Modeling the coincident three-ion momentum imaging of diiodomethane photodissociation on reduced-dimensional potential energy surfaces
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866910032223797248 |
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| author | Ding, Yijue |
| author_facet | Ding, Yijue |
| contents | We present an efficient theoretical model to simulate observables in the time-resolved coincident three-ion Coulomb explosion experiment of diiodomethane. The model employs two degrees of freedom to describe the C-I bond breaking and the $\text{CH}_2\text{I}$ rotation during photodissociation, and three degrees of freedom to describe the coincident $\text{CH}_2^{+} + \text{I}^{2+} + \text{I}^{2+}$ fragmentation during the subsequent Coulomb explosion. By solving the equations of motion, the photodissociation pathways are obtained on two-dimensional potential energy surfaces of the valence excited states of the neutral molecule, and the asymptotic momenta of the three ionic fragments are determined on the three-dimensional ground-state potential energy surface of the fivefold-charged cation. The photodissociation pathways are consistent with previous \textit{ab initio} molecular dynamics simulations and indicate a $\text{CH}_2\text{I}$ rotational period of approximately 340 fs. The theoretical time-resolved kinetic energy release and the correlation between the kinetic energy release and the angle between the two $\text{I}^{2+}$ momenta show good agreement with experimental signals in part, reflecting and confirming the static $\text{CH}_2\text{I}_2$ state and the $\text{CH}_2\text{I} + \text{I}$ dissociation channels. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2507_14611 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Modeling the coincident three-ion momentum imaging of diiodomethane photodissociation on reduced-dimensional potential energy surfaces Ding, Yijue Chemical Physics We present an efficient theoretical model to simulate observables in the time-resolved coincident three-ion Coulomb explosion experiment of diiodomethane. The model employs two degrees of freedom to describe the C-I bond breaking and the $\text{CH}_2\text{I}$ rotation during photodissociation, and three degrees of freedom to describe the coincident $\text{CH}_2^{+} + \text{I}^{2+} + \text{I}^{2+}$ fragmentation during the subsequent Coulomb explosion. By solving the equations of motion, the photodissociation pathways are obtained on two-dimensional potential energy surfaces of the valence excited states of the neutral molecule, and the asymptotic momenta of the three ionic fragments are determined on the three-dimensional ground-state potential energy surface of the fivefold-charged cation. The photodissociation pathways are consistent with previous \textit{ab initio} molecular dynamics simulations and indicate a $\text{CH}_2\text{I}$ rotational period of approximately 340 fs. The theoretical time-resolved kinetic energy release and the correlation between the kinetic energy release and the angle between the two $\text{I}^{2+}$ momenta show good agreement with experimental signals in part, reflecting and confirming the static $\text{CH}_2\text{I}_2$ state and the $\text{CH}_2\text{I} + \text{I}$ dissociation channels. |
| title | Modeling the coincident three-ion momentum imaging of diiodomethane photodissociation on reduced-dimensional potential energy surfaces |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2507.14611 |