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Rayment MH, Hogan SD. Electrostatic Trapping of N_{2} Molecules in High Rydberg States. PHYSICAL REVIEW LETTERS 2024; 132:113201. [PMID: 38563928 DOI: 10.1103/physrevlett.132.113201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/12/2024] [Indexed: 04/04/2024]
Abstract
N_{2} molecules traveling in pulsed supersonic beams have been excited from their X ^{1}Σ_{g}^{+} ground electronic state to long-lived Rydberg states with principal quantum numbers between 39 and 48 using a resonance-enhanced two-color three-photon excitation scheme. The Rydberg states populated had static electric dipole moments exceeding 5000 D which allowed deceleration of the molecules to rest in the laboratory-fixed frame of reference and three-dimensional trapping using inhomogeneous electric fields. The trapped molecules were confined for up to 10 ms, with effective trap decay time constants increasing with principal quantum number, and ranging from 450 to 700 μs. These observations, and comparison with the results of similar measurements with He atoms, indicate that the decay dynamics of the trapped Rydberg N_{2} molecules are dominated by spontaneous emission and do not exhibit significant contributions from effects of intramolecular interactions that lead to non-radiative decay.
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Affiliation(s)
- M H Rayment
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - S D Hogan
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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Merkt F, Höveler K, Deiglmayr J. Reactions of H 2, HD, and D 2 with H 2+, HD +, and D 2+: Product-Channel Branching Ratios and Simple Models. J Phys Chem Lett 2022; 13:864-871. [PMID: 35045261 PMCID: PMC8802320 DOI: 10.1021/acs.jpclett.1c03374] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Abstract
We present measurements of the product-channel branching ratios of the reactions (i) HD+ + HD forming H2D+ + D (38.1(30)%) and HD2+ + H (61.9(30)%), (ii) HD+ + D2 forming HD2+ + D (61.4(35)%) and D3+ + H (38.6(35)%), and (iii) D2+ + HD forming HD2++ D (60.5(20)%) and D3+ + H (39.5(20)%) at collision energies Ecoll near zero, i.e., below kB × 1 K. These branching ratios are compared with branching ratios predicted using three simple models: a combinatorial model (M1), a model (M2) describing the reactions as H-, H+-, D-, and D+-transfer processes, and a statistical model (M3) that relates the reaction rate coefficients to the translational and rovibrational state densities of the HnD3-n+ + H/D (n = 0, 1, 2 or 3) product channels. The experimental data are incompatible with the predictions of models M1 and M2 and reveal that the branching ratios exhibit clear correlations with the product state densities.
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Affiliation(s)
- Frédéric Merkt
- Laboratorium für
Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - Katharina Höveler
- Laboratorium für
Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
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Rayment MH, Hogan SD. Quantum-state-dependent decay rates of electrostatically trapped Rydberg NO molecules. Phys Chem Chem Phys 2021; 23:18806-18822. [PMID: 34612419 PMCID: PMC8900602 DOI: 10.1039/d1cp01930a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitric oxide (NO) molecules travelling in pulsed supersonic beams have been prepared in long-lived Rydberg-Stark states by resonance-enhanced two-colour two-photon excitation from the X 2Π1/2 (v'' = 0, J'' = 3/2) ground state, through the A 2Σ+ (v' = 0, N' = 0, J' = 1/2) intermediate state. These excited molecules were decelerated from 795 ms-1 to rest in the laboratory-fixed frame of reference, in the travelling electric traps of a transmission-line Rydberg-Stark decelerator. The decelerator was operated at 30 K to minimise effects of blackbody radiation on the molecules during deceleration and trapping. The molecules were electrostatically trapped for times of up to 1 ms, and detected in situ by pulsed electric field ionisation. Measurements of the rate of decay from the trap were performed for states with principal quantum numbers between n = 32 and 50, in Rydberg series converging to the N+= 0, 1, and 2 rotational states of NO+. For the range of Rydberg states studied, the measured decay times of between 200 μs and 400 μs were generally observed to reduce as the value of n was increased. For some particular values of n deviations from this trend were seen. These observations are interpreted, with the aid of numerical calculations, to arise as a result of contributions to the decay rates, on the order of 1 kHz, from rotational and vibrational channel interactions. These results shed new light on the role of weak intramolecular interactions on the slow decay of long-lived Rydberg states in NO.
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Affiliation(s)
- M H Rayment
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
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Höveler K, Deiglmayr J, Merkt F. Deviation of the rate of the reaction from Langevin behaviour below 1 K, branching ratios for the and product channels, and product-kinetic-energy distributions. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1954708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Johannes Deiglmayr
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
- Department of Physics, University of Leipzig, Leipzig, Germany
| | - Frédéric Merkt
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
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Höveler K, Deiglmayr J, Agner JA, Schmutz H, Merkt F. The H 2+ + HD reaction at low collision energies: H 3+/H 2D + branching ratio and product-kinetic-energy distributions. Phys Chem Chem Phys 2021; 23:2676-2685. [PMID: 33480928 DOI: 10.1039/d0cp06107g] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fully state-selected reactions between H2+ molecules in the X+ 2Σg+(v+ = 0, N+ = 0) state and HD molecules in the X 1Σg+(v = 0, J = 0) state forming H3+ + D and H2D+ + H have been studied at collision energies Ecoll between 0 and kB·30 K with a resolution of about 75 mK at the lowest energies. H2 molecules in a supersonic beam were prepared in Rydberg-Stark states with principal quantum number n = 27 and merged with a supersonic beam of ground-state HD molecules using a curved surface-electrode Rydberg-Stark decelerator and deflector. The reaction between H2+ and HD was studied within the orbit of the Rydberg electron to avoid heating of the ions by stray electric fields. The reaction was observed for well-defined and adjustable time intervals, called reaction-observation windows, between two electric-field pulses. The first pulse swept all ions away from the reaction volume and its falling edge defined the beginning of the reaction-observation window. The second pulse extracted the product ions toward a charged-particle detector located at the end of a time-of-flight tube and its rising edge defined the end of the reaction-observation window. Monitoring and analysing the time-of-flight distributions of the H3+ and H2D+ products in dependence of the duration of the reaction-observation window enabled us to obtain information on the kinetic-energy distribution of the product ions and determine branching ratios of the H3+ + D and H2D+ + H reaction channels. The mean product-kinetic-energy release is 0.46(5) eV, representing 27(3)% of the available energy, and the H3+ + D product branching ratio is 0.225(20). The relative reaction rates correspond closely to Langevin capture rates down to the lowest energies probed experimentally (≈kB·50 mK).
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Affiliation(s)
- Katharina Höveler
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
| | - Johannes Deiglmayr
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
| | - Josef A Agner
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
| | - Hansjürg Schmutz
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
| | - Frédéric Merkt
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
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Deller A, Hogan SD. Excitation and characterization of long-lived hydrogenic Rydberg states of nitric oxide. J Chem Phys 2020; 152:144305. [PMID: 32295365 DOI: 10.1063/5.0003092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High Rydberg states of nitric oxide (NO) with principal quantum numbers between 40 and 100 and lifetimes in excess of 10 µs have been prepared by resonance enhanced two-color two-photon laser excitation from the X 2Π1/2 ground state through the A 2Σ+ intermediate state. Molecules in these long-lived Rydberg states were detected and characterized 126 µs after laser photoexcitation by state-selective pulsed electric field ionization. The laser excitation and electric field ionization data were combined to construct two-dimensional spectral maps. These maps were used to identify the rotational states of the NO+ ion core to which the observed series of long-lived hydrogenic Rydberg states converge. The results presented pave the way for Rydberg-Stark deceleration and electrostatic trapping experiments with NO, which are expected to shed further light on the decay dynamics of these long-lived excited states, and are of interest for studies of ion-molecule reactions at low temperatures.
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Affiliation(s)
- A Deller
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - S D Hogan
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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Zhelyazkova V, Žeško* M, Schmutz H, Agner JA, Merkt F. Fluorescence-lifetime-limited trapping of Rydberg helium atoms on a chip. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1600060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- V. Zhelyazkova
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
| | - M. Žeško*
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
| | - H. Schmutz
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
| | - J. A. Agner
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
| | - F. Merkt
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
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Grimes DD, Barnum TJ, Zhou Y, Colombo AP, Field RW. Coherent laser-millimeter-wave interactions en route to coherent population transfer. J Chem Phys 2017; 147:144201. [DOI: 10.1063/1.4997624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David D. Grimes
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Timothy J. Barnum
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yan Zhou
- JILA, National Institute of Standards and Technology, Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Anthony P. Colombo
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert W. Field
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Allmendinger P, Deiglmayr J, Höveler K, Schullian O, Merkt F. Observation of enhanced rate coefficients in the H 2 + + H 2 → H 3 + + H reaction at low collision energies. J Chem Phys 2016; 145:244316. [DOI: 10.1063/1.4972130] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Allmendinger P, Deiglmayr J, Schullian O, Höveler K, Agner JA, Schmutz H, Merkt F. New Method to Study Ion–Molecule Reactions at Low Temperatures and Application to the Reaction. Chemphyschem 2016; 17:3596-3608. [DOI: 10.1002/cphc.201600828] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Pitt Allmendinger
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Johannes Deiglmayr
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Otto Schullian
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Katharina Höveler
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Josef A. Agner
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Hansjürg Schmutz
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Frédéric Merkt
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
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Hogan SD. Rydberg-Stark deceleration of atoms and molecules. EPJ TECHNIQUES AND INSTRUMENTATION 2016; 3:2. [PMID: 32355605 PMCID: PMC7175735 DOI: 10.1140/epjti/s40485-015-0028-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/27/2015] [Indexed: 06/06/2023]
Abstract
The large electric dipole moments associated with highly excited Rydberg states of atoms and molecules make gas-phase samples in these states very well suited to deceleration and trapping using inhomogeneous electric fields. The methods of Rydberg-Stark deceleration with which this can be achieved are reviewed here. Using these techniques, the longitudinal motion of beams of atoms and molecules moving at speeds as high as 2500 m/s have been manipulated, with changes in kinetic energy of up to |Δ E kin|=1.3×10-20 J (|Δ E kin|/e=80 meV or |Δ E kin|/h c=650 cm -1) achieved, while decelerated and trapped samples with number densities of 106- 107 cm -3 and translational temperatures of ∼150 mK have been prepared. Applications of these samples in areas of research at the interface between physics and physical chemistry are discussed.
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Affiliation(s)
- Stephen D. Hogan
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
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Sprecher D, Merkt F. Observation of g/u-symmetry mixing in the high-n Rydberg states of HD. J Chem Phys 2014; 140:124313. [PMID: 24697447 DOI: 10.1063/1.4868024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The structure and dynamics of high-n Rydberg states belonging to series converging to the (v(+) = 0, N(+) = 0-2) levels of the X(+) (2)Σ(g)(+)electronic ground state of HD(+) were studied by high-resolution spectroscopy from the GK (1)Σ(g)(+) (v = 1, N = 1) state under field-free conditions. Three effects of g/u-symmetry breaking were detected: (i) Single-photon transitions from the GK (v = 1, N = 1) state of gerade symmetry to the 30d21 and 31g22 Rydberg states of gerade symmetry were observed after careful compensation of the stray electric fields. (ii) The singlet 61p12 Rydberg state of ungerade symmetry was found to autoionize to the N(+) = 0, ℓ = 2 ionization continuum of gerade symmetry with a lifetime of 77(10) ns. (iii) Shifts of up to 20 MHz induced by g/u-symmetry mixing were measured for members of the np11 Rydberg series which lie close to nd21 Rydberg states. These observations were analyzed in the framework of multichannel quantum-defect theory. From the observed level shifts, the off-diagonal eigenquantum-defect element μ(pd) of singlet-π symmetry was determined to be 0.0023(3) and the corresponding autoionization dynamics could be characterized. The ionization energy of the GK (v = 1, N = 1) state of HD was determined to be 12 710.544 23(10) cm(-1).
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Affiliation(s)
- Daniel Sprecher
- Laboratorium für Physikalische Chemie, ETH-Zürich, 8093 Zürich, Switzerland
| | - Frédéric Merkt
- Laboratorium für Physikalische Chemie, ETH-Zürich, 8093 Zürich, Switzerland
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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
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Sprecher D, Beyer M, Merkt F. Precision measurement of the ionisation energy of the 3dσ GK state of H2. Mol Phys 2013. [DOI: 10.1080/00268976.2013.788743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- D. Sprecher
- Laboratorium für Physikalische Chemie, ETH Zürich , Zurich, Switzerland
| | - M. Beyer
- Laboratorium für Physikalische Chemie, ETH Zürich , Zurich, Switzerland
| | - F. Merkt
- Laboratorium für Physikalische Chemie, ETH Zürich , Zurich, Switzerland
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van de Meerakker SYT, Bethlem HL, Vanhaecke N, Meijer G. Manipulation and Control of Molecular Beams. Chem Rev 2012; 112:4828-78. [DOI: 10.1021/cr200349r] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Hendrick L. Bethlem
- Institute for Lasers, Life and
Biophotonics, VU University Amsterdam,
De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Nicolas Vanhaecke
- Laboratoire Aimé Cotton, CNRS, Bâtiment 505, Université Paris-Sud,
91405 Orsay, France
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin,
Germany
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Hogan SD, Allmendinger P, Sassmannshausen H, Schmutz H, Merkt F. Surface-electrode Rydberg-Stark decelerator. PHYSICAL REVIEW LETTERS 2012; 108:063008. [PMID: 22401069 DOI: 10.1103/physrevlett.108.063008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Indexed: 05/31/2023]
Abstract
Hydrogen atoms in Rydberg states with principal quantum numbers between 23 and 70 have been accelerated, decelerated, and electrostatically trapped using a surface-electrode Rydberg-Stark decelerator. By applying a set of oscillating electrical potentials to a two-dimensional array of electrodes on a printed circuit board (PCB), a continuously moving, three-dimensional electric trap with a predefined velocity and acceleration is generated. From an initial longitudinal velocity of 760 m/s, final velocities of the Rydberg atoms ranging from 1200 m/s to zero velocity in the laboratory-fixed frame of reference were achieved. Accelerated or decelerated atoms were detected directly by pulsed electric-field ionization. Atoms trapped at zero mean velocity above the PCB were reaccelerated off the PCB before field ionization.
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Affiliation(s)
- S D Hogan
- Laboratorium für Physikalische Chemie, ETH Zürich, Zürich, Switzerland
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Hogan SD, Motsch M, Merkt F. Deceleration of supersonic beams using inhomogeneous electric and magnetic fields. Phys Chem Chem Phys 2011; 13:18705-23. [DOI: 10.1039/c1cp21733j] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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