Erratum: “Direct molecular simulation of internal energy relaxation and dissociation in oxygen” [Phys. Fluids 31, 076107 (2019)]

First-principles predictions for shear viscosity of air components at high temperature

“…[2][3][4][5][6][7] Therefore, molecular simulation offers an attractive theoretical alternative to experiments, particularly when employed with ab initio potential energy surfaces (PESs) that describe atomic-level interactions between the various air particles. [8][9][10][11][12][13][14][15][16] Most studies based upon these first-principles PESs have focused on kinetic processes involving internal energy relaxation and its coupling to chemical reactivity, 9,[17][18][19][20] with considerable success in validating the results with the available experimental data. However, less work has been done to investigate their ability to predict transport properties.…”

Machine Learning Product State Distributions from Initial Reactant States for a Reactive Atom-Diatom Collision System

“…14 Hamilton's equations of motion were solved in reactant Jacobi coordinates using a fourth-order Runge-Kutta method with a time step of ∆t = 0.05 fs, which guarantees conservation of the total energy and angular momentum. 13,15 For generating the training, test, and validation data set for the NN the following statespecific initial conditions were used: (0.5 ≤ E trans ≤ 8.0) eV with ∆E trans = 0.5 eV; v = [0, 2,4,6,8,10,12,15,18,21,24,27,30,34,38]; and 0 ≤ j ≤ 225 with ∆j = 15, resulting in 2184 different states. The impact parameter b was sampled from 0 to b max = 12 a 0 using stratified sampling.…”

“…LG values between QCT and STD predictions for the product state distributions P (E int ) , P (v ), and P (j ) for given initial (v, j). The STD model was evaluated at fixed E trans = 4.0 eV for the grid points v = [0, 2,4,6,8,10,12,14] and j = [0, 15,30,45,60,75,90,105,120,135,150,165] used for training, validation, and testing.…”

“…state-to-state or STS) level quickly becomes computationally intractable using conventional approaches due to the rapid growth of the underlying state space. 2,3 As an example, even for a reactive atom+diatom system (A+BC→AB+C) the number of internal states for diatoms AB and BC is ∼ 10 4 which leads to ∼ 10 8 state-to-state cross sections σ v,j→v ,j (E trans ) between initial (v, j) and final (v , j ) rovibrational states at a given relative translational energy E trans . 3 The estimated number of classical trajectories required for converged STS cross sections is ∼ O (10 13 ) assuming that 10 5 classical trajectories are sufficient for one converged cross section.…”

“…For the initial condition (v = 13, j = 157) a comparatively high RMSD (∼ 0.005) is obtained (blue). For the corresponding R2 LG map, see FigureS2.…”