Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems
The H^{+}+H and D^{+}+D collisions represent the simplest examples of collisions involving identical fermions and bosons, respectively. We report a study of these collisions in the range of energies corresponding to 0–40 K at a resolution of 100 mK based on a half-collision approach. Using the techn...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2018-09-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.8.031085 |
| _version_ | 1818981292646072320 |
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| author | Maximilian Beyer Frédéric Merkt |
| author_facet | Maximilian Beyer Frédéric Merkt |
| author_sort | Maximilian Beyer |
| collection | DOAJ |
| description | The H^{+}+H and D^{+}+D collisions represent the simplest examples of collisions involving identical fermions and bosons, respectively. We report a study of these collisions in the range of energies corresponding to 0–40 K at a resolution of 100 mK based on a half-collision approach. Using the technique of pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopy (PFI-ZEKE-PES), which relies on the pulsed field ionization of nonpenetrating Rydberg states of very high principal quantum number (n≥250), we have measured the positions and widths of all low-lying shape resonances of this collision and compare them with the results of ab initio calculations that consider nonadiabatic, relativistic, and radiative corrections to the Born-Oppenheimer energies. Excellent agreement between calculated and measured widths and positions is found except for the X^{+}(v^{+}=25,N^{+}=8) shape resonance, the width of which is calculated to be narrower than observed. Comparison with similar observations made for the H^{+}+H collision [Beyer and Merkt Phys. Rev. Lett. 116, 093001 (2016)PRLTAO0031-900710.1103/PhysRevLett.116.093001] indicates that the shape resonances measured by PFI-ZEKE-PES are broadened by the effects of the localization of the charge of the dissociating ion core arising from a nonadiabatic coupling between ion core and Rydberg electron. A simple model is presented that enables one to predict which shape resonances are likely to be affected and to correct for the resulting broadening. Two shape resonances of D_{2}^{+}, the X^{+}(v^{+}=26,N^{+}=5) and the A^{+}(v^{+}=0,N^{+}=5) resonances, have electric-dipole-allowed transitions to bound states of D_{2}^{+} and are shown to facilitate the radiative association at low temperature. The results are used to determine the elastic cross sections of the H^{+}+H and D^{+}+D collisions for partial waves up to N^{+}=11 and the radiative-association cross sections and rate constants in the range between 10 mK and 100 000 K. |
| first_indexed | 2024-12-20T17:29:00Z |
| format | Article |
| id | doaj.art-bad0f2acb9ad44898fff9323ce2618d4 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-20T17:29:00Z |
| publishDate | 2018-09-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-bad0f2acb9ad44898fff9323ce2618d42022-12-21T19:31:27ZengAmerican Physical SocietyPhysical Review X2160-33082018-09-018303108510.1103/PhysRevX.8.031085Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision SystemsMaximilian BeyerFrédéric MerktThe H^{+}+H and D^{+}+D collisions represent the simplest examples of collisions involving identical fermions and bosons, respectively. We report a study of these collisions in the range of energies corresponding to 0–40 K at a resolution of 100 mK based on a half-collision approach. Using the technique of pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopy (PFI-ZEKE-PES), which relies on the pulsed field ionization of nonpenetrating Rydberg states of very high principal quantum number (n≥250), we have measured the positions and widths of all low-lying shape resonances of this collision and compare them with the results of ab initio calculations that consider nonadiabatic, relativistic, and radiative corrections to the Born-Oppenheimer energies. Excellent agreement between calculated and measured widths and positions is found except for the X^{+}(v^{+}=25,N^{+}=8) shape resonance, the width of which is calculated to be narrower than observed. Comparison with similar observations made for the H^{+}+H collision [Beyer and Merkt Phys. Rev. Lett. 116, 093001 (2016)PRLTAO0031-900710.1103/PhysRevLett.116.093001] indicates that the shape resonances measured by PFI-ZEKE-PES are broadened by the effects of the localization of the charge of the dissociating ion core arising from a nonadiabatic coupling between ion core and Rydberg electron. A simple model is presented that enables one to predict which shape resonances are likely to be affected and to correct for the resulting broadening. Two shape resonances of D_{2}^{+}, the X^{+}(v^{+}=26,N^{+}=5) and the A^{+}(v^{+}=0,N^{+}=5) resonances, have electric-dipole-allowed transitions to bound states of D_{2}^{+} and are shown to facilitate the radiative association at low temperature. The results are used to determine the elastic cross sections of the H^{+}+H and D^{+}+D collisions for partial waves up to N^{+}=11 and the radiative-association cross sections and rate constants in the range between 10 mK and 100 000 K.http://doi.org/10.1103/PhysRevX.8.031085 |
| spellingShingle | Maximilian Beyer Frédéric Merkt Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems Physical Review X |
| title | Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems |
| title_full | Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems |
| title_fullStr | Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems |
| title_full_unstemmed | Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems |
| title_short | Half-Collision Approach to Cold Chemistry: Shape Resonances, Elastic Scattering, and Radiative Association in the H^{+}+H and D^{+}+D Collision Systems |
| title_sort | half collision approach to cold chemistry shape resonances elastic scattering and radiative association in the h h and d d collision systems |
| url | http://doi.org/10.1103/PhysRevX.8.031085 |
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