Prediction Through Quantum Dynamics Simulations: Photo-excited Cyclobutanone
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866916126512906240 |
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| author | Bennett, Olivia Freibert, Antonia Spinlove, K. Eryn Worth, Graham A. |
| author_facet | Bennett, Olivia Freibert, Antonia Spinlove, K. Eryn Worth, Graham A. |
| contents | Quantum dynamics simulations are becoming a standard tool for simulating photo-excited molecular systems involving a manifold of coupled states, known as non-adiabatic dynamics. While these simulations have had many successes in explaining experiments and giving details of non-adiabatic transitions, the question remains as to their predictive power. In this work, we present a set of quantum dynamics simulations on cyclobutanone, using both grid-based multi-configuration time-dependent Hartree (MCTDH) and direct dynamics variational multi-configuration Gaussian (DD-vMCG) methods. The former used a parameterised vibronic coupling model Hamiltonian and the latter generated the potential energy surfaces on-the-fly. The results give a picture of the non-adiabatic behaviour of this molecule and were used to calculate the signal from a gas-phase ultrafast electron diffraction (GUED) experiment. Corresponding experimental results will be obtained and presented at a later stage for comparison to test the predictive power of the methods. The results show that over the first 500 fs after photo-excitation to the S$_2$ state, cyclobutanone relaxes quickly to the S$_1$ state, but only a small population relaxes further to the S$_0$ state. No significant transfer of population to the triplet manifold is found. It is predicted that the GUED experiments over this time scale will see s signal related mostly to the C-O stretch motion and elongation of the molecular ring along the C-C-O axis. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_09933 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Prediction Through Quantum Dynamics Simulations: Photo-excited Cyclobutanone Bennett, Olivia Freibert, Antonia Spinlove, K. Eryn Worth, Graham A. Chemical Physics Quantum dynamics simulations are becoming a standard tool for simulating photo-excited molecular systems involving a manifold of coupled states, known as non-adiabatic dynamics. While these simulations have had many successes in explaining experiments and giving details of non-adiabatic transitions, the question remains as to their predictive power. In this work, we present a set of quantum dynamics simulations on cyclobutanone, using both grid-based multi-configuration time-dependent Hartree (MCTDH) and direct dynamics variational multi-configuration Gaussian (DD-vMCG) methods. The former used a parameterised vibronic coupling model Hamiltonian and the latter generated the potential energy surfaces on-the-fly. The results give a picture of the non-adiabatic behaviour of this molecule and were used to calculate the signal from a gas-phase ultrafast electron diffraction (GUED) experiment. Corresponding experimental results will be obtained and presented at a later stage for comparison to test the predictive power of the methods. The results show that over the first 500 fs after photo-excitation to the S$_2$ state, cyclobutanone relaxes quickly to the S$_1$ state, but only a small population relaxes further to the S$_0$ state. No significant transfer of population to the triplet manifold is found. It is predicted that the GUED experiments over this time scale will see s signal related mostly to the C-O stretch motion and elongation of the molecular ring along the C-C-O axis. |
| title | Prediction Through Quantum Dynamics Simulations: Photo-excited Cyclobutanone |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2402.09933 |