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Forbes R, Boguslavskiy AE, Wilkinson I, Underwood JG, Stolow A. Excited state wavepacket dynamics in NO 2 probed by strong-field ionization. J Chem Phys 2017; 147:054305. [PMID: 28789534 DOI: 10.1063/1.4996461] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an experimental femtosecond time-resolved study of the 399 nm excited state dynamics of nitrogen dioxide using channel-resolved above threshold ionization (CRATI) as the probe process. This method relies on photoelectron-photoion coincidence and covariance to correlate the strong-field photoelectron spectrum with ionic fragments, which label the channel. In all ionization channels observed, we report apparent oscillations in the ion and photoelectron yields as a function of pump-probe delay. Further, we observe the presence of a persistent, time-invariant above threshold ionization comb in the photoelectron spectra associated with most ionization channels at long time delays. These observations are interpreted in terms of single-pump-photon excitation to the first excited electronic X̃ 2A1 state and multi-pump-photon excitations to higher-lying states. The short time delay (<100 fs) dynamics in the fragment channels show multi-photon pump signatures of higher-lying neutral state dynamics, in data sets recorded with higher pump intensities. As expected for pumping NO2 at 399 nm, non-adiabatic coupling was seen to rapidly re-populate the ground state following excitation to the first excited electronic state, within 200 fs. Subsequent intramolecular vibrational energy redistribution results in the spreading of the ground state vibrational wavepacket into the asymmetric stretch coordinate, allowing the wavepacket to explore nuclear geometries in the asymptotic region of the ground state potential energy surface. Signatures of the vibrationally "hot" ground state wavepacket were observed in the CRATI spectra at longer time delays. This study highlights the complex and sometimes competing phenomena that can arise in strong-field ionization probing of excited state molecular dynamics.
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Affiliation(s)
- Ruaridh Forbes
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Andrey E Boguslavskiy
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Iain Wilkinson
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Jonathan G Underwood
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Albert Stolow
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
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Elkharrat C, Picard YJ, Billaud P, Cornaggia C, Garzella D, Perdrix M, Houver JC, Lucchese RR, Dowek D. Ion Pair Formation in Multiphoton Excitation of NO2 Using Linearly and Circularly Polarized Femtosecond Light Pulses: Kinetic Energy Distribution and Fragment Recoil Anisotropy. J Phys Chem A 2010; 114:9902-18. [DOI: 10.1021/jp103672h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Elkharrat
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - Y. J. Picard
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - P. Billaud
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - C. Cornaggia
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - D. Garzella
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - M. Perdrix
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - J. C. Houver
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - R. R. Lucchese
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
| | - D. Dowek
- Institut des Sciences Moléculaires d’Orsay, UMR8214 Univ Paris-Sud et CNRS, Bat. 350, F-91405 Orsay Cedex, France, Service Photons Atomes & Molécules, CEA IRAMIS, Service des Photons, Atomes et Molécules, Saclay, Bat. 522, F-91191 Gif-sur-Yvette, France, and Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
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Hamard JB, Cireasa R, Chatel B, Blanchet V, Whitaker BJ. Quantum interference in NO2. J Phys Chem A 2010; 114:3167-75. [PMID: 20070094 DOI: 10.1021/jp909129g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper investigates the origin of a quantum interference observed when NO(2) is dissociatively ionized by short pulses of ultraviolet light. We describe time-resolved measurements of NO(+), O(+), and NO(2)(+) ions produced following the interaction of NO(2) with a approximately 70 fs duration pulse centered close to 400 nm and a subsequent time-delayed probe pulse close to 269, 205, or 400 nm. A quantum beat oscillation with a period of 524 fs and a characteristic damping time of 8 ps is observed on all transient ion signals. We investigate the effect of tuning the central wavelength of the excitation pulse over a 12 nm range, and we discuss the potential importance of three possible multiphoton pathways involving one, two, and three pump photons. We conclude that the ionization pathway responsible for the beat signal is most likely due to a process involving the absorption of two pump photons and two probe photons. This presents an interesting problem with respect to the interpretation of the mechanism responsible for the quantum interference signature since the electronic states of NO(2) reached at the two-photon level are all thought to be extremely short-lived and to dissociate on a time scale that is far shorter than the characteristic damping time of the oscillatory signals. We suggest that a possible explanation for the observed dynamics is associated with a minor dissociation channel of the (2)(2)B(2) state of NO(2) through its interaction with the longer lived (2)(2)A(1) state.
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Affiliation(s)
- J B Hamard
- Université de Toulouse, UPS, 118 route de Narbonne, F-31062 Toulouse, France
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