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Waters MDJ, Wörner HJ. The ultrafast vibronic dynamics of ammonia's D̃ state. Phys Chem Chem Phys 2022; 24:23340-23349. [PMID: 36129030 DOI: 10.1039/d2cp03117e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using vacuum-ultraviolet time-resolved velocity map imaging of photoelectrons, we study ultrafast coupled electronic and nuclear dynamics in low-lying Rydberg states of ammonia. Vibrationally-resolved internal vibrational relaxation (IVR) is observed in a progression of the e' bending modes. This vibrational progression is only observed in the D̃ state, and is lost upon ultrafast internal conversion to the C̃ and B̃ electronic states. Due to the ultrashort time scale of the internal conversion (ca. 64 fs), and the vibronic resolution, the non-adiabatic coupling vectors are identified and verified with ab initio calculations. The time-scale of this IVR process is highly surprising and significant because IVR is usually treated as an incoherent process that proceeds statistically, according to a "Fermi's Golden Rule"-like model, where the process scales with the available degrees of freedom. Here, we show that it can be highly non-statistical, restricted to only a very small subset of vibrational motions.
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Affiliation(s)
- Max D J Waters
- Laboratory for Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
| | - Hans Jakob Wörner
- Laboratory for Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
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2
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Fan JN, Cui TT, Qin ZB, Zheng XF, Cui ZF. Experimental and theoretical study on p-chlorofluorobenzene in the S0, S1 and D0 states. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp2001005] [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]
Affiliation(s)
- Jia-nan Fan
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Wuhu 241000, China
| | - Ting-ting Cui
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Wuhu 241000, China
| | - Zheng-bo Qin
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Wuhu 241000, China
| | - Xian-feng Zheng
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Wuhu 241000, China
| | - Zhi-feng Cui
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Wuhu 241000, China
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Hao Q, Deng X, Long J, Wang Y, Abulimiti B, Zhang B. Real-time observation of cascaded electronic relaxation processes in p-Fluorotoluene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 183:109-115. [PMID: 28441538 DOI: 10.1016/j.saa.2017.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/31/2017] [Accepted: 04/17/2017] [Indexed: 06/07/2023]
Abstract
Ultrafast electronic relaxation processes following two photoexcitation of 400nm in p-Fluorotoluene (pFT) have been investigated utilizing time-resolved photoelectron imaging coupled with time-resolved mass spectroscopy. Cascaded electronic relaxation processes started from the electronically excited S2 state are directly imaged in real time and well characterized by two distinct time constants of ~85±10fs and 2.4±0.3ps. The rapid component corresponds to the lifetime of the initially excited S2 state, including the structure relaxation from the Franck-Condon region to the conical intersection of S2/S1 and the subsequent internal conversion to the highly excited S1 state. While, the slower relaxation constant is attributed to the further internal conversion to the high levels of S0 from the secondarily populated S1 locating in the channel three region. Moreover, dynamical differences with benzene and toluene of analogous structures, including, specifically, the slightly slower relaxation rate of S2 and the evidently faster decay of S1, are also presented and tentatively interpreted as the substituent effects. In addition, photoelectron kinetic energy and angular distributions reveal the feature of accidental resonances with low-lying Rydberg states (the 3p, 4s and 4p states) during the multi-photon ionization process, providing totally unexpected but very interesting information for pFT.
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Affiliation(s)
- Qiaoli Hao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xulan Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jinyou Long
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yanmei Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Bumaliya Abulimiti
- College of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, PR China.
| | - Bing Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
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Qu Z, Qin Z, Zheng X, Wang H, Yao G, Zhang X, Cui Z. Slow-electron velocity-map imaging study of aniline via resonance-enhanced two-photon ionization method. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 173:432-438. [PMID: 27705848 DOI: 10.1016/j.saa.2016.09.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/31/2016] [Accepted: 09/26/2016] [Indexed: 06/06/2023]
Abstract
Slow electron velocity-map imaging (SEVI) of aniline has been investigated via two-color resonant-enhanced two-photo (1+1') ionization (2C-R2PI) method. A number of vibrational frequencies in the first excited state of neutral (S1) and 2B1 ground electronic state of cation (D0) have been accurately determined. In addition, photoelectron angular distributions (PADs) in the two-step transitions are presented and reveal a near threshold shape resonance in the ionization of aniline. The SEVI spectra taken via various S1 intermediate states provide the detailed vibrational structures of D0 state and directly deduce the accurate adiabatic ionization potential (IP) of 62,271±6cm-1. Ab initio calculations excellently reproduce the experimental IP value (Theo. 62,242cm-1). For most vibrational modes, good agreement between theoretical and experimental frequencies in the S0 and D0 states of aniline is obtained to aid us to clearly assign vibrational modes. Especially, the vibrational frequencies calculated at the CASSCF level are much better consistent with experimental data than that obtained using the TDDFT and CIS methods.
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Affiliation(s)
- Zehua Qu
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Zhengbo Qin
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
| | - Xianfeng Zheng
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China.
| | - Hui Wang
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Guanxin Yao
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Xianyi Zhang
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Zhifeng Cui
- Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu, Anhui 241000, China
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Midgley J, Davies JA, Reid KL. Comment on “Photoelectron angular distributions as a probe of alignment in a polyatomic molecule: Picosecond time- and angle-resolved photoelectron spectroscopy of S1 p-difluorobenzene” [J. Chem. Phys. 111, 1438 (1999)]. J Chem Phys 2013; 139:117101. [DOI: 10.1063/1.4821765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Staniforth M, Daly S, Reid KL, Powis I. A generic π* shape resonance observed in energy-dependent photoelectron angular distributions from two-colour, resonant multiphoton ionization of difluorobenzene isomers. J Chem Phys 2013; 139:064304. [DOI: 10.1063/1.4817324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Reid KL. Photoelectron angular distributions: developments in applications to isolated molecular systems. Mol Phys 2012. [DOI: 10.1080/00268976.2011.640292] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Niu D, Ogi Y, Suzuki YI, Suzuki T. Photoelectron Imaging Spectroscopy of S1(1B2u π,π*) Benzene via 611n (n = 0−3) Levels. J Phys Chem A 2011; 115:2096-102. [DOI: 10.1021/jp110557n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dongmei Niu
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, RIKEN, Wako 351-0198 Japan
| | - Yoshihiro Ogi
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, RIKEN, Wako 351-0198 Japan
| | - Yoshi-Ichi Suzuki
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, RIKEN, Wako 351-0198 Japan
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Chemical Dynamics Laboratory, RIKEN Advanced Science Institute, RIKEN, Wako 351-0198 Japan
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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Stolow A, Underwood JG. Time-Resolved Photoelectron Spectroscopy of Nonadiabatic Dynamics in Polyatomic Molecules. ADVANCES IN CHEMICAL PHYSICS 2008. [DOI: 10.1002/9780470259498.ch6] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Abstract
Femtosecond time-resolved photoelectron imaging (TRPEI) is a variant of time-resolved photoelectron spectroscopy used in the study of gas-phase photoinduced dynamics. A new observable, time-dependent photoionization-differential cross section provides useful information on wave-packet motions, electronic dephasing, and photoionization dynamics. This review describes fundamental issues and the most recent works involving TRPEI.
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Affiliation(s)
- Toshinori Suzuki
- Chemical Dynamics Laboratory, RIKEN (Institute of Physical and Chemical Research), Wako 351-0198, Japan.
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Das A, Poliakoff ED, Lucchese RR, Bozek JD. Launching a particle on a ring: b2u→ke2g ionization of C6F6. J Chem Phys 2006; 125:164316. [PMID: 17092082 DOI: 10.1063/1.2360532] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Evidence is presented demonstrating that an electron launched into the continuum is trapped in an unprecedented quasibound state, namely, one that extends through the backbone of the six-member carbon ring of C6F6. The mode specificity of the vibrational sensitivity to the electron trapping provides an experimental signature for this phenomenon, while adiabatic static model-exchange scattering calculations are used to map the wave function, which corroborate the interpretation.
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Affiliation(s)
- Aloke Das
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Hammond CJ, Reid KL, Ronayne KL. Observation of a simple vibrational wavepacket in a polyatomic molecule via time-resolved photoelectron velocity-map imaging: A prototype for time-resolved IVR studies. J Chem Phys 2006; 124:201102. [PMID: 16774305 DOI: 10.1063/1.2204596] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have prepared a coherent superposition of the two components of a Fermi resonance in the S1 state of toluene at approximately 460 cm(-1) with a approximately 1 ps laser pulse and monitored time-resolved photoelectron velocity-map images. The photoelectron intensities oscillate with time in a manner that depends on their kinetic energy, even though full vibrational resolution in the cation is not achieved. Analysis of the time-dependent photoelectron spectra enables information on the composition of the S1 wavepacket to be deduced. Such an experiment, in which a whole set of partially dispersed cation vibrational states are detected simultaneously, suggests an efficient method of studying intramolecular vibrational energy redistribution processes in excited states.
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Affiliation(s)
- Chris J Hammond
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Bellm SM, Davies JA, Whiteside PT, Guo J, Powis I, Reid KL. An unusual π* shape resonance in the near-threshold photoionization of S1 para-difluorobenzene. J Chem Phys 2005; 122:224306. [PMID: 15974667 DOI: 10.1063/1.1927523] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Previously reported dramatic changes in photoelectron angular distributions (PADs) as a function of photoelectron kinetic energy following the ionization of S1 p-difluorobenzene are shown to be explained by a shape resonance in the b(2g) symmetry continuum. The characteristics of this resonance are clearly demonstrated by a theoretical multiple-scattering treatment of the photoionization dynamics. New experimental data are presented which demonstrate an apparent insensitivity of the PADs to both vibrational motion and prepared molecular alignment, however, the calculations suggest that strong alignment effects may nevertheless be recognized in the detail of the comparison with experimental data. The apparent, but unexpected, indifference to vibrational excitation is rationalized by considering the nature of the resonance. The correlation of this shape resonance in the continuum with a virtual pi* antibonding orbital is considered. Because this orbital is characteristic of the benzene ring, the existence of similar resonances in related substituted benzenes is discussed.
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Affiliation(s)
- Susan M Bellm
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Bellm SM, Reid KL. Evaluation of the use of photoelectron imaging in obtaining photoelectron spectra and angular distributions: comparison with the field-free time-of-flight method. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.07.088] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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