Ring‐polymer Molecular Dynamics Simulation for the Adsorption of H₂ on Ice Clusters (H₂O)_n (n=8, 10, and 12)

Abstract

In the interstellar medium, the H 2 adsorption and desorption on the solid water ice are crucial for chemical and physical processes. We have recently investigated the probabilities of H 2 sticking on the (H 2 O) 8 ice, which has quadrilateral surfaces. We have extended the previous work using classical MD and ringpolymer molecular dynamics (RPMD) simulations to the larger ice clusters, (H 2 O) 10 and (H 2 O) 12 , which have pentagonal and hexagonal surfaces, respectively. The H 2 sticking probabilities decreased as the temperature increased for both cluster cases, whereas the cluster-size-independent profiles were observed. It is thought that the size independence of the probabilities is qualitatively understood from the similar binding energies for all the three cluster systems. Furthermore, the RPMD sticking probabilities are smaller than the classical ones because of the reduction in the binding energies owing to nuclear quantum effects, such as vibrational quantization.

Theoretical Study of the Thermal Rate Coefficients of the H3+ + C2H4 Reaction: Dynamics Study on a Full-Dimensional Potential Energy Surface

“…The integration of the equations of the motion of the ring polymer Hamiltonian was carried out using the velocity–Verlet method with a time step of Δ t = 0.10 fs, totaling 10 4 –10 6 simulation steps. Subsequently, RPMD simulations were performed, extending the PIMD method to enable real-time dynamics simulations, which are particularly adept at capturing nuclear quantum effects, such as zero-point energy and tunneling [ 30 , 36 , 44 , 45 , 46 , 47 , 48 , 49 ]. The impact parameter ( b ) for collisional simulations was set below b = b max ζ 1/2 , where b max represents the maximum impact parameter, and ζ is a random number within the range of [0, 1].…”

Computational study of the post-transition state dynamics for the OH + CH3OH reaction probed by photodetachment of the CH3O−(H2O) anion

“…33,34 The quantum and classical Boltzmann distribution around the equilibrium structure was achieved using path-integral molecular dynamics (PIMD) approach. Subsequently, we performed real-time propagated simulations of dissociative photodetachment dynamics on the neutral PESs from Franck-Condon region using the RPMD technique, [35][36][37][38][39][40][41][42][43][44][45] as well as classical MD. The paper centers its discussion on the influence of Franck-Condon overlap characteristics between the anion and neutral PESs, alongside the influence of neutral PES landscapes, on dissociation dynamics.…”

Machine learning‐assisted study of correlation between post‐transition‐state bifurcation and initial phase information at the ambimodal transition state

“…Therefore, the RPMD method can approximately describe nuclear quantum effects such as zero‐point energy and tunneling 15–19 . The accuracy of the RPMD calculations is well established because they were applied to various chemical reactions in many previous studies 20–40 . In contrast with the RPMD, the quasi‐classical trajectory (QCT) method 41,42 has been extensively employed in the reaction dynamics field.…”