1
|
A Feshbach resonance in collisions between triplet ground-state molecules. Nature 2023; 614:54-58. [PMID: 36725997 DOI: 10.1038/s41586-022-05635-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 12/06/2022] [Indexed: 02/03/2023]
Abstract
Collisional resonances are important tools that have been used to modify interactions in ultracold gases, for realizing previously unknown Hamiltonians in quantum simulations1, for creating molecules from atomic gases2 and for controlling chemical reactions. So far, such resonances have been observed for atom-atom collisions, atom-molecule collisions3-7 and collisions between Feshbach molecules, which are very weakly bound8-10. Whether such resonances exist for ultracold ground-state molecules has been debated owing to the possibly high density of states and/or rapid decay of the resonant complex11-15. Here we report a very pronounced and narrow (25 mG) Feshbach resonance in collisions between two triplet ground-state NaLi molecules. This molecular Feshbach resonance has two special characteristics. First, the collisional loss rate is enhanced by more than two orders of magnitude above the background loss rate, which is saturated at the p-wave universal value, owing to strong chemical reactivity. Second, the resonance is located at a magnetic field where two open channels become nearly degenerate. This implies that the intermediate complex predominantly decays to the second open channel. We describe the resonant loss feature using a model with coupled modes that is analogous to a Fabry-Pérot cavity. Our observations provide strong evidence for the existence of long-lived coherent intermediate complexes even in systems without reaction barriers and open up the possibility of coherent control of chemical reactions.
Collapse
|
2
|
Yang H, Li Z, Zhang S, Bohn JL, Cao L, Zhang S, Wang G, Xu H, Li Z. Channel Selection of Ultracold Atom-Molecule Scattering in Dynamic Magnetic Fields. PHYSICAL REVIEW LETTERS 2022; 129:013402. [PMID: 35841560 DOI: 10.1103/physrevlett.129.013402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/02/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate that final states of ultracold molecules by scattering with atoms can be selectively produced using dynamic magnetic fields of multiple frequencies. We develop a multifrequency Floquet coupled channel method to study the channel selection by dynamic magnetic field control, which can be interpreted by a generalized quantum Zeno effect for the selected scattering channels. In particular, we use an atom-molecule spin-flip scattering to show that the transition to certain final states of the molecules in the inelastic scattering can be suppressed by engineered coupling between the Floquet states.
Collapse
Affiliation(s)
- Hanwei Yang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Zunqi Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Songbin Zhang
- Department of Physics, Shaanxi Normal University, Xi'an 710119, China
| | - John L Bohn
- JILA, University of Colorado, Boulder, Colorado 80309, USA
| | - Lushuai Cao
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shutao Zhang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Gaoren Wang
- School of Physics, Dalian University of Technology, Dalian 116024, China
| | - Haitan Xu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Zheng Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, China
| |
Collapse
|
3
|
Yang H, Wang XY, Su Z, Cao J, Zhang DC, Rui J, Zhao B, Bai CL, Pan JW. Evidence for the association of triatomic molecules in ultracold 23Na 40K + 40K mixtures. Nature 2022; 602:229-233. [PMID: 35140383 DOI: 10.1038/s41586-021-04297-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 11/29/2021] [Indexed: 11/09/2022]
Abstract
Ultracold assembly of diatomic molecules has enabled great advances in controlled chemistry, ultracold chemical physics and quantum simulation with molecules1-3. Extending the ultracold association to triatomic molecules will offer many new research opportunities and challenges in these fields. A possible approach is to form triatomic molecules in a mixture of ultracold atoms and diatomic molecules by using a Feshbach resonance between them4,5. Although ultracold atom-diatomic-molecule Feshbach resonances have been observed recently6,7, using these resonances to form triatomic molecules remains challenging. Here we report on evidence of the association of triatomic molecules near the Feshbach resonance between 23Na40K molecules in the rovibrational ground state and 40K atoms. We apply a radio-frequency pulse to drive the free-bound transition in ultracold mixtures of 23Na40K and 40K and monitor the loss of 23Na40K molecules. The association of triatomic molecules manifests itself as an additional loss feature in the radio-frequency spectra, which can be distinguished from the atomic loss feature. The observation that the distance between the association feature and the atomic transition changes with the magnetic field provides strong evidence for the formation of triatomic molecules. The binding energy of the triatomic molecules is estimated from the measurements. Our work contributes to the understanding of the complex ultracold atom-molecule Feshbach resonances and may open up an avenue towards the preparation and control of ultracold triatomic molecules.
Collapse
Affiliation(s)
- Huan Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Xin-Yao Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhen Su
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Jin Cao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - De-Chao Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Jun Rui
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Bo Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China. .,Shanghai Research Center for Quantum Sciences, Shanghai, China.
| | - Chun-Li Bai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China.
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China. .,Shanghai Research Center for Quantum Sciences, Shanghai, China.
| |
Collapse
|
4
|
Koyu S, Hermsmeier R, Tscherbul TV. Total angular momentum representation for state-to-state quantum scattering of cold molecules in a magnetic field. J Chem Phys 2022; 156:034112. [DOI: 10.1063/5.0074844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Suyesh Koyu
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | | | | |
Collapse
|
5
|
Hermsmeier R, Kłos J, Kotochigova S, Tscherbul TV. Quantum Spin State Selectivity and Magnetic Tuning of Ultracold Chemical Reactions of Triplet Alkali-Metal Dimers with Alkali-Metal Atoms. PHYSICAL REVIEW LETTERS 2021; 127:103402. [PMID: 34533330 DOI: 10.1103/physrevlett.127.103402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 06/29/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate that it is possible to efficiently control ultracold chemical reactions of alkali-metal atoms colliding with open-shell alkali-metal dimers in their metastable triplet states by choosing the internal hyperfine and rovibrational states of the reactants as well as by inducing magnetic Feshbach resonances with an external magnetic field. We base these conclusions on coupled-channel statistical calculations that include the effects of hyperfine contact and magnetic-field-induced Zeeman interactions on ultracold chemical reactions of hyperfine-resolved ground-state Na and the triplet NaLi(a^{3}Σ^{+}) producing singlet Na_{2}(^{1}Σ_{g}^{+}) and a Li atom. We find that the reaction rates are sensitive to the initial hyperfine states of the reactants. The chemical reaction of fully spin-polarized, high-spin states of rotationless NaLi(a^{3}Σ^{+},v=0,N=0) molecules with fully spin-polarized Na is suppressed by a factor of 10-100 compared to that of unpolarized reactants. We interpret these findings within the adiabatic state model, which treats the reaction as a sequence of nonadiabatic transitions between the initial nonreactive high-spin state and the final low-spin states of the reaction complex. In addition, we show that magnetic Feshbach resonances can similarly change reaction rate coefficients by several orders of magnitude. Some of these resonances are due to resonant trimer bound states dissociating to the N=2 rotational state of NaLi(a^{3}Σ^{+},v=0) and would thus exist in systems without hyperfine interactions.
Collapse
Affiliation(s)
| | - Jacek Kłos
- Department of Physics, Joint Quantum Institute, University of Maryland College Park, College Park, Maryland 20742, USA
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | | | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| |
Collapse
|
6
|
Collisional cooling of ultracold molecules. Nature 2020; 580:197-200. [DOI: 10.1038/s41586-020-2141-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 01/27/2020] [Indexed: 11/09/2022]
|
7
|
Morita M, Tscherbul TV. Restricted basis set coupled-channel calculations on atom-molecule collisions in magnetic fields. J Chem Phys 2019; 150:074110. [PMID: 30795668 DOI: 10.1063/1.5047063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Rigorous coupled-channel quantum scattering calculations on molecular collisions in external fields are computationally demanding due to the need to account for a large number of coupled channels and multiple total angular momenta J of the collision complex. We show that by restricting the total angular momentum basis to include only the states with helicities K ≤ Kmax, it is possible to obtain accurate elastic and inelastic cross sections for low-temperature He + CaH, Li + CaH, and Li + SrOH collisions in the presence of an external magnetic field at a small fraction of the computational cost of the full coupled-channel calculations (where K is the projection of the molecular rotational angular momentum on the atom-diatom axis). The optimal size of the truncated helicity basis set depends on the mechanism of the inelastic process and on the magnitude of the external magnetic field, with the minimal basis set (Kmax = 0) producing quantitatively accurate results for, e.g., ultracold Li + CaH and Li + SrOH scattering at low magnetic fields, leading to nearly 90-fold gain in computational efficiency. Larger basis sets are required to accurately describe the resonance structure in the magnetic field dependence of Li + CaH and Li + SrOH inelastic cross sections in the few partial wave-regime as well as indirect spin relaxation in He + CaH collisions. Our calculations indicate that the resonance structure is due to an interplay of the spin-rotation and Coriolis couplings between the basis states of different K and the couplings between the rotational states of the same K induced by the anisotropy of the interaction potential.
Collapse
Affiliation(s)
- Masato Morita
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| |
Collapse
|
8
|
McDonald M, Majewska I, Lee CH, Kondov SS, McGuyer BH, Moszynski R, Zelevinsky T. Control of Ultracold Photodissociation with Magnetic Fields. PHYSICAL REVIEW LETTERS 2018; 120:033201. [PMID: 29400515 DOI: 10.1103/physrevlett.120.033201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Indexed: 06/07/2023]
Abstract
Photodissociation of a molecule produces a spatial distribution of photofragments determined by the molecular structure and the characteristics of the dissociating light. Performing this basic reaction at ultracold temperatures allows its quantum mechanical features to dominate. In this regime, weak applied fields can be used to control the reaction. Here, we photodissociate ultracold diatomic strontium in magnetic fields below 10 G and observe striking changes in photofragment angular distributions. The observations are in excellent agreement with a multichannel quantum chemistry model that includes nonadiabatic effects and predicts strong mixing of partial waves in the photofragment energy continuum. The experiment is enabled by precise quantum-state control of the molecules.
Collapse
Affiliation(s)
- M McDonald
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - I Majewska
- Quantum Chemistry Laboratory, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - C-H Lee
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - S S Kondov
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - B H McGuyer
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - R Moszynski
- Quantum Chemistry Laboratory, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - T Zelevinsky
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| |
Collapse
|
9
|
Vieira D, Krems RV, Tscherbul TV. Molecular collisions and reactive scattering in external fields: Are field-induced couplings important at short range? J Chem Phys 2017; 146:024102. [PMID: 28088162 DOI: 10.1063/1.4973431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use accurate quantum scattering calculations to elucidate the role of short-range molecule-field interactions in atom-molecule inelastic collisions and abstraction chemical reactions at low temperatures. We consider two examples: elastic and inelastic scattering of NH(Σ3) molecules with Mg(S1) atoms in a magnetic field; reactive scattering LiF + H → Li + HF in an electric field. Our calculations suggest that, for non-reactive collision systems and abstraction chemical reactions, the molecule-field interactions cannot generally be neglected at short range because the atom-molecule potential passes through zero at short range. An important exception occurs for Zeeman transitions in atom-molecule collisions at magnetic fields ≲1000 G, for which the molecule-field couplings need only be included at large ρ outside the range of the atom-molecule interaction. Our results highlight the importance of an accurate description of ρ-dependent molecule-field interactions in quantum scattering calculations on molecular collisions and chemical reactions at low temperatures.
Collapse
Affiliation(s)
- D Vieira
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - R V Krems
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - T V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| |
Collapse
|
10
|
Kłos J, Hapka M, Chałasiński G, Halvick P, Stoecklin T. Theoretical study of the buffer-gas cooling and trapping of CrH(X6Σ+) by3He atoms. J Chem Phys 2016; 145:214305. [DOI: 10.1063/1.4968529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, USA
| | - Michał Hapka
- Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw, Poland
| | - Grzegorz Chałasiński
- Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw, Poland
| | - Philippe Halvick
- Institut des Sciences Moléculaires, Université de Bordeaux, CNRS-UMR 5255, 33405 Talence, France
| | - Thierry Stoecklin
- Institut des Sciences Moléculaires, Université de Bordeaux, CNRS-UMR 5255, 33405 Talence, France
| |
Collapse
|
11
|
Balakrishnan N. Perspective: Ultracold molecules and the dawn of cold controlled chemistry. J Chem Phys 2016; 145:150901. [DOI: 10.1063/1.4964096] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- N. Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| |
Collapse
|
12
|
Pawlak M, Shagam Y, Narevicius E, Moiseyev N. Adiabatic theory for anisotropic cold molecule collisions. J Chem Phys 2015; 143:074114. [PMID: 26298122 DOI: 10.1063/1.4928690] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mariusz Pawlak
- Schulich Faculty of Chemistry, Technion–Israel Institute of Technology, Haifa 32000, Israel
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Yuval Shagam
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Edvardas Narevicius
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nimrod Moiseyev
- Schulich Faculty of Chemistry, Technion–Israel Institute of Technology, Haifa 32000, Israel
- Faculty of Physics, Technion–Israel Institute of Technology, Haifa 32000, Israel
| |
Collapse
|
13
|
González-Martínez ML, Hutson JM. Ultracold hydrogen atoms: a versatile coolant to produce ultracold molecules. PHYSICAL REVIEW LETTERS 2013; 111:203004. [PMID: 24289682 DOI: 10.1103/physrevlett.111.203004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Indexed: 06/02/2023]
Abstract
We show theoretically that ultracold hydrogen atoms have very favorable properties for sympathetic cooling of molecules to microkelvin temperatures. We calculate the potential energy surfaces for spin-polarized interactions of H atoms with the prototype molecules NH(3Σ-) and OH(2Π) and show that they are shallow (50 to 80 cm(-1)) and only weakly anisotropic. We carry out quantum collision calculations on H+NH and H+OH and show that the ratio of elastic to inelastic cross sections is high enough to allow sympathetic cooling from temperatures well over 1 K for NH and around 250 mK for OH.
Collapse
Affiliation(s)
- Maykel L González-Martínez
- Joint Quantum Centre (JQC) Durham/Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | | |
Collapse
|
14
|
Affiliation(s)
- Mikhail Lemeshko
- a ITAMP, Harvard-Smithsonian Center for Astrophysics , Cambridge , MA , 02138 , USA
- b Physics Department , Harvard University , Cambridge , MA , 02138 , USA
- c Kavli Institute for Theoretical Physics , University of California , Santa Barbara , CA , 93106 , USA
| | - Roman V. Krems
- c Kavli Institute for Theoretical Physics , University of California , Santa Barbara , CA , 93106 , USA
- d Department of Chemistry , University of British Columbia , BC V6T 1Z1, Vancouver , Canada
| | - John M. Doyle
- b Physics Department , Harvard University , Cambridge , MA , 02138 , USA
| | - Sabre Kais
- e Departments of Chemistry and Physics , Purdue University , West Lafayette , IN , 47907 , USA
| |
Collapse
|
15
|
Singh V, Hardman KS, Lu MJ, Ellis A, Morrison MJ, Weinstein JD. Inelastic collisions of CaH with He at cryogenic temperatures. Mol Phys 2013. [DOI: 10.1080/00268976.2013.772668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Vijay Singh
- a Department of Physics , University of Nevada , Reno , USA
| | | | - Mei-Ju Lu
- a Department of Physics , University of Nevada , Reno , USA
| | - Aja Ellis
- a Department of Physics , University of Nevada , Reno , USA
| | | | | |
Collapse
|
16
|
Janssen LMC, van der Avoird A, Groenenboom GC. Quantum reactive scattering of ultracold NH(X (3)Σ(-)) radicals in a magnetic trap. PHYSICAL REVIEW LETTERS 2013; 110:063201. [PMID: 23432241 DOI: 10.1103/physrevlett.110.063201] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Indexed: 06/01/2023]
Abstract
We investigate the ultracold reaction dynamics of magnetically trapped NH(X (3)Σ(-)) radicals using rigorous quantum scattering calculations involving three coupled potential energy surfaces. We find that the reactive NH+NH cross section is driven by a short-ranged collisional mechanism, and its magnitude is only weakly dependent on magnetic field strength. Unlike most ultracold reactions observed so far, the NH+NH scattering dynamics is nonuniversal. Our results indicate that chemical reactions can cause more trap loss than spin-inelastic NH+NH collisions, making molecular evaporative cooling more difficult than previously anticipated.
Collapse
Affiliation(s)
- Liesbeth M C Janssen
- Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | | | | |
Collapse
|
17
|
Tscherbul TV, Grinev TA, Yu HG, Dalgarno A, Kłos J, Alexander MH. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: An ab initio study of He + CH 2(X̃) collisions. J Chem Phys 2012; 137:104302. [DOI: 10.1063/1.4748258] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
18
|
Suleimanov YV, Tscherbul TV, Krems RV. Efficient method for quantum calculations of molecule-molecule scattering properties in a magnetic field. J Chem Phys 2012; 137:024103. [DOI: 10.1063/1.4733288] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
19
|
Abstract
Characteristic parameters (energetic positions, widths, etc.) of the 23 spectroscopically observed (or potentially observable) quasi-bound energy levels for the ground state H(2) molecule are determined with high accuracy. The recent advances concerning nonadiabatic, relativistic, and quantum electrodynamical corrections have been taken into consideration. Theoretical approach is based on the careful investigation of the energy dependences of the real stationary scattering-state wave functions (their phase shifts and amplitudes). These energy dependences can be very accurately fitted to simple analytic formulas resulting from the quantum scattering theory. General criteria for the assignment of quasi-bound states are discussed and a new criterion is proposed, which excludes too broad and ambiguous resonances. To implement the proposed approach, a special high-precision computational method was used, which is described in full detail.
Collapse
Affiliation(s)
- Matti Selg
- Institute of Physics, University of Tartu, Riia 142, 51014 Tartu, Estonia
| |
Collapse
|
20
|
Feng E, Shao X, Yu C, Sun C, Huang W. Low energy collisions of CN(X 2Σ+) with He in magnetic fields. J Chem Phys 2012; 136:054302. [DOI: 10.1063/1.3679869] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Eryin Feng
- Department of Physics, Anhui normal university, Wuhu 241000, People's Republic of China
| | - Xi Shao
- Department of Physics, Anhui normal university, Wuhu 241000, People's Republic of China
| | - Chunhua Yu
- Department of Physics, Anhui normal university, Wuhu 241000, People's Republic of China
| | - Chunyan Sun
- Department of Physics, Anhui normal university, Wuhu 241000, People's Republic of China
| | - Wuying Huang
- Department of Physics, Anhui normal university, Wuhu 241000, People's Republic of China
| |
Collapse
|
21
|
Tscherbul TV, Sayfutyarova ER, Buchachenko AA, Dalgarno A. He–ThO(1Σ+) interactions at low temperatures: Elastic and inelastic collisions, transport properties, and complex formation in cold4He gas. J Chem Phys 2011; 134:144301. [DOI: 10.1063/1.3575399] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Pérez-Ríos J, Campos-Martínez J, Hernández MI. Ultracold O2 + O2 collisions in a magnetic field: On the role of the potential energy surface. J Chem Phys 2011; 134:124310. [DOI: 10.1063/1.3573968] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
23
|
Hummon MT, Tscherbul TV, Kłos J, Lu HI, Tsikata E, Campbell WC, Dalgarno A, Doyle JM. Cold N+NH collisions in a magnetic trap. PHYSICAL REVIEW LETTERS 2011; 106:053201. [PMID: 21405394 DOI: 10.1103/physrevlett.106.053201] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Indexed: 05/30/2023]
Abstract
We present an experimental and theoretical study of atom-molecule collisions in a mixture of cold, trapped N atoms and NH molecules at a temperature of ∼600 mK. We measure a small N+NH trap loss rate coefficient of k(loss)(N+NH)=9(5)(3)×10(-13) cm(3) s(-1). Accurate quantum scattering calculations based on ab initio interaction potentials are in agreement with experiment and indicate the magnetic dipole interaction to be the dominant loss mechanism. Our theory further indicates the ratio of N+NH elastic-to-inelastic collisions remains large (>100) into the mK regime.
Collapse
Affiliation(s)
- Matthew T Hummon
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Suleimanov YV, Krems RV. Efficient numerical method for locating Feshbach resonances of ultracold molecules in external fields. J Chem Phys 2011. [DOI: 10.1063/1.3512627] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
25
|
Stoecklin T, Halvick P. Collisional relaxation of MnH (X7Σ+) in a magnetic field: effect of the nuclear spin of Mn. Phys Chem Chem Phys 2011; 13:19142-7. [DOI: 10.1039/c1cp21466g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
26
|
Żuchowski PS, Hutson JM. Cold collisions of N (4S) atoms and NH (3Σ) molecules in magnetic fields. Phys Chem Chem Phys 2011; 13:3669-80. [DOI: 10.1039/c0cp01447h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
27
|
Tscherbul TV, Dalgarno A. Quantum theory of molecular collisions in a magnetic field: Efficient calculations based on the total angular momentum representation. J Chem Phys 2010; 133:184104. [DOI: 10.1063/1.3503500] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
28
|
Turpin F, Halvick P, Stoecklin T. The interaction of MnH(X Σ7+) with He:Ab initiopotential energy surface and bound states. J Chem Phys 2010; 132:214305. [DOI: 10.1063/1.3432762] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
29
|
Wallis AOG, Hutson JM. Production of ultracold NH molecules by sympathetic cooling with Mg. PHYSICAL REVIEW LETTERS 2009; 103:183201. [PMID: 19905803 DOI: 10.1103/physrevlett.103.183201] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Indexed: 05/28/2023]
Abstract
We show that sympathetic cooling of NH molecules by Mg atoms has a good prospect of success. We carry out calculations on M-changing collisions of NH (3Sigma-) molecules in magnetically trappable states with Mg, using a recently calculated potential energy surface. We show that elastic collision rates are much faster than inelastic rates for a wide range of fields at temperatures up to 10 mK and that the ratio increases for lower temperatures and magnetic fields.
Collapse
Affiliation(s)
- Alisdair O G Wallis
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
| | | |
Collapse
|
30
|
Lemeshko M, Friedrich B. Model Analysis of Rotationally Inelastic Ar + H2O Scattering in an Electric Field. J Phys Chem A 2009; 113:15055-63. [DOI: 10.1021/jp9051598] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mikhail Lemeshko
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Bretislav Friedrich
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| |
Collapse
|
31
|
Pérez-Ríos J, Bartolomei M, Campos-Martínez J, Hernández MI, Hernández-Lamoneda R. Quantum-Mechanical Study of the Collision Dynamics of O2(3Σg−) + O2(3Σg−) on a New ab Initio Potential Energy Surface. J Phys Chem A 2009; 113:14952-60. [DOI: 10.1021/jp905045b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jesús Pérez-Ríos
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain, and Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, 62210 Cuernavaca, Mor. México
| | - Massimiliano Bartolomei
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain, and Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, 62210 Cuernavaca, Mor. México
| | - José Campos-Martínez
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain, and Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, 62210 Cuernavaca, Mor. México
| | - Marta I. Hernández
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain, and Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, 62210 Cuernavaca, Mor. México
| | - Ramón Hernández-Lamoneda
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain, and Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, 62210 Cuernavaca, Mor. México
| |
Collapse
|
32
|
Pavlovic Z, Tscherbul TV, Sadeghpour HR, Groenenboom GC, Dalgarno A. Cold Collisions of OH(2Π) Molecules with He Atoms in External Fields. J Phys Chem A 2009; 113:14670-80. [DOI: 10.1021/jp904512r] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Z. Pavlovic
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, Department of Physics, University of Connecticut, Storrs, Connecticut 06269, Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, and Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - T. V. Tscherbul
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, Department of Physics, University of Connecticut, Storrs, Connecticut 06269, Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, and Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - H. R. Sadeghpour
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, Department of Physics, University of Connecticut, Storrs, Connecticut 06269, Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, and Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - G. C. Groenenboom
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, Department of Physics, University of Connecticut, Storrs, Connecticut 06269, Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, and Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - A. Dalgarno
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, Department of Physics, University of Connecticut, Storrs, Connecticut 06269, Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, and Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| |
Collapse
|
33
|
Campbell WC, Tscherbul TV, Lu HI, Tsikata E, Krems RV, Doyle JM. Mechanism of collisional spin relaxation in 3sigma molecules. PHYSICAL REVIEW LETTERS 2009; 102:013003. [PMID: 19257187 DOI: 10.1103/physrevlett.102.013003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Indexed: 05/27/2023]
Abstract
We measure and theoretically determine the effect of molecular rotational splitting on Zeeman relaxation rates in collisions of cold 3Sigma molecules with helium atoms in a magnetic field. All four stable isotopomers of the imidogen (NH) molecule are magnetically trapped and studied in collisions with 3He and 4He. The 4He data support the predicted 1/B_{e};{2} dependence of the collision-induced Zeeman relaxation rate coefficient on the molecular rotational constant B_{e}. The measured 3He rate coefficients are much larger than the 4He coefficients, depend less strongly on B_{e}, and theoretical analysis indicates they are strongly affected by a shape resonance. The results demonstrate the influence of molecular structure on collisional energy transfer at low temperatures.
Collapse
Affiliation(s)
- Wesley C Campbell
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | | | | | | |
Collapse
|
34
|
Tscherbul TV, Groenenboom GC, Krems RV, Dalgarno A. Dynamics of OH(2Π)–He collisions in combined electric and magnetic fields. Faraday Discuss 2009; 142:127-41; discussion 221-55. [DOI: 10.1039/b819198k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
35
|
Tscherbul TV, Krems RV. Quantum theory of chemical reactions in the presence of electromagnetic fields. J Chem Phys 2008; 129:034112. [DOI: 10.1063/1.2954021] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
36
|
Lemeshko M, Friedrich B. An analytic model of rotationally inelastic collisions of polar molecules in electric fields. J Chem Phys 2008; 129:024301. [DOI: 10.1063/1.2948392] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
37
|
Tscherbul TV. Differential scattering of cold molecules in superimposed electric and magnetic fields. J Chem Phys 2008; 128:244305. [DOI: 10.1063/1.2943197] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
38
|
Chen J, Steimle TC. The permanent electric dipole moment of calcium monodeuteride. J Chem Phys 2008; 128:144312. [DOI: 10.1063/1.2899651] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
|
39
|
|
40
|
Abrahamsson E, Tscherbul TV, Krems RV. Inelastic collisions of cold polar molecules in nonparallel electric and magnetic fields. J Chem Phys 2007; 127:044302. [PMID: 17672685 DOI: 10.1063/1.2748770] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors present a detailed study of low-temperature collisions between CaD molecules and He atoms in superimposed electric and magnetic fields with arbitrary orientations. Electric fields do not interact with the electron spin of the molecules directly but modify their rotational structure and, consequently, the spin-rotation interactions. The authors examine molecular Stark and Zeeman energy levels as functions of the angle between the fields and show that rotating fields may induce and shift avoided crossings between the Zeeman levels of the rotationally ground and rotationally excited states of the molecule. The dynamics of molecular collisions are extremely sensitive to external fields near these avoided crossings and it is shown that molecular collisions may be controlled by varying both the strength and the relative orientation of the fields. The effects observed in this study are due to interactions of the isolated molecules with external fields so the conclusions should be relevant for collisions of molecules with other atoms or collisions of molecules with each other. This study demonstrates that electric fields may be used to enhance or suppress spin-rotation interactions in molecules. The spin-rotation interactions induce nonadiabatic couplings between states of different total spins in systems of two open-shell species and it is suggested that electric fields might be used for controlling nonadiabatic spin transitions and spin-forbidden chemical reactions of cold molecules in a magnetic trap.
Collapse
Affiliation(s)
- E Abrahamsson
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | | | | |
Collapse
|
41
|
Campbell WC, Tsikata E, Lu HI, van Buuren LD, Doyle JM. Magnetic trapping and Zeeman relaxation of NH (X3Sigma-). PHYSICAL REVIEW LETTERS 2007; 98:213001. [PMID: 17677770 DOI: 10.1103/physrevlett.98.213001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Indexed: 05/15/2023]
Abstract
NH radicals are magnetically trapped and their Zeeman relaxation and energy transport collision cross sections with helium are measured. Continuous buffer-gas loading of the trap is direct from a room-temperature molecular beam. The Zeeman relaxation (inelastic) cross section of magnetically trapped electronic, vibrational, and rotational ground state NH molecules in collisions with 3He is measured to be 3.8+/-1.1 x 10(-19) cm(2) at 710 mK. The NH-He energy transport cross section is also measured, indicating a ratio of diffusive to inelastic cross sections of gamma=7 x 10(4), in agreement with recent theory [R. V. Krems, H. R. Sadeghpour, A. Dalgarno, D. Zgid, J. Kłos, and G. Chałasiński, Phys. Rev. A 68, 051401 (2003)10.1103/PhysRevA.68.051401].
Collapse
Affiliation(s)
- Wesley C Campbell
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
| | | | | | | | | |
Collapse
|
42
|
Tscherbul TV, Krems RV. Manipulating spin-dependent interactions in rotationally excited cold molecules with electric fields. J Chem Phys 2006; 125:194311. [PMID: 17129107 DOI: 10.1063/1.2374896] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use rigorous quantum mechanical theory to study collisions of magnetically oriented cold molecules in the presence of superimposed electric and magnetic fields. It is shown that electric fields suppress the spin-rotation interaction in rotationally excited 2Sigma molecules and inhibit rotationally elastic and inelastic transitions accompanied by electron spin reorientation. We demonstrate that electric fields enhance collisional spin relaxation in 3Sigma molecules and discuss the mechanisms for electric field control of spin-changing transitions in collisions of rotationally excited CaD(2Sigma) and ND(3Sigma) molecules with helium atoms. The propensities for spin depolarization in the rotationally excited molecules are analyzed based on the calculations of collision rate constants at T=0.5 K.
Collapse
Affiliation(s)
- T V Tscherbul
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
| | | |
Collapse
|
43
|
Tscherbul TV, Krems RV. Controlling electronic spin relaxation of cold molecules with electric fields. PHYSICAL REVIEW LETTERS 2006; 97:083201. [PMID: 17026301 DOI: 10.1103/physrevlett.97.083201] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2006] [Indexed: 05/12/2023]
Abstract
We present a theoretical study of atom-molecule collisions in superimposed electric and magnetic fields and show that dynamics of electronic spin relaxation in molecules at temperatures below 0.5 K can be manipulated by varying the strength and the relative orientation of the applied fields. The mechanism of electric field control of Zeeman transitions is based on an intricate interplay between intramolecular spin-rotation couplings and molecule-field interactions. We suggest that electric fields may affect chemical reactions through inducing nonadiabatic spin transitions and facilitate evaporative cooling of molecules in a magnetic trap.
Collapse
Affiliation(s)
- T V Tscherbul
- Department of Chemistry, University of British Columbia, Vancouver, B.C. V6T 1Z1, Canada
| | | |
Collapse
|
44
|
Bodo E, Gianturco FA. Collisional quenching of molecular ro-vibrational energy by He buffer loading at ultralow energies. INT REV PHYS CHEM 2006. [DOI: 10.1080/01442350600772928] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
45
|
Krems RV. Controlling collisions of ultracold atoms with dc electric fields. PHYSICAL REVIEW LETTERS 2006; 96:123202. [PMID: 16605902 DOI: 10.1103/physrevlett.96.123202] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 03/12/2006] [Indexed: 05/08/2023]
Abstract
It is demonstrated that elastic collisions of ultracold atoms forming a heteronuclear collision complex can be manipulated by laboratory practicable dc electric fields. The mechanism of electric field control is based on the interaction of the instantaneous dipole moment of the collision pair with external electric fields. It is shown that this interaction is dramatically enhanced in the presence of a p-wave shape or Feshbach scattering resonance near the collision threshold, which leads to novel electric-field-induced Feshbach resonances.
Collapse
Affiliation(s)
- R V Krems
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
| |
Collapse
|
46
|
Korolkov MV, Weitzel KM. On the control of product yields in the photofragmentation of deuteriumchlorid ions (DCl+). J Chem Phys 2005; 123:164308. [PMID: 16268698 DOI: 10.1063/1.2076687] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The prospect of controlling the photofragmentation of deuterium chloride ions (DCl+) via strong ultrashort IR laser pulses has been investigated by a numerical solution of coupled Schrodinger equations. The calculations provide evidence that the ratio of product ion yields Cl+ versus D+ can be manipulated by an appropriate choice of laser pulse parameters, in particular, central laser frequency, pulse duration, intensity, and chirp. The analysis of time-dependent populations reveals competition between intra- and interelectronic state excitations, enabling the understanding of quantum control at the molecular level.
Collapse
Affiliation(s)
- Mikhail V Korolkov
- Stephanov Institute of Physics, National Academy of Science, Republic of Belarus and Philipps Universität Marburg, Fachbereich Chemie, Hans Meerwein Strasse, 35032 Marburg, Germany
| | | |
Collapse
|
47
|
Maussang K, Egorov D, Helton JS, Nguyen SV, Doyle JM. Zeeman relaxation of CaF in low-temperature collisions with helium. PHYSICAL REVIEW LETTERS 2005; 94:123002. [PMID: 15903915 DOI: 10.1103/physrevlett.94.123002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Indexed: 05/02/2023]
Abstract
The collision-induced Zeeman relaxation rate for collisions of CaF X2Sigma(v('')=0) with 3He is measured to be Gamma(Z)=(7.7+5.4/-2.5)x10(-15) cm(3)/s at 2 K. This rate is a direct measurement of the influence of spin-rotation coupling on Zeeman relaxation in the first rotational level of CaF. The relationship of this rate to known molecular constants is consistent with recent theory of cold molecular collisions and outlines the (2)Sigma molecules conducive to magnetic trapping.
Collapse
Affiliation(s)
- Kenneth Maussang
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | | | | |
Collapse
|
48
|
Cybulski H, Krems RV, Sadeghpour HR, Dalgarno A, Kłos J, Groenenboom GC, van der Avoird A, Zgid D, Chałasiński G. Interaction of NH(XΣ−3) with He: Potential energy surface, bound states, and collisional Zeeman relaxation. J Chem Phys 2005; 122:094307. [PMID: 15836128 DOI: 10.1063/1.1857473] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A detailed analysis of the He-NH((3)Sigma(-)) van der Waals complex is presented. We discuss ab initio calculations of the potential energy surface and fitting procedures with relevance to cold collisions, and we present accurate calculations of bound energy levels of the triatomic complex as well as collisional properties of NH molecules in a buffer gas of (3)He. The influence of the external magnetic field used to trap the NH molecules and the effect of the atom-molecule interaction potential on the collisionally induced Zeeman relaxation are explored. It is shown that minute variations of the interaction potential due to different fitting procedures may alter the Zeeman relaxation rate at ultralow temperatures by as much as 50%.
Collapse
Affiliation(s)
- H Cybulski
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warszawa, Poland
| | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Krems RV, Kłos J, Rode MF, Szcze Sniak MM, Chałasiński G, Dalgarno A. Suppression of angular forces in collisions of non-S-state transition metal atoms. PHYSICAL REVIEW LETTERS 2005; 94:013202. [PMID: 15698078 DOI: 10.1103/physrevlett.94.013202] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Indexed: 05/24/2023]
Abstract
Angular momentum transfer is expected to occur rapidly in collisions of atoms in states of nonzero angular momenta due to the large torque of angular forces. We show that despite the presence of internal angular momenta transition metal atoms interact in collisions with helium effectively as spherical atoms and angular momentum transfer is slow. Thus, magnetic trapping and sympathetic cooling of transition metal atoms to ultracold temperatures should be readily achievable. Our results open up new avenues of research with a broad class of ultracold atoms.
Collapse
Affiliation(s)
- R V Krems
- Harvard-MIT Center for Ultracold Atoms, Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | | | | | | | | | | |
Collapse
|
50
|
Krems RV. Molecules near absolute zero and external field control of atomic and molecular dynamics. INT REV PHYS CHEM 2005. [DOI: 10.1080/01442350500167161] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|