Imaging H abstraction dynamics in crossed molecular beams: O(³P) + propanol isomers

Abstract

Direct rebound dynamics are revealed for bimolecular reaction of the ground state O(3P) atom with propanol isomers, involving the post transition state long-range dipole–dipole interaction between the dipolar OH and hydroxypropyl radicals.

Comprehensive Investigations of the Cl + CH 3 OH → HCl + CH 3 O/CH 2 OH Reaction: Validation of Experiment and Dynamic Insights

“…A key question with these types of reactions is how the increasing size and complexity of Y will impact the reaction mechanism and dynamics. [11][12][13][14][15][16] This is an important and relevant question as we move toward heavier fuels for combustion engines. 17 However, it is still rather challenging to carry out reliable dynamical simulations of polyatomic reactions because of the high expenses of quantum chemical calculations, considerably more complex potential energy surfaces (PESs) with many degrees of freedom (DOFs), and difficult treatments of nuclear dynamics in high-dimensional space, especially when quantum effects are present.…”

Ab Initio and Quasiclassical Trajectory Study of the O(3P) + 2-Propanol Hydrogen Abstraction Reaction

“…To further calibrate the accuracy of the SRP-PM6 method with respect to other electronic structure methods beyond stationary points, we plot in Figure potential energy scans along the g-Cα pathway. Abstraction at Cα sites is particularly significant because product energy and angular distributions have been recently revealed for this pathway using molecular beam experiments . From the figure, one can see that SRP-PM6 is much more accurate than MP2 with the moderate cc-pVDZ basis set, which overestimates the barrier, and B3LYP with the same basis set, which exhibits an overly attractive entrance channel with a continuously downhill reaction path.…”

“…This agrees well with essential knowledge of hydrogen abstraction at carbon centers: the stability of an incipient carbon radical increases with the level of substitution, such that reaction at the tertiary Cα site is faster than at primary Cβ sites. , Reaction at O sites appears to show the highest barrier for both conformers, even though it is competitive with reaction at the highest-barrier Cβ sites. Importantly, given the molecular-beam experiments on the O + 2-propanol reaction used collision energies of 8.3 and 10.0 kcal/mol, the data in Figure a suggest reaction at Cα sites might dominate reactivity under those experimental conditions.…”

“…Using the SRP-PM6 Hamiltonian, we have propagated 45 000 direct-dynamics trajectories per conformer and set of initial conditions to investigate the reaction dynamics and examine the accuracy of the Hamiltonian in light of experiments. The experiments were carried out with an internally cold molecular beam of 2-propanol intercepted by photoinduced ground-state O atoms such that the collision energies were 8.3 and 10.0 kcal/mol . Consequently, our calculations consider rotationless 2-propanol with zero-point motion colliding with O at the same collision energies.…”

“…Comparison between simulated and measured product translational energy distributions for the O + 2-propanol Cα hydrogen abstraction channel at collision energies of 8.3 kcal/mol (top) and 10.0 kcal/mol (bottom).…”