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Ampadu Boateng D, Word MD, Gutsev LG, Jena P, Tibbetts KM. Conserved Vibrational Coherence in the Ultrafast Rearrangement of 2-Nitrotoluene Radical Cation. J Phys Chem A 2019; 123:1140-1152. [DOI: 10.1021/acs.jpca.8b11723] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Derrick Ampadu Boateng
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Mi’Kayla D. Word
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Lavrenty G. Gutsev
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Puru Jena
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Katharine Moore Tibbetts
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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Yatsuhashi T, Nakashima N. Multiple ionization and Coulomb explosion of molecules, molecular complexes, clusters and solid surfaces. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2018. [DOI: 10.1016/j.jphotochemrev.2017.12.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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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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Branching and competition of ultrafast photochemical reactions of cyclooctatriene and bicyclooctadiene. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kosma K, Trushin SA, Fuß W, Schmid WE. Cyclohexadiene ring opening observed with 13 fs resolution: coherent oscillations confirm the reaction path. Phys Chem Chem Phys 2009; 11:172-81. [DOI: 10.1039/b814201g] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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7
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Kosma K, Trushin SA, Fuss W, Schmid WE. Ultrafast Dynamics and Coherent Oscillations in Ethylene and Ethylene-d4 Excited at 162 nm. J Phys Chem A 2008; 112:7514-29. [DOI: 10.1021/jp803548c] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- K. Kosma
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - S. A. Trushin
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - W. Fuss
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - W. E. Schmid
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
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Trushin S, Kosma K, Fuß W, Schmid W. Wavelength-independent ultrafast dynamics and coherent oscillation of a metal–carbon stretch vibration in photodissociation of Cr(CO)6 in the region of 270–345nm. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.09.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Pradhan T, Ghoshal P, Biswas R. Excited State Intramolecular Charge Transfer Reaction in Binary Mixtures of Water and Tertiary Butanol (TBA): Alcohol Mole Fraction Dependence. J Phys Chem A 2008; 112:915-24. [DOI: 10.1021/jp0770460] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Tuhin Pradhan
- Department of Chemical, Biological and Macromolecular Sciences, and Unit for Nanoscience and Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake City, Kolkata 700 098, India
| | - Piue Ghoshal
- Department of Chemical, Biological and Macromolecular Sciences, and Unit for Nanoscience and Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake City, Kolkata 700 098, India
| | - Ranjit Biswas
- Department of Chemical, Biological and Macromolecular Sciences, and Unit for Nanoscience and Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake City, Kolkata 700 098, India
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Pradhan T, Biswas R. Electrolyte-Concentration and Ion-Size Dependence of Excited-State Intramolecular Charge-Transfer Reaction in (Alkylamino)benzonitriles: Time-Resolved Fluorescence Emission Studies. J Phys Chem A 2007; 111:11524-30. [DOI: 10.1021/jp075825a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Tuhin Pradhan
- Department of Chemical, Biological & Macromolecular Sciences, and Unit for Nano Science & Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700 098, India
| | - Ranjit Biswas
- Department of Chemical, Biological & Macromolecular Sciences, and Unit for Nano Science & Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700 098, India
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Pradhan T, Biswas R. Electrolyte-Concentration and Ion-Size Dependence of Excited-State Intramolecular Charge-Transfer Reaction in (Alkylamino)benzonitriles: Steady-State Spectroscopic Studies. J Phys Chem A 2007; 111:11514-23. [DOI: 10.1021/jp075820d] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tuhin Pradhan
- Department of Chemical, Biological & Macromolecular Sciences, and Unit for Nano Science & Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700 098, India
| | - Ranjit Biswas
- Department of Chemical, Biological & Macromolecular Sciences, and Unit for Nano Science & Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700 098, India
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Pigliucci A, Duvanel G, Daku LML, Vauthey E. Investigation of the Influence of Solute−Solvent Interactions on the Vibrational Energy Relaxation Dynamics of Large Molecules in Liquids. J Phys Chem A 2007; 111:6135-45. [PMID: 17591756 DOI: 10.1021/jp069010y] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The influence of solute-solvent interactions on the vibrational energy relaxation dynamics of perylene and substituted perylenes in the first singlet excited-state upon excitation with moderate (<0.4 eV) excess energy has been investigated by monitoring the early narrowing of their fluorescence spectrum. This narrowing was found to occur on timescales ranging from a few hundreds of femtoseconds to a few picoseconds. Other processes, such as a partial decay of the fluorescence anisotropy and the damping of a low-frequency oscillation due to the propagation of a vibrational wavepacket, were found to take place on a very similar time scale. No significant relationship between the strength of nonspecific solute-solvent interactions and the vibrational energy relaxation dynamics of the solutes could be evidenced. On the other hand, in alcohols the spectral narrowing is faster with a solute having H-bonding sites, indicating that this specific interaction tends to favor vibrational energy relaxation. No relationship between the dynamics of spectral narrowing and macroscopic solvent properties, such as the thermal diffusivity, could be found. On the other hand, a correlation between this narrowing dynamics and the number of low-frequency modes of the solvent molecules was evidenced. All these observations cannot be discussed with a model where vibrational energy relaxation occurs via two consecutive and dynamically well-separated steps, namely ultrafast intramolecular vibrational redistribution followed by slower vibrational cooling. On the contrary, the results indicate that both intra- and intermolecular vibrational energy redistribution processes are closely entangled and occur, at least partially, on similar timescales.
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Affiliation(s)
- Anatolio Pigliucci
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
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Fuss W, Schmid WE, Trushin SA, Billone PS, Leigh WJ. Forward and Backward Pericyclic Photochemical Reactions Have Intermediates in Common, Yet Cyclobutenes Break the Rules. Chemphyschem 2007; 8:592-8. [PMID: 17274091 DOI: 10.1002/cphc.200600639] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Photochemical pericyclic reactions are believed to proceed via a so-called pericyclic minimum on the lowest excited potential surface (S(1)), which is common to both the forward and backward reactions. Such a common intermediate has never been directly detected. The photointerconversion of 1,3-butadiene and cyclobutene is the prevailing prototype for such reactions, yet only diene ring closure proceeds with the stereospecificity that the Woodward-Hoffmann rules predict. This contrast seems to exclude a common intermediate. Using ultrafast spectroscopy, we show that the excited states of two cyclobutene/diene isomeric pairs are linked by not one, but by two common minima, p* and ct*. Starting from the diene side (cyclohepta-1,3-diene and cycloocta-1,3-diene), electrocyclic ring closure passes via the pericyclic minimum p*, whereas ct* is mainly responsible for cis-trans isomerization. Starting from the corresponding cyclobutenes (bicyclo[3.2.0]heptene-6 and bicyclo[4.2.0]octene-7), the forbidden isomer is formed from ct*. The path branches at the first (S(2)/S(1)) conical intersection towards p* and ct*. The fact that the energetically unfavorable ct* path can compete is ascribed to a dynamic effect: the momentum in C=C twist direction, acquired--such as in other olefins--in the Franck-Condon region of the cyclobutenes.
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Affiliation(s)
- Werner Fuss
- Max-Planck-Institut für Quantenoptik, 85741 Garching, Germany.
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Fuß W, Panja S, Schmid WE, Trushin SA. Competing ultrafast cis-trans isomerization and ring closure of cyclohepta-1,3-diene and cyclo-octa-1,3-diene. Mol Phys 2007. [DOI: 10.1080/00268970500417408] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- W. Fuß
- a Max-Planck-Institut für Quantenoptik , Germany
| | - S. Panja
- a Max-Planck-Institut für Quantenoptik , Germany
| | - W. E. Schmid
- a Max-Planck-Institut für Quantenoptik , Germany
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Fuss W, Schmid WE, Kuttan Pushpa K, Trushin SA, Yatsuhashi T. Ultrafast relaxation and coherent oscillations in aminobenzonitriles in the gas phase probed by intense-field ionization. Phys Chem Chem Phys 2007; 9:1151-69. [PMID: 17325762 DOI: 10.1039/b611877a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
4-Aminobenzonitrile derivatives have two excited states of similar energy: besides the benzene-like L(b) state (also termed "locally excited" or LE state) one with charge-transfer (CT) character that is slightly higher in the isolated molecules. The CT state can be lowered by solvents of suitable polarity, so that dual fluorescence can be observed in them. It is controversial along which coordinate this state is displaced, although the amino-group twist is a wide-spread assumption. We investigated a number of such compounds by transient ionization in the gas phase, initially exciting the higher-lying L(a) state (S(2)). Here we briefly review the previous results on 4-(dimethylamino)benzonitrile (the prototype of this class of molecules), 4-piperidino-, pyrrolidino- and pyrrolyl-benzonitrile and compare them with new results on 4-aminobenzonitrile and on the bridged derivative N-methyl-6-cyano-1,2,3,4-tetrahydroquinoline (NMC6). Although in the latter two molecules the CT state has never been detected before, we find the same relaxation path for all compounds: From S(2), the wave packet passes through a conical intersection (CI); from there part of it reaches the S(1) (L(b)) state directly, whereas another part temporarily populates the CT state (also in NMC6), from where it goes around the CI also to the L(b) well. The wave packet directly reaching the L(b) well oscillates there along coordinates involving amino-group twist and wagging or molecular arching and a quinoidal distortion. These coordinates must be components of the CI displacement vector. A vibration involving bond-length alternation of the benzene ring is ascribed to a momentum caused by the electronic symmetry change in the CI, i.e., to the nonadiabatic coupling vector. Also the CT state involves amino-group twist, as to conclude from the anisotropy of the corresponding signal. The six-membered aliphatic ring in NMC6 hinders the twist and raises the CT state to an energy that is, however, still below the L(a) state, so that it can be temporarily populated in a barrierless process. Also in aminobenzonitrile the CT state is between L(a) and L(b) and is reached from L(a) without a barrier. The twist is rationalized by vibronic interaction with a higher state that is pi-antibonding between the amino group and the aromatic ring.
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Affiliation(s)
- Werner Fuss
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
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Hättig C, Hellweg A, Köhn A. Intramolecular Charge-Transfer Mechanism in Quinolidines: The Role of the Amino Twist Angle. J Am Chem Soc 2006; 128:15672-82. [PMID: 17147377 DOI: 10.1021/ja0642010] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantum-chemical calculations with the approximate coupled-cluster singles-and-doubles model CC2 have been carried out for 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6). For this molecule dual fluorescence was experimentally observed, raising the discussion about the importance of the amino twist angle for this process. The calculations suggest that both the ground state and the normal fluorescent state are significantly twisted by 30 degrees -40 degrees and that the molecule is flexible enough to move into an even stronger twisted conformation (60 degrees -70 degrees ) in its intramolecular charge-transfer (ICT) state which is responsible for the anomalous fluorescence band. Such a conformation both minimizes the total energy in the S1 state and maximizes the dipole moment. The barrier from the normal fluorescent state to the ICT state region is very small. Comparison to the situation in the 1-methyl-derivative NMC6 suggests that a large alkyl substituent makes the preferably planar normal fluorescent state energetically unfavorable compared to the ICT state and thus promotes the occurrence of dual fluorescence.
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Affiliation(s)
- Christof Hättig
- Forschungszentrum Karlsruhe, Institute of Nanotechnology, D-76021 Karlsruhe, Germany
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Fuß W, Schmid W, Trushin S. Ultrafast photochemistry of cyclopentadiene: Competing hydrogen migration and electrocyclic ring closure. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dahl K, Biswas R, Ito N, Maroncelli M. Solvent Dependence of the Spectra and Kinetics of Excited-State Charge Transfer in Three (Alkylamino)benzonitriles. J Phys Chem B 2005; 109:1563-85. [PMID: 16851128 DOI: 10.1021/jp046605p] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Steady-state absorption and emission spectra and emission decay kinetics are reported for 4-aminobenzonitrile (ABN), 4-(1-azetidinyl)benzonitrile (P4C), 4-(1-pyrrolidinyl)benzonitrile (P5C), and 4-(1-piperidinyl)benzonitrile (P6C) in 24 room temperature solvents. In solvents of modest to high polarity, P4C, P5C, and P6C exhibit dual fluorescence and emission decays characteristic of the transformation from an initially prepared (LE) state to a more polar charge transfer (CT) state, whereas ABN does not undergo this reaction. The frequencies of the steady-state absorption and emission spectra of all of these solutes can be rationalized using a dielectric continuum description of the solvent and considering only the minima on the reactive surfaces, which are assumed to involve both an intramolecular (twisting) and a solvation coordinate. Characteristics of the gas-phase solutes deduced from this analysis are in good agreement with electronic structure calculations and indicate that differences in their spectra mainly reflect differences in the relative energies of the gas-phase LE and CT states. The relative yields of LE and CT emission are not described as satisfactorily by this model, and reasons for this failure are discussed. The kinetics of the LE --> CT reaction vary considerably with solute and solvent. In many solvents, the emission decays of P4C are reasonably described by a simple two-state kinetic scheme with time-independent rate constants. In P5C and P6C multiexponential decays are observed that reflect time-dependent shifts of the component spectra as well as time-dependent reaction rates. A simplified analysis of these complex dynamics provides estimates for both the free energy change Delta(r)G and (average) LE --> CT rate constant k(f) for a wide range of solute and solvent combinations. The driving force for reaction (-Delta(r)G) follows the order P6C > P5C > P4C and increases with increasing solvent polarity. The reaction rates are correlated to Delta(r)G and follow the opposite trend. The relationships observed between k(f) and Delta(r)G suggest that static solvent effects, i.e., barrier height changes, are the primary determinants of the solvent dependence in P4C. Correlations between barrier-corrected rates and solvation times suggest that dynamical solvent effects contribute substantially to the solvent dependence of the rates in P5C, and especially P6C.
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Affiliation(s)
- K Dahl
- Department of Chemistry, Penn State University, University Park, PA 16802, USA
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The lifetime of the perpendicular minimum of cis-stilbene observed by dissociative intense-laser field ionization. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2003.12.114] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fuss W, Rettig W, Schmid WE, Trushin SA, Yatsuhashi T. Ultrafast temporary charge transfer in pyrrolidinyl–benzonitrile and pyrrolyl–benzonitrile in the gas phase. Faraday Discuss 2004; 127:23-33. [PMID: 15471337 DOI: 10.1039/b313691d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
4-(N-pyrrolidinyl)benzonitrile and 4-(N-pyrrolyl)benzonitrile were excited by an ultrashort pulse at 270 nm to their La (S2) states and then probed by ionization at long wavelengths. Parent and fragment ion signals show components with time constants < 100 fs which we attribute to ultrafast relaxation to the Lb (S1) state. From this short time we infer a conical intersection between the Lb and La surfaces. The wave packet can branch there, one part going temporarily to a strongly displaced state. Its shift was concluded from an anisotropy observed only there. The only excited state known to have a large displacement is the charge-transfer (CT) state. The positive anisotropy indicates that the CT state belongs to the 2A species for both molecules. For pyrrolylbenzonitrile, this is in contrast to previous assignments. The anisotropy, and a coherent oscillation observed in pyrrolidinylbenzonitrile, support the idea that the amino-group twist is an important component of the CT reaction coordinate.
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Affiliation(s)
- Werner Fuss
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
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