined and compared with the revelant results reported by Pascual et al. [Pascual RZ, Schatz GC, Lendvay G, Troya D, J. Phys. Chem. Aਠ106:4125, 2002].

EFFECT OF THE REACTANT ALIGNMENT ON STEREODYNAMICS FOR THE REACTION F + OH

Quasi-classical trajectory (QCT) calculations are performed for the reaction F + OH → HF + O based on the adiabatic potential-energy surface (PES) of the 13A″ triplet state. The reaction probability as a function of incident angle has been presented. The differential cross sections (DCSs), the distribution of angle between k and j′, P(θr) and the distribution of dihedral angle denoting k – k′ – j′ correlation, P(ϕr) have also been calculated at the different incident angles in the center-of-mass (CM) frame, respectively. The effects of reactant alignment on stereodynamics of the reaction are firstly revealed, which provides the theoretical foundation for the related experiment and enriches the theories of the stereodynamics.

THEORETICAL STUDY OF STEREODYNAMICS AND ISOTOPIC EFFECTS FOR THE REACTION C(3P) + OD(X2Π) → CO(X1Σ+) + D(2S)

Theoretical study on stereodynamics for the title reaction as well as its isotopic effects has been studied via QCT calculations on the ground X2A′ state of ab initio potential energy surface according to the study by Zanchet et al. Four polarization-dependent generalized differential cross-sections PDDCSs ((2π/σ) (dσ00/dωt), (2π/σ)(dσ20/dωt)), (2π/σ)(dσ22+/dωt), (2π/σ)(dσ21-/dωt), and the distributions of P(θr) and P(φr) that denotes the correlations of k-j′ and k-k′-j′ are presented in this work. Product angular distribution and rotational polarization have been analyzed at different collision energies and compared with C+OH reaction. Product angular distribution shows strong forward scattering at low collision energy and becomes more symmetric with forward and backward scattering with the increasing collision energy. The alignment and orientation of product angular momentum presents a different behavior with collision energy, the former one increases monotonically with collision energy, whereas the latter one shows first decreasing and then increasing behavior, which have been analyzed in the present paper. Product rotational polarization for C+OD is weaker than that for C+OH , which is mainly due to the mass factor and zero point energy of C+OD .