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Barnum TJ, Clausen G, Jiang J, Coy SL, Field RW. Long-range model of vibrational autoionization in core-nonpenetrating Rydberg states of NO. J Chem Phys 2021; 155:244303. [PMID: 34972375 DOI: 10.1063/5.0070879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In high orbital angular momentum (ℓ ≥ 3) Rydberg states, the centrifugal barrier hinders the close approach of the Rydberg electron to the ion-core. As a result, these core-nonpenetrating Rydberg states can be well described by a simplified model in which the Rydberg electron is only weakly perturbed by the long-range electric properties (i.e., multipole moments and polarizabilities) of the ion-core. We have used a long-range model to describe the vibrational autoionization dynamics of high-ℓ Rydberg states of nitric oxide (NO). In particular, our model explains the extensive angular momentum exchange between the ion-core and the Rydberg electron that had been previously observed in vibrational autoionization of f (ℓ = 3) Rydberg states. These results shed light on a long-standing mechanistic question around these previous observations and support a direct, vibrational mechanism of autoionization over an indirect, predissociation-mediated mechanism. In addition, our model correctly predicts newly measured total decay rates of g (ℓ = 4) Rydberg states because for ℓ ≥ 4, the non-radiative decay is dominated by autoionization rather than predissociation. We examine the predicted NO+ ion rotational state distributions generated by vibrational autoionization of g states and discuss applications of our model to achieve quantum state selection in the production of molecular ions.
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Affiliation(s)
- Timothy J Barnum
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Gloria Clausen
- Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Jun Jiang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Stephen L Coy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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2
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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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González-Férez R, Shertzer J, Sadeghpour HR. Ultralong-Range Rydberg Bimolecules. PHYSICAL REVIEW LETTERS 2021; 126:043401. [PMID: 33576643 DOI: 10.1103/physrevlett.126.043401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
We predict that ultralong-range Rydberg bimolecules form in collisions between polar molecules in cold and ultracold settings. The interaction of Λ-doublet nitric oxide (NO) with long-lived Rydberg NO(nf, ng) molecules forms ultralong-range Rydberg bimolecules with GHz energies and kilo-Debye permanent electric dipole moments. The Hamiltonian includes both the anisotropic charge-molecular dipole interaction and the electron-NO scattering. The rotational constant for the Rydberg bimolecules is in the MHz range, allowing for microwave spectroscopy of rotational transitions in Rydberg bimolecules. Considerable orientation of NO dipole can be achieved. The Rydberg molecules described here hold promise for studies of a special class of long-range bimolecular interactions.
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Affiliation(s)
- Rosario González-Férez
- Instituto Carlos I de Física Teórica y Computacional, and Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada, Spain
- ITAMP, Center for Astrophysics, Harvard & Smithsonian, Cambridge, Massachusetts 02138 USA
| | - Janine Shertzer
- ITAMP, Center for Astrophysics, Harvard & Smithsonian, Cambridge, Massachusetts 02138 USA
- Department of Physics, College of the Holy Cross, Worcester, Massachusetts 01610, USA
| | - H R Sadeghpour
- ITAMP, Center for Astrophysics, Harvard & Smithsonian, Cambridge, Massachusetts 02138 USA
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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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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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Prozument K, Colombo AP, Zhou Y, Park GB, Petrović VS, Coy SL, Field RW. Chirped-pulse millimeter-wave spectroscopy of Rydberg-Rydberg transitions. PHYSICAL REVIEW LETTERS 2011; 107:143001. [PMID: 22107187 DOI: 10.1103/physrevlett.107.143001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Indexed: 05/31/2023]
Abstract
Transitions between Rydberg states of Ca atoms, in a pulsed, supersonic atomic beam, are directly detected by chirped-pulse millimeter-wave spectroscopy. Broadband, high-resolution spectra with accurate relative intensities are recorded instantly. Free induction decay (FID) of atoms, polarized by the chirped pulse, at their Rydberg-Rydberg transition frequencies, is heterodyne detected, averaged in the time domain, and Fourier transformed into the frequency domain. Millimeter-wave transient nutations are observed, and the possibility of FID evolving to superradiance is discussed.
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Affiliation(s)
- Kirill Prozument
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Wang YH, Mineo H, Chao SD, Selzle HL, Neusser HJ, Schlag EW, Teranishi Y, Lin SH. A master equation approach to the dynamics of zero electron kinetic energy (ZEKE) states and ZEKE spectroscopy. J Chem Phys 2011; 134:064316. [PMID: 21322689 DOI: 10.1063/1.3547363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have theoretically studied important dynamic processes involved in zero electron kinetic energy (ZEKE) spectroscopy using the density matrix method with the inverse Born-Oppenheimer approximation basis sets. In ZEKE spectroscopy, the ZEKE Rydberg states are populated by laser excitation (either a one- or two-photon process), which is followed by autoionizations and l-mixing due to a stray field. The discrimination field is then applied to ionize loosely bound electrons in the ZEKE states. This is followed by using the extraction field to extract electrons from the ZEKE levels which have a strength comparable to that of the extraction field. These extracted electrons are measured for the relative intensities of the ion states under investigation. The spectral positions are determined by the applied laser wavelength and modified by the extraction electric field. In this paper, all of these processes are conducted within the context of the density matrix method. The density matrix method can provide not only the dynamics of system's population and coherence (or phase) but also the rate constants of the processes involved in the ZEKE spectroscopy. Numerical examples are given to demonstrate the theoretical treatments.
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Affiliation(s)
- Yi-Hsieh Wang
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
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9
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Clarson B, Procter S, Goodgame A, Softley T. The Stark effect in the predissociating Rydberg states of NO. Mol Phys 2008. [DOI: 10.1080/00268970802298753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Softley TP. Applications of molecular Rydberg states in chemical dynamics and spectroscopy. INT REV PHYS CHEM 2007. [DOI: 10.1080/01442350310001652940] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- T. P. Softley
- a Department of Chemistry , Chemistry Research Laboratory, University of Oxford , Mansfield Rd, Oxford OX1 3TA, UK
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Yamakita Y, Procter SR, Goodgame AL, Softley TP, Merkt F. Deflection and deceleration of hydrogen Rydberg molecules in inhomogeneous electric fields. J Chem Phys 2004; 121:1419-31. [PMID: 15260687 DOI: 10.1063/1.1763146] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hydrogen molecules are excited in a molecular beam to Rydberg states around n=17-18 and are exposed to the inhomogeneous electric field of an electric dipole. The large dipole moment produced in the selected Stark eigenstates leads to strong forces on the H2 molecules in the inhomogeneous electric field. The trajectories of the molecules are monitored using ion-imaging and time of flight measurements. With the dipole rods mounted parallel to the beam direction, the high-field-seeking and low-field-seeking Stark states are deflected towards and away from the dipole, respectively. The magnitude of the deflection is measured as a function of the parabolic quantum number k and of the duration of the applied field. It is also shown that a large deflection is observed when populating the (17d2)1 state at zero field and switching the dipole field on after a delay. With the dipole mounted perpendicular to the beam direction, the molecules are either accelerated or decelerated as they move towards the dipole. The Rydberg states are found to survive for over 100 micros after the dipole field is switched off before being ionized at the detector and the time of flight is measured. A greater percentage change in kinetic energy is achieved by initial seeding of the beam in helium or neon followed by inhomogeneous field deceleration/acceleration. Molecular dynamics trajectory simulations are presented highlighting the extent to which the trajectories can be predicted based on the known Stark map. The spectroscopy of the populated states is discussed in detail and it is established that the N+=2, J=1, MJ=0 states populated here have a special stability with respect to decay by predissociation.
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Affiliation(s)
- Y Yamakita
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
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Smith RAL, Stavros VG, Verlet JRR, Fielding HH, Townsend D, Softley TP. The role of phase in molecular Rydberg wave packet dynamics. J Chem Phys 2003. [DOI: 10.1063/1.1589473] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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14
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Mass-analyzed Threshold Ionization Spectrometry with Scrambling Field Optimized for the Study of State-selective Ion Reaction Dynamics. B KOREAN CHEM SOC 2002. [DOI: 10.5012/bkcs.2002.23.9.1247] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Goodgame AL, Dickinson H, Mackenzie SR, Softley TP. The Stark effect in the v[sup +]=1 autoionizing Rydberg states of NO. J Chem Phys 2002. [DOI: 10.1063/1.1450552] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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17
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Murgu E, Martin JDD, Gallagher TF. Stabilization of predissociating nitric oxide Rydberg molecules using microwave and radio-frequency fields. J Chem Phys 2001. [DOI: 10.1063/1.1400788] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Warntjes JBM, Noordam LD. Measuring the predissociation and rotational autoionization of the vibrationless Rydberg series in ammonia. J Chem Phys 2001. [DOI: 10.1063/1.1389303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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20
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Nagesha K, Pinnaduwage L. Magnetic and electric field-induced enhancements in laser-induced anion formation. Chem Phys Lett 1999. [DOI: 10.1016/s0009-2614(99)00903-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Warntjes JBM, Robicheaux F, Bakker JM, Noordam LD. Autoionizing Rydberg states of NO in strong electric fields. J Chem Phys 1999. [DOI: 10.1063/1.479533] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Remacle F, Vrakking MJJ. Decay Dynamics of the Predissociating High Rydberg States of NO. J Phys Chem A 1998. [DOI: 10.1021/jp982053x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- F. Remacle
- Département de Chimie, B6, Université de Liège, B 4000 Liège, Belgium
| | - Marc J. J. Vrakking
- FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
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Vigliotti F, Zerza G, Chergui M, Rubayo-Soneira J. Lifetime lengthening of molecular Rydberg states in the condensed phase. J Chem Phys 1998. [DOI: 10.1063/1.476946] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Held A, Baranov LY, Selzle HL, Schlag EW. Lifetime control in Rydberg states using fast switching DC electric fields. Chem Phys Lett 1998. [DOI: 10.1016/s0009-2614(98)00615-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Merkt F, Schmutz H. Very high resolution spectroscopy of high Rydberg states of the argon atom. J Chem Phys 1998. [DOI: 10.1063/1.476464] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
The unusual properties of high molecular Rydberg states with principal quantum number n>>100 have enabled the development of new research tools for the study of molecules and ions in the gas phase. These tools range from spectroscopic techniques such as zero kinetic energy (ZEKE) photoelectron spectroscopy and mass-analyzed threshold ionization (MATI) spectroscopy to techniques that are suited to the investigation of photodissociation processes, bimolecular reactions, and state-selected ion-molecule reactions. This review summarizes recent progress in the understanding of the properties of high molecular Rydberg states and gives an overview of recent chemical applications of these states.
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Affiliation(s)
- F Merkt
- Laboratorium fur Physikalische Chemie ETH-Zurich Zurich CH-8092 Switzerland.
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Vrakking MJJ. Role of Core Interactions and External Perturbations in the Autoionization of Xe. J Phys Chem A 1997. [DOI: 10.1021/jp970756t] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marc J. J. Vrakking
- FOM Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
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Matsui H, Behm JM, Grant ER. Photoselection and the Appearance of Franck−Condon-Forbidden Thresholds in the ZEKE Spectrum of NO2. J Phys Chem A 1997. [DOI: 10.1021/jp970556h] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroshi Matsui
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Jane M. Behm
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Edward R. Grant
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
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30
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Remacle F, Levine RD. Physical aspects and quantitative theory of time resolved spectroscopy of high molecular Rydberg states. J Chem Phys 1997. [DOI: 10.1063/1.475142] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Biexponential decay of peak intensities in the zero electron kinetic energy pulsed field ionization of HCl. Chem Phys Lett 1997. [DOI: 10.1016/s0009-2614(97)00162-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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