Mechanisms for supercollisions
The mechanism of collisional energy transfer in collisions between a highly excited polyatomic and a monatomic bath gas is investigated for benzene-rare-gas systems by carrying out both vibrational close-coupling, infinite-order sudden quantum-scattering computations and classical trajectory calcula...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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1995
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| _version_ | 1797099720412233728 |
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| author | Clary, D Gilbert, R Bernshtein, V Oref, I |
| author_facet | Clary, D Gilbert, R Bernshtein, V Oref, I |
| author_sort | Clary, D |
| collection | OXFORD |
| description | The mechanism of collisional energy transfer in collisions between a highly excited polyatomic and a monatomic bath gas is investigated for benzene-rare-gas systems by carrying out both vibrational close-coupling, infinite-order sudden quantum-scattering computations and classical trajectory calculations with a high degree of initial internal excitation; the quantum calculations involved up to two vibrational modes. It is found in the quantum-scattering calculations that if one of the vibrational modes is of low frequency (and particularly if it is an out-of-plane motion), then the cross-section for transferring large amounts of energy is particularly large, and involves multi-quantum transitions. Although the quantum simulations have far fewer modes (and hence involve a far lower density of states) than in an actual system, this suggests that low-frequency/out-of-plane modes are prominent in transferring significant amounts of energy (and perhaps in 'supercollisions'), since a microcanonical ensemble in an actual system at high internal energy will contain a large proportion of states with high excitation in low-frequency modes. Both the quantum and trajectory results are consistent with a supercollision mechanism which is a head-on collision between a bath-gas atom and a rapidly moving substrate atom involved in a large-amplitude motion such as occurs with a highly excited low-frequency out-of-plane vibration. |
| first_indexed | 2024-03-07T05:27:37Z |
| format | Journal article |
| id | oxford-uuid:e11c605a-4756-4a55-86a6-2224d21df6d2 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:27:37Z |
| publishDate | 1995 |
| record_format | dspace |
| spelling | oxford-uuid:e11c605a-4756-4a55-86a6-2224d21df6d22022-03-27T09:52:02ZMechanisms for supercollisionsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:e11c605a-4756-4a55-86a6-2224d21df6d2EnglishSymplectic Elements at Oxford1995Clary, DGilbert, RBernshtein, VOref, IThe mechanism of collisional energy transfer in collisions between a highly excited polyatomic and a monatomic bath gas is investigated for benzene-rare-gas systems by carrying out both vibrational close-coupling, infinite-order sudden quantum-scattering computations and classical trajectory calculations with a high degree of initial internal excitation; the quantum calculations involved up to two vibrational modes. It is found in the quantum-scattering calculations that if one of the vibrational modes is of low frequency (and particularly if it is an out-of-plane motion), then the cross-section for transferring large amounts of energy is particularly large, and involves multi-quantum transitions. Although the quantum simulations have far fewer modes (and hence involve a far lower density of states) than in an actual system, this suggests that low-frequency/out-of-plane modes are prominent in transferring significant amounts of energy (and perhaps in 'supercollisions'), since a microcanonical ensemble in an actual system at high internal energy will contain a large proportion of states with high excitation in low-frequency modes. Both the quantum and trajectory results are consistent with a supercollision mechanism which is a head-on collision between a bath-gas atom and a rapidly moving substrate atom involved in a large-amplitude motion such as occurs with a highly excited low-frequency out-of-plane vibration. |
| spellingShingle | Clary, D Gilbert, R Bernshtein, V Oref, I Mechanisms for supercollisions |
| title | Mechanisms for supercollisions |
| title_full | Mechanisms for supercollisions |
| title_fullStr | Mechanisms for supercollisions |
| title_full_unstemmed | Mechanisms for supercollisions |
| title_short | Mechanisms for supercollisions |
| title_sort | mechanisms for supercollisions |
| work_keys_str_mv | AT claryd mechanismsforsupercollisions AT gilbertr mechanismsforsupercollisions AT bernshteinv mechanismsforsupercollisions AT orefi mechanismsforsupercollisions |