Kinetic isotope effects for dissociative recombination of tritiated ketenyl ion (3HCCO+): A surface-hopping ab initio molecular dynamics study

Richard A. Messerly; Brendan J. Gifford; Troy M. Holland

doi:10.1016/j.comptc.2022.113634

Kinetic isotope effects for dissociative recombination of tritiated ketenyl ion (³HCCO⁺): A surface-hopping ab initio molecular dynamics study

Richard A. Messerly, Brendan J. Gifford, Troy M. Holland

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

Dissociative recombination (DR) reactions are important when modeling charged species in the presence of free electrons. While experimental measurements of DR reaction rates are challenging, surface hopping ab initio molecular dynamics (SH-AIMD) simulations provide an attractive alternative. SH-AIMD is especially well-suited for estimating branching ratios, i.e., the relative rates of competing production channels, for DR reactions. Although the radiolysis of diatomic tritium has been studied experimentally, previous attempts to model these systems have failed to account for isotope effects in DR reactions. Previous SH-AIMD studies have also not investigated tritium isotope effects for the branching ratios of DR reactions. In this study, we compute the DR branching ratios of the protiated and tritiated ketenyl ion. Comparison with literature values for the protiated branching ratios provides confidence in the reliability of our SH-AIMD results. Our simulations predict a significant increase of the HC + CO branching ratio for the tritiated system.

Original language	English
Article number	113634
Journal	Computational and Theoretical Chemistry
Volume	1210
DOIs	https://doi.org/10.1016/j.comptc.2022.113634
State	Published - Apr 2022
Externally published	Yes

Funding

We would like to acknowledge Moritz Heindl and Sebastian Mai from the University of Vienna for their technical assistance with SHARC. We would like to acknowledge Samuel Battey of Los Alamos National Laboratory for sharing his invaluable expertise in multireference methods (CASSCF/CASPT2). This work was supported by the Laboratory Directed Research and Development Program at Los Alamos National Laboratory under project number 20210946DI. This research also used resources provided by the Los Alamos National Laboratory Institutional Computing Program, supported by the U. S. Department of Energy National Nuclear Security Administration under Contract No. 89233218CNA000001. This work was supported by the Laboratory Directed Research and Development Program at Los Alamos National Laboratory under project number 20210946DI. This research also used resources provided by the Los Alamos National Laboratory Institutional Computing Program, supported by the U. S. Department of Energy National Nuclear Security Administration under Contract No. 89233218CNA000001.

Keywords

Direct dynamics
Excited electronic states
Kinetic branching ratios
Multireference calculations
Reaction mechanisms

Access to Document

10.1016/j.comptc.2022.113634

Cite this

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title = "Kinetic isotope effects for dissociative recombination of tritiated ketenyl ion (3HCCO+): A surface-hopping ab initio molecular dynamics study",

abstract = "Dissociative recombination (DR) reactions are important when modeling charged species in the presence of free electrons. While experimental measurements of DR reaction rates are challenging, surface hopping ab initio molecular dynamics (SH-AIMD) simulations provide an attractive alternative. SH-AIMD is especially well-suited for estimating branching ratios, i.e., the relative rates of competing production channels, for DR reactions. Although the radiolysis of diatomic tritium has been studied experimentally, previous attempts to model these systems have failed to account for isotope effects in DR reactions. Previous SH-AIMD studies have also not investigated tritium isotope effects for the branching ratios of DR reactions. In this study, we compute the DR branching ratios of the protiated and tritiated ketenyl ion. Comparison with literature values for the protiated branching ratios provides confidence in the reliability of our SH-AIMD results. Our simulations predict a significant increase of the HC + CO branching ratio for the tritiated system.",

keywords = "Direct dynamics, Excited electronic states, Kinetic branching ratios, Multireference calculations, Reaction mechanisms",

author = "Messerly, {Richard A.} and Gifford, {Brendan J.} and Holland, {Troy M.}",

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doi = "10.1016/j.comptc.2022.113634",

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T2 - A surface-hopping ab initio molecular dynamics study

AU - Messerly, Richard A.

AU - Gifford, Brendan J.

AU - Holland, Troy M.

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N2 - Dissociative recombination (DR) reactions are important when modeling charged species in the presence of free electrons. While experimental measurements of DR reaction rates are challenging, surface hopping ab initio molecular dynamics (SH-AIMD) simulations provide an attractive alternative. SH-AIMD is especially well-suited for estimating branching ratios, i.e., the relative rates of competing production channels, for DR reactions. Although the radiolysis of diatomic tritium has been studied experimentally, previous attempts to model these systems have failed to account for isotope effects in DR reactions. Previous SH-AIMD studies have also not investigated tritium isotope effects for the branching ratios of DR reactions. In this study, we compute the DR branching ratios of the protiated and tritiated ketenyl ion. Comparison with literature values for the protiated branching ratios provides confidence in the reliability of our SH-AIMD results. Our simulations predict a significant increase of the HC + CO branching ratio for the tritiated system.

AB - Dissociative recombination (DR) reactions are important when modeling charged species in the presence of free electrons. While experimental measurements of DR reaction rates are challenging, surface hopping ab initio molecular dynamics (SH-AIMD) simulations provide an attractive alternative. SH-AIMD is especially well-suited for estimating branching ratios, i.e., the relative rates of competing production channels, for DR reactions. Although the radiolysis of diatomic tritium has been studied experimentally, previous attempts to model these systems have failed to account for isotope effects in DR reactions. Previous SH-AIMD studies have also not investigated tritium isotope effects for the branching ratios of DR reactions. In this study, we compute the DR branching ratios of the protiated and tritiated ketenyl ion. Comparison with literature values for the protiated branching ratios provides confidence in the reliability of our SH-AIMD results. Our simulations predict a significant increase of the HC + CO branching ratio for the tritiated system.

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