Quantum Chaos in the Dynamics of Molecules
Quantum chaos is reviewed from the viewpoint of “what is molecule?”, particularly placing emphasis on their dynamics. Molecules are composed of heavy nuclei and light electrons, and thereby the very basic molecular theory due to Born and Oppenheimer gives a view that quantum electronic states provid...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Entropy |
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| Online Access: | https://www.mdpi.com/1099-4300/25/1/63 |
| _version_ | 1797443035158544384 |
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| author | Kazuo Takatsuka |
| author_facet | Kazuo Takatsuka |
| author_sort | Kazuo Takatsuka |
| collection | DOAJ |
| description | Quantum chaos is reviewed from the viewpoint of “what is molecule?”, particularly placing emphasis on their dynamics. Molecules are composed of heavy nuclei and light electrons, and thereby the very basic molecular theory due to Born and Oppenheimer gives a view that quantum electronic states provide potential functions working on nuclei, which in turn are often treated classically or semiclassically. Therefore, the classic study of chaos in molecular science began with those nuclear dynamics particularly about the vibrational energy randomization within a molecule. Statistical laws in probabilities and rates of chemical reactions even for small molecules of several atoms are among the chemical phenomena requiring the notion of chaos. Particularly the dynamics behind unimolecular decomposition are referred to as Intra-molecular Vibrational energy Redistribution (IVR). Semiclassical mechanics is also one of the main research fields of quantum chaos. We herein demonstrate chaos that appears only in semiclassical and full quantum dynamics. A fundamental phenomenon possibly giving birth to quantum chaos is “bifurcation and merging” of quantum wavepackets, rather than “stretching and folding” of the baker’s transformation and the horseshoe map as a geometrical foundation of classical chaos. Such wavepacket bifurcation and merging are indeed experimentally measurable as we showed before in the series of studies on real-time probing of nonadiabatic chemical reactions. After tracking these aspects of molecular chaos, we will explore quantum chaos found in nonadiabatic electron wavepacket dynamics, which emerges in the realm far beyond the Born-Oppenheimer paradigm. In this class of chaos, we propose a notion of Intra-molecular Nonadiabatic Electronic Energy Redistribution (INEER), which is a consequence of the chaotic fluxes of electrons and energy within a molecule. |
| first_indexed | 2024-03-09T12:50:16Z |
| format | Article |
| id | doaj.art-b60c12985bf34d668c34c6dbf183dc34 |
| institution | Directory Open Access Journal |
| issn | 1099-4300 |
| language | English |
| last_indexed | 2024-03-09T12:50:16Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Entropy |
| spelling | doaj.art-b60c12985bf34d668c34c6dbf183dc342023-11-30T22:07:42ZengMDPI AGEntropy1099-43002022-12-012516310.3390/e25010063Quantum Chaos in the Dynamics of MoleculesKazuo Takatsuka0Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, JapanQuantum chaos is reviewed from the viewpoint of “what is molecule?”, particularly placing emphasis on their dynamics. Molecules are composed of heavy nuclei and light electrons, and thereby the very basic molecular theory due to Born and Oppenheimer gives a view that quantum electronic states provide potential functions working on nuclei, which in turn are often treated classically or semiclassically. Therefore, the classic study of chaos in molecular science began with those nuclear dynamics particularly about the vibrational energy randomization within a molecule. Statistical laws in probabilities and rates of chemical reactions even for small molecules of several atoms are among the chemical phenomena requiring the notion of chaos. Particularly the dynamics behind unimolecular decomposition are referred to as Intra-molecular Vibrational energy Redistribution (IVR). Semiclassical mechanics is also one of the main research fields of quantum chaos. We herein demonstrate chaos that appears only in semiclassical and full quantum dynamics. A fundamental phenomenon possibly giving birth to quantum chaos is “bifurcation and merging” of quantum wavepackets, rather than “stretching and folding” of the baker’s transformation and the horseshoe map as a geometrical foundation of classical chaos. Such wavepacket bifurcation and merging are indeed experimentally measurable as we showed before in the series of studies on real-time probing of nonadiabatic chemical reactions. After tracking these aspects of molecular chaos, we will explore quantum chaos found in nonadiabatic electron wavepacket dynamics, which emerges in the realm far beyond the Born-Oppenheimer paradigm. In this class of chaos, we propose a notion of Intra-molecular Nonadiabatic Electronic Energy Redistribution (INEER), which is a consequence of the chaotic fluxes of electrons and energy within a molecule.https://www.mdpi.com/1099-4300/25/1/63quantum chaoselectronic-state chaoselectron dynamicsnonadiabatic dynamicschemical dynamicssemiclassical mechanics |
| spellingShingle | Kazuo Takatsuka Quantum Chaos in the Dynamics of Molecules Entropy quantum chaos electronic-state chaos electron dynamics nonadiabatic dynamics chemical dynamics semiclassical mechanics |
| title | Quantum Chaos in the Dynamics of Molecules |
| title_full | Quantum Chaos in the Dynamics of Molecules |
| title_fullStr | Quantum Chaos in the Dynamics of Molecules |
| title_full_unstemmed | Quantum Chaos in the Dynamics of Molecules |
| title_short | Quantum Chaos in the Dynamics of Molecules |
| title_sort | quantum chaos in the dynamics of molecules |
| topic | quantum chaos electronic-state chaos electron dynamics nonadiabatic dynamics chemical dynamics semiclassical mechanics |
| url | https://www.mdpi.com/1099-4300/25/1/63 |
| work_keys_str_mv | AT kazuotakatsuka quantumchaosinthedynamicsofmolecules |