Fragmentation dynamics of CH3Clq+ (q = 2,3): theory and experiment

Bhatt, Pragya; Maiyelvaganan, K. Rudharachari; Prakash, M.; Palaudoux, J.; Safvan, C. P.; Hochlaf, M.

doi:10.1039/d2cp02194c

Cited by 3 publications

(9 citation statements)

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“…However, the reactions of eqs and did not occur in molecular dynamics simulations because the excess energy provided by the vertical ionization is insufficient to exceed TS7 Cl and TS8 Cl , which are energetically higher than the ionized state of 1 Cl . For the formation of Cl + , the contribution of excited electronic states of the ionized molecule is experimentally suggested …”

Section: Resultsmentioning

confidence: 99%

“…For the formation of Cl + , the contribution of excited electronic states of the ionized molecule is experimentally suggested. 26 The potential energy profiles of all reaction paths, including the vertical ionization to the divalent cation for Cl, are shown in Figure 6. The relative energies at the CASPT2, CCSD, and MP2 levels are very similar to each other for the H + , H 2 + , and H 3 + formation and the H migration.…”

Section: Ts8mentioning

confidence: 99%

“…7,25−30 Furthermore, researchers have conducted computational studies to elucidate the mechanism behind the H 3 + formation 7,25,26 as well as the H + and H 2 + formation and to explore multiple fragmentation pathways leading to various products, including those that involve H-migration. 7,26 Recently, the examination has been extended to include the triply ionized CH 3 Cl 3+ in addition to the doubly ionized CH 3 Cl 2+ as a parent ion, and has covered not only ground state but also the excited state of their parent ions. 26 However, despite the significant amount of studies that have been conducted, there remains a lack of thorough examination regarding the dynamic process of fragmentation.…”

Section: ■ Introductionmentioning

confidence: 99%

“…7,26 Recently, the examination has been extended to include the triply ionized CH 3 Cl 3+ in addition to the doubly ionized CH 3 Cl 2+ as a parent ion, and has covered not only ground state but also the excited state of their parent ions. 26 However, despite the significant amount of studies that have been conducted, there remains a lack of thorough examination regarding the dynamic process of fragmentation. We therefore focused on the fact that the proportion of H 3 + in the product is relatively small, as previously reported for divalent methanol, 2,13 ethane, 6 and methyl chloride, 7,8 and anticipated that some dynamic effects would play a role in controlling the product distribution for ionization-induced reactions as well as for the photoreaction.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The ionization-induced fragmentation of methyl halides is of great interest, because the methyl chloride is present in the stratosphere and interstellar medium and contributes to ozone depletion in the stratosphere. For this reason, numerous experimental and theoretical studies have been intensively conducted, with particular emphasis on the two important processes: (i) ionization − and (ii) subsequent fragmentation reaction, ,,− which together constitute the ionization-induced fragmentation reaction. Many experiments have shown that the doubly ionized methyl chloride yields not only H + and H 2 + but also H 3 + as well as other substances such as HCl + and Cl + .…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

Matsubara

2023

J. Phys. Chem. A

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The mechanisms of the ionization-induced fragmentation and H migration of methyl halides CH 3 X (X = F, Cl, Br) have been examined by quantum mechanical and molecular dynamics methods. When CH 3 X (X = F, Cl, Br) is vertically ionized into a divalent cation, it can obtain enough excess energy to overcome the energy barrier of subsequent reaction channels for the formation of H + , H 2 + , and H 3 + species and intramolecular H migration. The product distributions of these species greatly depend on the halogen atoms. The H + formation decreases in the order of F > Cl > Br, which is inversely proportional to the increase in the magnitude of the energy barrier in the order of Br > Cl > F. This is attributable to the change in the charge distribution of the entire molecule by the halogen atoms. Meanwhile, the small H migration ratio for Cl and Br, despite their low energy barriers, was explained by the small sum of states at the transition state based on the Rice−Ramsperger−Kassel− Marcus (RRKM) theory. The H 3 + formation ratio is unexpectedly smaller despite its low energy barrier. This is attributed to the dynamic effects of the H 2 roaming that always occur prior to the reaction in question. Molecular dynamics simulations showed that the H 2 roaming was restricted in a certain area due to an initially produced driving force on the hydrogen atoms in a certain direction by vertical ionization; this phenomenon suppresses the formation of H 3 + , which requires the hydrogen atoms to be in motion over a relatively wide range to enter the transition state region. Thus, the low proportion of the observed H 3 + can be explained by the dynamical probability of the transition state structure formation.

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Section: Resultsmentioning

confidence: 99%

Section: Ts8mentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

Matsubara

2023

J. Phys. Chem. A

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Probing Conical Intersection in the Multipathway Isomerization of CH₃Cl Using Coulomb Explosion

Guo,

Zhang,

Dong

et al. 2024

J. Phys. Chem. Lett.

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Ubiquitous ultrafast isomerization is paramount in photoexcited molecules, in which non-adiabatic coupling among multiple electronic states can occur. We use the pump− probe Coulomb explosion imaging method to study the isomerization of CH 3 Cl molecules. We find that the isomerization under our strong field pump−probe scheme proceeds along multiple pathways, which are encoded in several distinct branches of the time-resolved kinetic energy release spectra for the CH 2 + +HCl + Coulomb explosion channel. Apart from the isomerized dissociative pathway in neutral and cationic excited states, the pump laser can also induce coherent vibrational dynamics in two coupled intermediate states and set up the initial conditions for the two concurrently proceeding isomerization pathways. The isomerization of CH 3 Cl provides an intriguing example of a chemical reaction consisting of multiple pathways and non-adiabatic dynamics.

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Energy-dependent photoion angular distributions in two-body Coulomb explosions of molecules

Guo,

Li,

et al. 2024

The Journal of Chemical Physics

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We experimentally study two-body Coulomb explosions of CO2, O2, and CH3Cl molecules in intense femtosecond laser pulses. We observe an obvious variation in the ionic angular distribution of the fragments with respect to the kinetic energy releases (KERs). Using a classical model based on ab initio potential energy curves, we find that the dependence of the ionic angular distribution on the KER is relevant to the fact that the accurate potential energy deviates significantly from the value determined by applying the Coulomb interaction approximation at a relatively small internuclear distance of the molecule. We show that the KER-dependent ionic angular distribution provides an effective way to determine the critical internuclear distance at which the Coulomb interaction approximation holds or breaks down without relying on the knowledge of the accurate potential energy curves.

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Fragmentation dynamics of CH₃Cl^q+ (q = 2,3): theory and experiment

Abstract: A combined theoretical and experimental study of the dissociation of the di- and trication of the CH3Cl molecule has been performed. In addition to the obvious bond-breaking ionic fragments, the...

Cited by 3 publications

References 47 publications

Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

Probing Conical Intersection in the Multipathway Isomerization of CH₃Cl Using Coulomb Explosion

Energy-dependent photoion angular distributions in two-body Coulomb explosions of molecules

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Fragmentation dynamics of CH3Clq+ (q = 2,3): theory and experiment

Abstract: A combined theoretical and experimental study of the dissociation of the di- and trication of the CH3Cl molecule has been performed. In addition to the obvious bond-breaking ionic fragments, the...

Cited by 3 publications

References 47 publications

Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

Dynamic Effects on the Ionization-Induced Reactions of Methyl Halides: Quantum Mechanical and Molecular Dynamics Studies

Probing Conical Intersection in the Multipathway Isomerization of CH3Cl Using Coulomb Explosion

Energy-dependent photoion angular distributions in two-body Coulomb explosions of molecules

Contact Info

Product

Resources

About

Fragmentation dynamics of CH₃Cl^q+ (q = 2,3): theory and experiment

Probing Conical Intersection in the Multipathway Isomerization of CH₃Cl Using Coulomb Explosion