Proton Transfer vs Complex Formation Channels in Ionized Formic Acid Dimer: A Direct <i>Ab Initio</i> Molecular Dynamics Study

Tachikawa, Hiroto

doi:10.1021/acs.jpca.0c01729

Cited by 16 publications

(21 citation statements)

References 25 publications

(43 reference statements)

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“…The total energy drift in all trajectory calculations was less than 0.01 kcal/mol. Direct AIMD calculations were carried out using our own code. − Similar calculations were carried out for O( 3 P)(H 2 O) n and O( 1 D)(H 2 O) n .…”

Section: Computational Detailsmentioning

confidence: 99%

Formation of Hydrogen Peroxide from O^–(H₂O)_n Clusters

Tachikawa

2021

J. Phys. Chem. A

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Hydrogen peroxide (H2O2) has recently received much attention as a safe and clean energy carrier for hydrogen molecules. In this study, based on direct ab initio molecular dynamics (AIMD) calculations, we demonstrated that H2O2 is directly formed via the photoelectron detachment of O–(H2O) n (n = 1–6) (water clusters of an oxygen radical anion). Three electronic states of oxygen atoms were examined in the calculations: O(X)(H2O) n (X = 3P, 1D, and 1S states). After the photoelectron detachment of O–(H2O) n (n = 1) to the 1S state, a complex comprising O(1S) and H2O, O(1 S)-OH2, was formed. A hydrogen atom of H2O immediately transferred to O(1S) during an intracluster reaction to form H2O2 as the final product. Simulations were run to obtain a total of 33 trajectories for n = 1 that all led to the formation of H2O2. The average reaction time of H2O2 formation was calculated to be 57.7 fs in the case of n = 1, indicating that the reaction was completed within 100 fs of electron detachment. All the reaction systems O(1S)(H2O) n (n = 1–6) indicated the formation of H2O2 by the same mechanism. The reaction times for n = 2–6 were calculated to range between 80 and 180 fs, indicating that the reaction for n = 1 is faster than that of the larger clusters, that is, the larger the cluster size, the slower the reaction is. The reaction dynamics of the triplet O(3P) and singlet O(1D) potential energy surfaces were calculated for comparison. All calculations yielded the dissociation product O(X)(H2O) n → O(X) + (H2O) n (X = 3P and 1D), indicating that the O(1S) state contributes to the formation of H2O2. The reaction mechanism was discussed based on the theoretical results.

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Section: Computational Detailsmentioning

confidence: 99%

Formation of Hydrogen Peroxide from O^–(H₂O)_n Clusters

Tachikawa

2021

J. Phys. Chem. A

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“…Direct AIMD calculations of the neutral NF 3 –CH 3 Cl cluster were carried out at a constant temperature (10 K) to generate the initial geometries of the structure in the vertical electron capture state, [(NF 3 –CH 3 Cl) − ] ver . 46 The Nosé–Hoover algorithm was used to maintain a constant temperature in each trajectory. 47,48 The direct AIMD calculations of [(NF 3 –CH 3 Cl) − ] ver were performed on selected geometries at the CAM-B3LYP/6-311++G(d,p) level of theory.…”

Section: Methodsmentioning

confidence: 99%

Reaction mechanism of an intracluster S_N2 reaction induced by electron capture

Tachikawa¹

2022

Phys. Chem. Chem. Phys.

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“…The total energy drifts in all trajectory calculations were less than 0.01 kcal/mol. The direct AIMD calculations were carried out using our own code. ,, …”

Section: Computational Detailsmentioning

confidence: 99%

“…In the present study, reactions of [PhOH–(NH 3 ) n ] + ( n = 1–5), following ionization of neutral clusters, were investigated using a direct AIMD method. , We focus mainly on the reaction rate of a PT after ionization and its reaction mechanism. Scheme shows an illustration of the potential energy curves for the photoreaction of PhOH–(NH 3 ) n derived from previous studies.…”

Section: Introductionmentioning

confidence: 99%

Proton Transfer Reaction Rates in Phenol–Ammonia Cluster Cation

Tachikawa

Iyama

2020

J. Phys. Chem. A

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Proton transfer (PT) in an interaction system of a hydroxyl–amino group (OH–NH) plays a crucial role in photoinduced DNA and enzyme damage. A phenol–ammonia cluster is a prototype of an OH–NH interaction and is sometimes used as a DNA model. In the present study, the reaction dynamics of phenol–ammonia cluster cations, [PhOH–(NH3) n ]+ (n = 1–5), following ionization of the neutral parent clusters, were investigated using a direct ab initio molecular dynamics (AIMD) method. In all clusters, PTs from PhOH+ to (NH3) n were found postionization, the reaction of which is expressed as PhOH+–(NH3) n → PhO–H+(NH3) n . The time of the PT was calculated as 43 (n = 1), 26 (n = 2), and 13 fs (n = 3–5), suggesting that the rate of PT increases with an increase in n and is saturated at n = 3–5. The difference in the PT rate originates strongly from the proton affinity of the (NH3) n cluster. In the case of n = 3–5, a second PT was found, the reaction of which is expressed as PhO–H+(NH3) n → PhO–NH3–H+(NH3) n−1, and a third PT occurred at n = 4 and 5. The time of the PT was calculated as 10–13 (first PT), 80–100 (second PT), and 150–200 fs (third PT) in the case of larger clusters (n = 4 and 5). The reaction mechanism based on the theoretical results is discussed herein.

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Proton Transfer vs Complex Formation Channels in Ionized Formic Acid Dimer: A Direct Ab Initio Molecular Dynamics Study

Cited by 16 publications

References 25 publications

Formation of Hydrogen Peroxide from O^–(H₂O)_n Clusters

Formation of Hydrogen Peroxide from O^–(H₂O)_n Clusters

Reaction mechanism of an intracluster S_N2 reaction induced by electron capture

Proton Transfer Reaction Rates in Phenol–Ammonia Cluster Cation

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Proton Transfer vs Complex Formation Channels in Ionized Formic Acid Dimer: A Direct Ab Initio Molecular Dynamics Study

Cited by 16 publications

References 25 publications

Formation of Hydrogen Peroxide from O–(H2O)n Clusters

Formation of Hydrogen Peroxide from O–(H2O)n Clusters

Reaction mechanism of an intracluster SN2 reaction induced by electron capture

Proton Transfer Reaction Rates in Phenol–Ammonia Cluster Cation

Contact Info

Product

Resources

About

Formation of Hydrogen Peroxide from O^–(H₂O)_n Clusters

Formation of Hydrogen Peroxide from O^–(H₂O)_n Clusters

Reaction mechanism of an intracluster S_N2 reaction induced by electron capture