1
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Changala PB, McCarthy MC. Rotational Spectrum of the Phenoxy Radical. J Phys Chem Lett 2024:5063-5069. [PMID: 38701387 DOI: 10.1021/acs.jpclett.4c00962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
We report the hyperfine-resolved rotational spectrum of the gas-phase phenoxy radical in the 8-25 GHz frequency range using cavity Fourier transform microwave spectroscopy. A complete assignment of its complex but well-resolved fine and hyperfine splittings yielded a precisely determined set of rotational constants, spin-rotation parameters, and nuclear hyperfine coupling constants. These results are interpreted with support from high-level quantum chemical calculations to gain detailed insight into the distribution of the unpaired π electron in this prototypical resonance-stabilized radical. The accurate laboratory rest frequencies enable studies of the chemistry of phenoxy in both the laboratory and space. The prospects of extending the present experimental and theoretical techniques to investigate the rotational spectra of isotopic variants and structural isomers of phenoxy and other important gas-phase radical intermediates that are yet undetected at radio wavelengths are discussed.
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Affiliation(s)
- P Bryan Changala
- Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, United States
| | - Michael C McCarthy
- Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, United States
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2
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Opoku E, Pawłowski F, Ortiz JV. New-generation electron-propagator methods for vertical electron detachment energies of molecular anions: benchmarks and applications to model green-fluorescent-protein chromophores. Phys Chem Chem Phys 2024; 26:9915-9930. [PMID: 38482723 DOI: 10.1039/d4cp00441h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Ab initio electron-propagator calculations continue to be useful companions to experimental investigations of electronic structure in molecular anions. A new generation of electron-propagator methods recently has surpassed its antecedents' predictive accuracy and computational efficiency. Interpretive clarity has been conserved, for no adjustable parameters have been introduced in the preparation of molecular orbitals or in the formulation of approximate self-energies. These methods have employed the diagonal self-energy approximation wherein each Dyson orbital equals a canonical Hartree-Fock orbital times the square root of a probability factor. Numerical tests indicate that explicitly renormalized, diagonal self-energies are needed when Dyson orbitals have large valence nitrogen, oxygen or fluorine components. They also demonstrate that even greater accuracy can be realized with generalizations that do not employ the diagonal self-energy approximation in the canonical Hartree-Fock basis. Whereas the diagonal methods have fifth-power arithmetic scaling factors, the non-diagonal generalizations introduce only non-iterative sixth-power contractions. Composite models conserve the accuracy of the most demanding combinations of self-energy approximations and flexible basis sets with drastically reduced computational effort. Composite-model results on anions that resemble the chromophore of the green fluorescent protein illustrate the interpretive capabilities of explicitly renormalized self-energies. Accurate predictions on the lowest vertical electron detachment energy of each anion confirm experimental data and the utility of the diagonal self-energy approximation.
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Affiliation(s)
- Ernest Opoku
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Filip Pawłowski
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - J V Ortiz
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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3
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Zhang YR, Yuan DF, Wang LS. Probing Dipole-Bound States Using Photodetachment Spectroscopy and Resonant Photoelectron Imaging of Cryogenically Cooled Anions. J Phys Chem Lett 2023; 14:7368-7381. [PMID: 37565830 DOI: 10.1021/acs.jpclett.3c01994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Molecular anions with polar neutral cores can support highly diffuse dipole-bound states below their detachment thresholds due to the long-range charge-dipole interaction. Such nonvalence states constitute a special class of excited electronic states for anions and were observed in early photodetachment experiments to measure the electron affinities of organic radicals. Recent experimental advances, in particular, the ability to create cold anions using a cryogenically cooled Paul trap, have allowed the investigation of dipole-bound excited states at a new level. For the first time, the zero-point level of dipole-bound excited states can be observed via resonant two-photon detachment, and resonant photoelectron spectroscopy can be performed via the above-threshold vibrational levels (Feshbach resonances) of the dipole-bound states. This Perspective describes recent progress in the investigation of dipole-bound states in the authors' lab using an electrospray photoelectron spectroscopy apparatus equipped with a cryogenically cooled Paul trap and high-resolution photoelectron imaging.
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Affiliation(s)
- Yue-Rou Zhang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Dao-Fu Yuan
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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4
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Kim J, Woo KC, Kim KK, Kim SK. πσ*-Mediated Nonadiabatic Tunneling Dynamics of Thiophenols in S 1: The Semiclassical Approaches. J Phys Chem A 2022; 126:9594-9604. [PMID: 36534791 DOI: 10.1021/acs.jpca.2c05861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The S-H bond tunneling predissociation dynamics of thiophenol and its ortho-substituted derivatives (2-fluorothiophenol, 2-methoxythiophenol, and 2-chlorothiphenol) in S1 (ππ*) where the H atom tunneling is mediated by the nearby S2 (πσ*) state (which is repulsive along the S-H bond extension coordinate) have been investigated in a state-specific way using the picosecond time-resolved pump-probe spectroscopy for the jet-cooled molecules. The effects of the specific vibrational mode excitations and the SH/SD substitutions on the S-H(D) bond rupture tunneling dynamics have been interrogated, giving deep insights into the multidimensional aspects of the S1/S2 conical intersection, which also shapes the underlying adiabatic tunneling potential energy surfaces (PESs). The semiclassical tunneling rate calculations based on the Wentzel-Kramers-Brillouin (WKB) approximation or Zhu-Nakamura (ZN) theory have been carried out based on the ab initio PESs calculated in the (one, two, or three) reduced dimensions to be compared with the experiment. Though the quantitative experimental results could not be reproduced satisfactorily by the present calculations, the qualitative trends among different molecules in terms of the behavior of the tunneling rate versus the (adiabatic) barrier height or the number of PES dimensions could be rationalized. Most interestingly, the H/D kinetic isotope effect observed in the tunneling rate could be much better explained by the ZN theory compared to the WKB approximation, indicating that the nonadiabatic coupling matrix elements should be invoked for understanding the tunneling dynamics taking place in the proximity of the conical intersection.
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Affiliation(s)
- Junggil Kim
- Department of Chemistry, KAIST, Daejeon34141, Republic of Korea
| | - Kyung Chul Woo
- Department of Chemistry, KAIST, Daejeon34141, Republic of Korea
| | - Kuk Ki Kim
- Department of Chemistry, KAIST, Daejeon34141, Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon34141, Republic of Korea
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5
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Kim J, Woo KC, Kim KK, Kang M, Kim SK. Tunneling dynamics dictated by the multidimensional conical intersection seam in the πσ*‐mediated photochemistry of heteroaromatic molecules. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Junggil Kim
- Department of Chemistry, KAIST Daejeon Republic of Korea
| | - Kyung Chul Woo
- Department of Chemistry, KAIST Daejeon Republic of Korea
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences Nanyang Technological University Singapore Singapore
| | - Kuk Ki Kim
- Department of Chemistry, KAIST Daejeon Republic of Korea
| | - Minseok Kang
- Department of Chemistry, KAIST Daejeon Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST Daejeon Republic of Korea
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6
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Bin Mohd Yusof MS, Lim YL, Loh ZH. Ultrafast vibrational wave packet dynamics of the aqueous tyrosyl radical anion induced by photodetachment. Phys Chem Chem Phys 2021; 23:18525-18534. [PMID: 34581329 DOI: 10.1039/d1cp02975d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ultrafast dynamics triggered by the photodetachment of the tyrosinate dianion in aqueous environment shed light on the elementary processes that accompany the interaction of ionizing radiation with biological matter. Photodetachment of the tryosinate dianion yields the tyrosyl radical anion, an important intermediate in biological redox reactions, although the study of its ultrafast dynamics is limited. Here, we utilize femtosecond optical pump-probe spectroscopy to investigate the ultrafast structural reorganization dynamics that follow the photodetachment of the tyrosinate dianion in aqueous solution. Photodetachment of the tyrosinate dianion leads to vibrational wave packet motion along seven vibrational modes that are coupled to the photodetachment process. The vibrational modes are assigned with the aid of density functional theory (DFT) calculations. Our results offer a glimpse of the elementary dynamics of ionized biomolecules and suggest the possibility of extending this approach to investigate the ionization-induced structural rearrangement of other aromatic amino acids and larger biomolecules.
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Affiliation(s)
- Muhammad Shafiq Bin Mohd Yusof
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Yong Liang Lim
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
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7
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Chou S, Lin S, Chen H, Wu Y. Infrared absorption spectra of phenoxide anions isolated in solid argon. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202100223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sheng‐Lung Chou
- Scientific Research Division National Synchrotron Radiation Research Center Hsinchu Taiwan
| | - Shu‐Yu Lin
- Scientific Research Division National Synchrotron Radiation Research Center Hsinchu Taiwan
- Department of Applied Chemistry National Yang Ming Chiao Tung University Hsinchu Taiwan
| | - Hui‐Fen Chen
- Department of Medicinal and Applied Chemistry Kaohsiung Medical University Kaohsiung Taiwan
| | - Yu‐Jong Wu
- Scientific Research Division National Synchrotron Radiation Research Center Hsinchu Taiwan
- Department of Applied Chemistry National Yang Ming Chiao Tung University Hsinchu Taiwan
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8
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Qian CH, Zhang YR, Yuan DF, Wang LS. Photodetachment spectroscopy and resonant photoelectron imaging of cryogenically cooled 1-pyrenolate. J Chem Phys 2021; 154:094308. [PMID: 33685163 DOI: 10.1063/5.0043932] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We report an investigation of the 1-pyrenolate anion (PyO-) and the 1-pyrenoxy radical (PyO) using photodetachment spectroscopy and resonant photoelectron imaging of cryogenically cooled anions. The electron affinity of PyO is measured to be 2.4772(4) eV (19 980 ± 3 cm-1) from high-resolution photoelectron spectroscopy. Photodetachment spectroscopy reveals a dipole-bound state (DBS) for PyO- 280 cm-1 below the detachment threshold as well as a broad and intense valence excited state (shape resonance) 1077 cm-1 above the detachment threshold. The shape resonance with an excitation energy of 21 055 cm-1 is due to excitation of an electron from the highest occupied molecular orbital of PyO- to its lowest unoccupied molecular orbital in the continuum. Twenty-nine vibrational levels of the DBS are observed, including 27 above-threshold vibrational levels (vibrational Feshbach resonances). Twenty-seven resonant photoelectron spectra are obtained by tuning the detachment laser to the vibrational Feshbach resonances, resulting in highly non-Franck-Condon photoelectron spectra and rich vibrational information. In total, the frequencies of 21 vibrational modes are obtained for the PyO radical by the combination of the photodetachment and resonant photoelectron spectroscopy, including 13 out-of-plane bending modes.
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Affiliation(s)
- Chen-Hui Qian
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Yue-Rou Zhang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Dao-Fu Yuan
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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9
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Simons J. Ejecting Electrons from Molecular Anions via Shine, Shake/Rattle, and Roll. J Phys Chem A 2020; 124:8778-8797. [DOI: 10.1021/acs.jpca.0c08016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jack Simons
- Henry Eyring Center for Theoretical Chemistry, Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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10
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Kang DH, An S, Kim SK. Real-Time Autodetachment Dynamics of Vibrational Feshbach Resonances in a Dipole-Bound State. PHYSICAL REVIEW LETTERS 2020; 125:093001. [PMID: 32915603 DOI: 10.1103/physrevlett.125.093001] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/13/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
Feshbach resonances corresponding to metastable vibrational states of the dipole-bound state (DBS) have been interrogated in real time for the first time. The state-specific autodetachment rates of the DBS of the phenoxide anion in the cryogenically cooled ion trap have been directly measured, giving τ∼33.5 ps for the lifetime of the most prominent 11^{'1} mode (519 cm^{-1}). Overall, the lifetime of the individual DBS state is strongly mode dependent to give τ∼5 ps for the 18^{'1} mode (632 cm^{-1}) and τ∼12 ps for the 11^{'2} mode (1036 cm^{-1}). The qualitative trend of the experiment could be successfully explained by the Fermi's golden rule. Autodetachment of the 11^{'1}18^{'1} combination mode is found to be much accelerated (τ≤1.4 ps) than expected, and its bifurcation dynamics into either the 11^{1}18^{0} or 11^{0}18^{1} state of the neutral core radical, according to the propensity rule of Δv=-1, could be distinctly differentiated through the photoelectron images to provide the unprecedented deep insights into the interaction between electronic and nuclear dynamics of the DBS, challenging the most sophisticated theoretical calculations.
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Affiliation(s)
- Do Hyung Kang
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Sejun An
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
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11
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Yuan Q, Cao W, Hetzert M, Ruschewitz U, Wang XB. Velocity-Map Imaging and Magnetic-Bottle Photoelectron Spectroscopy of [SeCCH] -: Electronic Properties and Spin-Orbit Splitting. J Phys Chem A 2020; 124:3214-3219. [PMID: 32250629 DOI: 10.1021/acs.jpca.0c01936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The recently synthesized acetylide compound KSeCCH containing the main group element selenium within the novel and in crystalline form unprecedented [SeCCH]- anion was successfully investigated in the gas phase by high-resolution velocity-map imaging (VMI) and magnetic-bottle (MB) photoelectron spectroscopy coupled with an electrospray ionization source. Both VMI and MB spectra exhibited identical electron affinities (EA, 2.517 ± 0.002 eV), spin-orbit coupling (SOC) splittings (1492 ± 20 cm-1), and Se-C stretching frequencies (573 ± 20 cm-1) of the corresponding neutral tetra-atomic radical [SeCCH]• with the VMI spectrum possessing six times higher spectral resolution compared with the MB spectrum. These experimental values were well reproduced by calculations at the CCSD(T) level, in which both the isolated [SeCCH]- anion and the [SeCCH]• radical adopted linear geometries. The simulated spectra based on the calculated Franck-Condon factors, the SOC splitting, and the experimental line width matched well with the measured spectra. Furthermore, comparisons of the EA and SOC splitting values with the previously reported isolobal species [SeCN]• are also made and discussed. The decrease in the EA and SOC splitting of [SeCCH]• is ascribed to the differences in the electronegativities between C and N atoms as well as the electron density on the Se atom in its singly occupied molecular orbital (SOMO).
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Affiliation(s)
- Qinqin Yuan
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Wenjin Cao
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Marc Hetzert
- Department of Chemistry, University of Cologne, Greinstrasse 6, 50939 Köln, Germany
| | - Uwe Ruschewitz
- Department of Chemistry, University of Cologne, Greinstrasse 6, 50939 Köln, Germany
| | - Xue-Bin Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
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12
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Blackshaw KJ, Marracci M, Korb RT, Quartey NK, Ajmani AK, Hood DJ, Abelt CJ, Ortega BI, Luong K, Petit AS, Kidwell NM. Dynamical signatures from competing, nonadiabatic fragmentation pathways of S-nitrosothiophenol. Phys Chem Chem Phys 2020; 22:12187-12199. [DOI: 10.1039/d0cp00941e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A joint experiment-theory study of the UV photolysis of S-nitrosothiophenol reveals competing photodissociation pathways that produce NO in its spin–orbit ground state and thiophenoxy radical in either its ground or excited electronic state.
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Affiliation(s)
| | - Marcus Marracci
- Department of Chemistry and Biochemistry
- California State University – Fullerton
- Fullerton
- USA
| | - Robert T. Korb
- Department of Chemistry
- The College of William and Mary
- Williamsburg
- USA
| | | | | | - David J. Hood
- Department of Chemistry
- The College of William and Mary
- Williamsburg
- USA
| | | | - Belinda I. Ortega
- Department of Chemistry and Biochemistry
- California State University – Fullerton
- Fullerton
- USA
| | - Kate Luong
- Department of Chemistry and Biochemistry
- California State University – Fullerton
- Fullerton
- USA
| | - Andrew S. Petit
- Department of Chemistry and Biochemistry
- California State University – Fullerton
- Fullerton
- USA
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13
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Lim JS, You HS, Kim SY, Kim J, Park YC, Kim SK. Vibronic structure and predissociation dynamics of 2-methoxythiophenol (S 1): The effect of intramolecular hydrogen bonding on nonadiabatic dynamics. J Chem Phys 2019; 151:244305. [PMID: 31893886 DOI: 10.1063/1.5134519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Vibronic spectroscopy and the S-H bond predissociation dynamics of 2-methoxythiophenol (2-MTP) in the S1 (ππ*) state have been investigated for the first time. Resonant two-photon ionization and slow-electron velocity map imaging (SEVI) spectroscopies have revealed that the S1-S0 transition of 2-MTP is accompanied with the planar to the pseudoplanar structural change along the out-of-plane ring distortion and the tilt of the methoxy moiety. The S1 vibronic bands up to their internal energy of ∼1000 cm-1 are assigned from the SEVI spectra taken via various S1 vibronic intermediate states with the aid of ab initio calculations. Intriguingly, Fermi resonances have been identified for some vibronic bands. The S-H bond breakage of 2-MTP occurs via tunneling through an adiabatic barrier under the S1/S2 conical intersection seam, and it is followed by the bifurcation into either the adiabatic or nonadiabatic channel at the S0/S2 conical intersection where the diabatic S2 state (πσ*) is unbound with respect to the S-H bond elongation coordinate, giving the excited (Ã) or ground (X̃) state of the 2-methoxythiophenoxy radical, respectively. Surprisingly, the nonadiabatic transition probability at the S0/S2 conical intersection, estimated from the velocity map ion images of the nascent D fragment from 2-MTP-d1 (2-CH3O-C6H4SD) at the S1 zero-point energy level, is found to be exceptionally high to give the X̃/Ã product branching ratio of 2.03 ± 0.20, which is much higher than the value of ∼0.8 estimated for the bare thiophenol at the S1 origin. It even increases to 2.33 ± 0.17 at the ν45 2 mode (101 cm-1) before it rapidly decays to 0.69 ± 0.05 at the S1 internal energy of about 2200 cm-1. This suggests that the strong intramolecular hydrogen bonding of S⋯D⋯OCH3 in 2-MTP at least in the low S1 internal energy region should play a significant role in localizing the reactive flux onto the conical intersection seam. The minimum energy pathway calculations (second-order coupled-cluster resolution of the identity or time-dependent-density functional theory) of the adiabatic S1 state suggest that the intimate dynamic interplay between the S-H bond cleavage and intramolecular hydrogen bonding could be crucial in the nonadiabatic surface hopping dynamics taking place at the conical intersection.
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Affiliation(s)
- Jean Sun Lim
- Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Hyun Sik You
- Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - So-Yeon Kim
- Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Junggil Kim
- Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | | | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 34141, South Korea
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14
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Qian CH, Zhu GZ, Wang LS. Probing the Critical Dipole Moment To Support Excited Dipole-Bound States in Valence-Bound Anions. J Phys Chem Lett 2019; 10:6472-6477. [PMID: 31589447 DOI: 10.1021/acs.jpclett.9b02679] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report photodetachment spectroscopy and high-resolution photoelectron imaging of para-halogen substituted phenoxide anions, p-XC6H4O- (X = F, Cl, Br, I). The dipole moments of the p-XC6H4O neutral radicals increase from 2.56 to 3.19 D for X = F to I, providing a series of similar molecules to allow the examination of charge-dipole interactions by minimizing molecule-dependent effects. Excited DBSs ([XC6H4O]*-) are observed for the four anions with binding energies of 8, 11, 24, and 53 cm-1, respectively, for X = F to I, below their respective detachment thresholds. The binding energies exhibit a linear correlation with the dipole moments of the neutral radicals, extrapolating to a critical dipole moment of 2.5 D for zero binding energy. Because of the small binding energy of the excited DBS of [FC6H4O]*-, rotational autodetachment is observed to compete with vibrational autodetachment in the resonant photoelectron spectra, resulting in electrons with near zero kinetic energies.
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Affiliation(s)
- Chen-Hui Qian
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , United States
| | - Guo-Zhu Zhu
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , United States
| | - Lai-Sheng Wang
- Department of Chemistry , Brown University , Providence , Rhode Island 02912 , United States
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15
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Zhu GZ, Wang LS. High-resolution photoelectron imaging and resonant photoelectron spectroscopy via noncovalently bound excited states of cryogenically cooled anions. Chem Sci 2019; 10:9409-9423. [PMID: 32055317 PMCID: PMC6984392 DOI: 10.1039/c9sc03861b] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 09/16/2019] [Indexed: 01/12/2023] Open
Abstract
Valence-bound anions with polar neutral cores (μ > ∼2.5 D) can support dipole-bound excited states below the detachment threshold. These dipole-bound states (DBSs) are highly diffuse and the weakly bound electron in the DBS can be readily autodetached via vibronic coupling. Excited DBSs can be observed in photodetachment spectroscopy using a tunable laser. Tuning the detachment laser to above-threshold vibrational resonances yields vibrationally enhanced resonant photoelectron spectra, which are highly non-Franck-Condon with much richer vibrational information. This perspective describes recent advances in the studies of excited DBSs of cryogenically cooled anions using high-resolution photoelectron imaging (PEI) and resonant photoelectron spectroscopy (rPES). The basic features of dipole-bound excited states and highly non-Franck-Condon resonant photoelectron spectra will be discussed. The power of rPES to yield rich vibrational information beyond conventional PES will be highlighted, especially for low-frequency and Franck-Condon-inactive vibrational modes, which are otherwise not accessible from non-resonant conventional PES. Mode-selectivity and intra-molecular rescattering have been observed during the vibrationally induced autodetachment. Conformer-specific rPES is possible due to the different dipole-bound excited states of molecular conformers with polar neutral cores. For molecules with μ ≪ 2.5 D or without dipole moments, but large quadrupole moments, excited quadrupole-bound states can exist, which can also be used to conduct rPES.
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Affiliation(s)
- Guo-Zhu Zhu
- Department of Chemistry , Brown University , Providence , RI 02912 , USA .
| | - Lai-Sheng Wang
- Department of Chemistry , Brown University , Providence , RI 02912 , USA .
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16
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Panja SK, Verma S, Saha S. Probing phenol dimer in molecular complex: Role of nitro group and stabilizing agent. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Ultrafast structural rearrangement dynamics induced by the photodetachment of phenoxide in aqueous solution. Nat Commun 2019; 10:2944. [PMID: 31270331 PMCID: PMC6610110 DOI: 10.1038/s41467-019-10989-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/14/2019] [Indexed: 01/28/2023] Open
Abstract
The elementary processes that accompany the interaction of ionizing radiation with biologically relevant molecules are of fundamental importance. However, the ultrafast structural rearrangement dynamics induced by the ionization of biomolecules in aqueous solution remain hitherto unknown. Here, we employ femtosecond optical pump-probe spectroscopy to elucidate the vibrational wave packet dynamics that follow the photodetachment of phenoxide, a structural mimic of tyrosine, in aqueous solution. Photodetachment of phenoxide leads to wave packet dynamics of the phenoxyl radical along 12 different vibrational modes. Eight of the modes are totally symmetric and support structural rearrangement upon electron ejection. Comparison to a previous photodetachment study of phenoxide in the gas phase reveals the important role played by the solvent environment in driving ultrafast structural reorganization induced by ionizing radiation. This work provides insight into the ultrafast molecular dynamics that follow the interaction of ionizing radiation with molecules in aqueous solution. The interaction of biomolecules with ionizing radiation induces structural changes which are still largely unknown. The authors use femtosecond wave packet spectroscopy to observe ultrafast structural dynamics that follow the photodetachment of phenoxide in aqueous solution.
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18
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Sullivan EN, Nichols B, Neumark DM. Fast beam photofragment translational spectroscopy of the phenoxy radical at 225 nm, 290 nm, and 533 nm. Phys Chem Chem Phys 2019; 21:14270-14277. [PMID: 30566134 DOI: 10.1039/c8cp06818f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photodissociation of the phenoxy radical (C6H5O) is investigated using fast beam photofragment translational spectroscopy. Phenoxy radicals are generated through photodetachment of phenoxide anions (C6H5O-) at 532 nm. Following photoexcitation of the radicals at 225 nm (5.51 eV), 290 nm (4.27 eV), or 533 nm (2.33 eV), photofragments are collected in coincidence to determine their masses, translational energy, and scattering angle for each dissociation event. Two-body dissociation yields exclusively CO + C5H5, and three-body dissociation to CO + C2H2 + C3H3 and CO + C5H4 + H is also seen at the two higher energies. The translational energy distributions for two-body dissociation suggest that dissociation occurs via internal conversion to the ground electronic state followed by statistical dissociation. The absorption of an additional 532 nm photon in the photodetachment region provides some C6H5O radicals with an additional 2.33 eV of energy, leading to much of the two-body dissociation observed at 533 nm and the three-body dissociation at the two higher excitation energies.
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Affiliation(s)
- Erin N Sullivan
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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19
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Woodhouse JL, Henley A, Parkes MA, Fielding HH. Photoelectron Imaging and Quantum Chemistry Study of Phenolate, Difluorophenolate, and Dimethoxyphenolate Anions. J Phys Chem A 2019; 123:2709-2718. [PMID: 30848907 DOI: 10.1021/acs.jpca.8b11121] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joanne L. Woodhouse
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AH, U.K
| | - Alice Henley
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AH, U.K
| | - Michael A. Parkes
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AH, U.K
| | - Helen H. Fielding
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AH, U.K
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20
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Lim JS, You HS, Kim SY, Kim SK. Experimental observation of nonadiabatic bifurcation dynamics at resonances in the continuum. Chem Sci 2019; 10:2404-2412. [PMID: 30881669 PMCID: PMC6385646 DOI: 10.1039/c8sc04859b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/04/2019] [Indexed: 11/23/2022] Open
Abstract
The surface crossing of bound and unbound electronic states in multidimensional space often gives rise to resonances in the continuum. This situation happens in the πσ*-mediated photodissociation reaction of 2-fluorothioanisole; optically-bright bound S1 (ππ*) vibrational states of 2-fluorothioanisole are strongly coupled to the optically-dark S2 (πσ*) state, which is repulsive along the S-CH3 elongation coordinate. It is revealed here that the reactive flux prepared at such resonances in the continuum bifurcates into two distinct reaction pathways with totally different dynamics in terms of energy disposal and nonadiabatic transition probability. This indicates that the reactive flux in the Franck-Condon region may either undergo nonadiabatic transition funneling through the conical intersection from the upper adiabat, or follow a low-lying adiabatic path, along which multiple dynamic saddle points may be located. Since 2-fluorothioanisole adopts a nonplanar geometry in the S1 minimum energy, the quasi-degenerate S1/S2 crossing seam in the nonplanar geometry, which lies well below the planar S1/S2 conical intersection, is likely responsible for the efficient vibronic coupling, especially in the low S1 internal energy region. As the excitation energy increases, bound-to-continuum coupling is facilitated with the aid of intramolecular vibrational redistribution, along many degrees of freedom spanning the large structural volume. This leads to the rapid domination of the continuum character of the reactive flux. This work reports direct and robust experimental observations of the nonadiabatic bifurcation dynamics of the reactive flux occurring at resonances in the continuum of polyatomic molecules.
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Affiliation(s)
- Jean Sun Lim
- Department of Chemistry , KAIST , Daejeon 34141 , Republic of Korea .
| | - Hyun Sik You
- Department of Chemistry , KAIST , Daejeon 34141 , Republic of Korea .
| | - So-Yeon Kim
- Department of Chemistry , KAIST , Daejeon 34141 , Republic of Korea .
| | - Sang Kyu Kim
- Department of Chemistry , KAIST , Daejeon 34141 , Republic of Korea .
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21
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Noble JA, Aranguren-Abate JP, Dedonder C, Jouvet C, Pino GA. Photodetachment of deprotonated aromatic amino acids: stability of the dehydrogenated radical depends on the deprotonation site. Phys Chem Chem Phys 2019; 21:23346-23354. [DOI: 10.1039/c9cp04302k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
When aromatic amino acids are deprotonated on the carbonyl, the radicals produced upon photodetachment dissociate without barrier, forming CO2 and a radical amine. When the functional group on the chromophore is deprotonated, the radicals are stable.
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Affiliation(s)
- Jennifer Anna Noble
- PIIM
- UMR-CNRS 7345
- Aix-Marseille Univ. Avenue
- Escadrille Normandie-Niémen
- 13397 Marseille Cedex 20
| | - Juan P. Aranguren-Abate
- INFIQC
- Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET – UNC)
- Haya de la Torre y Medina Allende
- Ciudad Universitaria
- X5000HUA Córdoba
| | - Claude Dedonder
- PIIM
- UMR-CNRS 7345
- Aix-Marseille Univ. Avenue
- Escadrille Normandie-Niémen
- 13397 Marseille Cedex 20
| | - Christophe Jouvet
- PIIM
- UMR-CNRS 7345
- Aix-Marseille Univ. Avenue
- Escadrille Normandie-Niémen
- 13397 Marseille Cedex 20
| | - Gustavo A. Pino
- Departamento de Fisicoquímica
- Facultad de Ciencias Químicas
- Universidad Nacional de Córdoba
- Haya de la Torre y Medina Allende
- Ciudad Universitaria
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22
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Wong NGK, Berenbeim JA, Hawkridge M, Matthews E, Dessent CEH. Mapping the intrinsic absorption properties and photodegradation pathways of the protonated and deprotonated forms of the sunscreen oxybenzone. Phys Chem Chem Phys 2019; 21:14311-14321. [PMID: 30680382 DOI: 10.1039/c8cp06794e] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sunscreens provide vital protection against the photodamaging effects of UV radiation, however, many fundamental questions remain about the detailed mechanisms by which they dissipate UV energy. One such issue is the extent to which the pH environment of an organic sunscreen molecule alters its effectiveness, both in terms of ability to absorb UV radiation, and also its potential to photodegrade. Here, we use gas-phase laser photodissociation spectroscopy for the first time to measure the intrinsic UVA-UVC absorption spectra and associated photodegradation products of protonated and deprotonated oxybenzone, away from the complications of bulk mixtures. Our results reveal that protonation state has a dramatic effect on the absorption and photodissociation properties of this sunscreen. While the UV absorption profile of oxybenzone is only modestly affected by protonation across the range from 400-216 nm, deprotonated oxybenzone displays a significantly modified absorption spectrum, with very low photoabsorption between 370-330 nm. Protonated oxybenzone primarily photofragments by rupture of the bonds on either side of the central carbonyl group, producing cationic fragments with m/z 151 and 105. Additional lower mass photofragments (e.g. m/z 95 and 77) are also observed. The production spectra for the photofragments from protonated oxybenzone fall into two distinct categories, which we discuss in the context of different excited state decay pathways. For deprotonated oxybenzone, the major photofragments observed are m/z 211 and 212, which are associated with the ejection of methane and the methyl free radical from the parent ion, respectively. Implications for the suitability of oxybenzone in its protonated and deprotonated forms as an optimum sunscreen molecule are discussed.
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Affiliation(s)
- Natalie G K Wong
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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23
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Zhu GZ, Qian CH, Wang LS. Dipole-bound excited states and resonant photoelectron imaging of phenoxide and thiophenoxide anions. J Chem Phys 2018; 149:164301. [DOI: 10.1063/1.5049715] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Guo-Zhu Zhu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Chen-Hui Qian
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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24
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Kregel SJ, Garand E. Ground and low-lying excited states of phenoxy, 1-naphthoxy, and 2-naphthoxy radicals via anion photoelectron spectroscopy. J Chem Phys 2018; 149:074309. [DOI: 10.1063/1.5045685] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Steven J. Kregel
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
| | - Etienne Garand
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
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25
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Yuan QQ, Yang Z, Li RZ, Transue WJ, Li ZP, Jiang L, Govind N, Cummins CC, Wang XB. Magnetic-Bottle and velocity-map imaging photoelectron spectroscopy of APS− (A=C14H10 or anthracene): Electron structure, spin-orbit coupling of APS•, and dipole-bound state of APS−. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1805114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Qin-qin Yuan
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P. O. Box 999, MS K8-88, Richland, Washington 99352, USA
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng Yang
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P. O. Box 999, MS K8-88, Richland, Washington 99352, USA
| | - Ren-zhong Li
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P. O. Box 999, MS K8-88, Richland, Washington 99352, USA
| | - Wesley J. Transue
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Zhi-peng Li
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P. O. Box 999, MS K8-88, Richland, Washington 99352, USA
| | - Ling Jiang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Niranjan Govind
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P. O. Box 999, MS K8-91, Richland WA 99352, USA
| | - Christopher C. Cummins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xue-Bin Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P. O. Box 999, MS K8-88, Richland, Washington 99352, USA
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26
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Ormond TK, Baraban JH, Porterfield JP, Scheer AM, Hemberger P, Troy TP, Ahmed M, Nimlos MR, Robichaud DJ, Daily JW, Ellison GB. Thermal Decompositions of the Lignin Model Compounds: Salicylaldehyde and Catechol. J Phys Chem A 2018; 122:5911-5924. [DOI: 10.1021/acs.jpca.8b03201] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Thomas K. Ormond
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Joshua H. Baraban
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Jessica P. Porterfield
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Adam M. Scheer
- Combustion Research Facility, Sandia National Laboratory, PO Box 969, Livermore, California 94551-0969, United States
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, CH-5234 Villigen-PSI, Switzerland
| | - Tyler P. Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Mark R. Nimlos
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - David J. Robichaud
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - John W. Daily
- Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309-0427, United States
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
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27
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Yang Z, Hrovat DA, Hou GL, Borden WT, Wang XB. Negative Ion Photoelectron Spectroscopy Confirms the Prediction of the Relative Energies of the Low-Lying Electronic States of 2,7-Naphthoquinone. J Phys Chem A 2018; 122:4838-4844. [PMID: 29745661 DOI: 10.1021/acs.jpca.8b03239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cryogenic negative ion photoelectron (NIPE) spectra of the radical anion of 2,7-naphthoquinone (NQ•-) have been taken at 20 K, using 193, 240, 266, 300, and 355 nm lasers for electron detachment. The electron affinity of the NQ diradical is determined from the first resolved peak in the NIPE spectrum to be 2.880 ± 0.010 eV. CASPT2/aug-cc-pVDZ calculations predict with reasonable accuracy the positions of the 0-0 bands in the three lowest electronic states of NQ. In addition, the Franck-Condon factors calculated from the CASPT2/aug-cc-pVDZ optimized geometries, vibrational frequencies, and normal modes successfully simulate the vibrational structures in these bands. The NIPE spectrum of NQ•- confirms that, as predicted, 3B2 is the ground state, and the 1B2 and 1A1 states are, respectively, 12.7 and 16.4 kcal/mol higher in energy than the triplet ground state. The experimental value of Δ EST = 12.7 kcal/mol in NQ and the finding that 1B2 is the lower energy of the two singlet states confirm the results of the previous calculations on NQ. These calculations predicted an increase in Δ EST on the substitution of both methylene groups in 2,7-naphthoquinodimethane (NQDM) by oxygens in NQ, thus providing a dramatic contrast to the decrease of 17.5 kcal/mol in Δ EST found for substitution of one methylene group by one oxygen on going from trimethylenemethane (TMM) to oxyallyl (OXA).
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Affiliation(s)
- Zheng Yang
- Physical Sciences Division , Pacific Northwest National Laboratory , P.O. Box 999, MS K8-88, Richland , Washington 99352 , United States
| | - David A Hrovat
- Department of Chemistry and the Center for Advanced, Scientific Computing and Modeling , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5070 , United States
| | - Gao-Lei Hou
- Physical Sciences Division , Pacific Northwest National Laboratory , P.O. Box 999, MS K8-88, Richland , Washington 99352 , United States
| | - Weston Thatcher Borden
- Department of Chemistry and the Center for Advanced, Scientific Computing and Modeling , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5070 , United States
| | - Xue-Bin Wang
- Physical Sciences Division , Pacific Northwest National Laboratory , P.O. Box 999, MS K8-88, Richland , Washington 99352 , United States
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28
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Woo KC, Kang DH, Kim SK. Real-Time Observation of Nonadiabatic Bifurcation Dynamics at a Conical Intersection. J Am Chem Soc 2017; 139:17152-17158. [DOI: 10.1021/jacs.7b09677] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kyung Chul Woo
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Do Hyung Kang
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
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29
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Marchetti B, Karsili TNV, Cipriani M, Hansen CS, Ashfold MNR. The near ultraviolet photodissociation dynamics of 2- and 3-substituted thiophenols: Geometric vs. electronic structure effects. J Chem Phys 2017; 147:013923. [DOI: 10.1063/1.4980035] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Hou GL, Chen B, Transue WJ, Yang Z, Grützmacher H, Driess M, Cummins CC, Borden WT, Wang XB. Spectroscopic Characterization, Computational Investigation, and Comparisons of ECX– (E = As, P, and N; X = S and O) Anions. J Am Chem Soc 2017; 139:8922-8930. [DOI: 10.1021/jacs.7b02984] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Gao-Lei Hou
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Bo Chen
- Baker
Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Wesley J. Transue
- Department
of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Zheng Yang
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Hansjörg Grützmacher
- Department
of Chemistry and Applied Biology, ETH-Hönggerberg, 8093 Zürich, Switzerland
| | - Matthias Driess
- Department
of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin, Germany
| | - Christopher C. Cummins
- Department
of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Weston Thatcher Borden
- Department
of Chemistry and the Center for Advanced Scientific Computing and
Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
| | - Xue-Bin Wang
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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31
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Nelson DJ, Gichuhi WK, Miller EM, Lehman JH, Lineberger WC. Anion photoelectron spectroscopy of deprotonatedortho-,meta-, andpara-methylphenol. J Chem Phys 2017; 146:074302. [DOI: 10.1063/1.4975330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel J. Nelson
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Wilson K. Gichuhi
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Elisa M. Miller
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Julia H. Lehman
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - W. Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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32
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Fulara J, Erattupuzha S, Garkusha I, Maier JP. Structure and Electronic Transitions of C 7H 4O 2+ and C 7H 5O 2+ Ions: Neon Matrix and Theoretical Studies. J Phys Chem A 2016; 120:10134-10140. [PMID: 27976905 DOI: 10.1021/acs.jpca.6b10687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
C7H4O2+ and C7H5O2+ ions and the respective neutrals have been investigated by absorption spectroscopy in neon matrixes following mass selection of ions produced from salicylic acid. Three electronic transitions starting at 649.6, 431.0, and 372.0 nm are detected for C7H4O2+ and assigned on the basis of CASPT2 energies and Franck-Condon simulations as the excitations from the X 2A″ to the 1 2A″, 2 2A″, and 3 2A″ electronic states of 6-(oxomethylene)-2,4-cyclohexadien-1-one ion (A+). Absorptions commencing at 366.4 nm are observed for C7H5O2+ and assigned to the 1 2A' ← X 2A' electronic transition of (2-hydroxyphenyl)methanone ion (J+). Neutralization of J+ leads to the appearance of four absorption systems attributed to the 4 2A″, 3 2A″, 2 2A″, and 1 2A″ ← X 2A″ transitions of J with origin bands 291.3, 361.2, 393.8, and 461.2 nm.
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Affiliation(s)
- Jan Fulara
- Department of Chemistry, University of Basel , Klingelbergstrasse 80, CH-4056, Basel, Switzerland.,Institute of Physics, Polish Academy of Sciences , Al. Lotników, 32/46, PL-02-668 Warsaw, Poland
| | - Sonia Erattupuzha
- Department of Chemistry, University of Basel , Klingelbergstrasse 80, CH-4056, Basel, Switzerland
| | - Iryna Garkusha
- Department of Chemistry, University of Basel , Klingelbergstrasse 80, CH-4056, Basel, Switzerland
| | - John P Maier
- Department of Chemistry, University of Basel , Klingelbergstrasse 80, CH-4056, Basel, Switzerland
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33
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You HS, Han S, Yoon JH, Lim JS, Lee J, Kim SY, Ahn DS, Lim JS, Kim SK. Structure and dynamic role of conical intersections in the πσ*-mediated photodissociation reactions. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1072364] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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34
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Wang LS. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions. J Chem Phys 2015; 143:040901. [DOI: 10.1063/1.4927086] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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35
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Weichman ML, Kim JB, Neumark DM. Slow Photoelectron Velocity-Map Imaging Spectroscopy of the ortho-Hydroxyphenoxide Anion. J Phys Chem A 2015; 119:6140-7. [PMID: 25744814 DOI: 10.1021/acs.jpca.5b00768] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report high-resolution photodetachment spectra of cryogenically cooled ortho-hydroxyphenoxide anions (o-HOC6H4O(-)) using slow photoelectron velocity-map imaging spectroscopy (cryo-SEVI). We observe transitions to the three lowest-lying electronic states of the ortho-hydroxyphenoxy radical, and resolve detailed vibrational features. Comparison to Franck-Condon simulations allows for clear assignment of vibronic structure. We find an electron affinity of 2.3292(4) eV for the neutral X̃(2)A″ ground state, improving upon the accuracy of previous experiments. We measure term energies of 1.4574(7) eV and 1.5922(48) eV for the Ã(2)A' and B̃(2)A″ excited states respectively, representing their first resolution and clear assignment. Photodetachment threshold effects are considered to explain the structure of these bands.
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Affiliation(s)
- Marissa L Weichman
- †Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jongjin B Kim
- †Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Daniel M Neumark
- †Department of Chemistry, University of California, Berkeley, California 94720, United States.,‡Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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36
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Wenge AM, Karsili TNV, Rodríguez JD, Cotterell MI, Marchetti B, Dixon RN, Ashfold MNR. Tuning photochemistry: substituent effects on πσ* state mediated bond fission in thioanisoles. Phys Chem Chem Phys 2015; 17:16246-56. [DOI: 10.1039/c5cp01660f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic branching in the thiophenoxyl radicals formed by UV photolysis of thioanisole can be tuned by placing electron withdrawing/donating substituents at the 4-position.
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Affiliation(s)
- Andreas M. Wenge
- School of Chemistry
- University of Bristol
- Cantock's Close
- Bristol BS8 1TS
- UK
| | | | | | | | - Barbara Marchetti
- School of Chemistry
- University of Bristol
- Cantock's Close
- Bristol BS8 1TS
- UK
| | - Richard N. Dixon
- School of Chemistry
- University of Bristol
- Cantock's Close
- Bristol BS8 1TS
- UK
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37
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Buytendyk AM, Graham JD, Collins KD, Bowen KH, Wu CH, Wu JI. The hydrogen bond strength of the phenol–phenolate anionic complex: a computational and photoelectron spectroscopic study. Phys Chem Chem Phys 2015; 17:25109-13. [DOI: 10.1039/c5cp04754d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The phenol–phenolate anionic complex was studied in vacuo by negative ion photoelectron spectroscopy using 193 nm photons and by density functional theory (DFT) computations at the ωB97XD/6-311+G(2d,p) level.
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Affiliation(s)
| | | | - Kim D. Collins
- IMET and Department of Microbiology and Immunology
- University of Maryland School of Medicine
- Baltimore
- USA
| | - Kit H. Bowen
- Department of Chemistry
- Johns Hopkins University
- Baltimore
- USA
| | - Chia-Hua Wu
- Department of Chemistry
- University of Houston
- Houston
- USA
| | - Judy I. Wu
- Department of Chemistry
- University of Houston
- Houston
- USA
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38
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Tentscher PR, Seidel R, Winter B, Guerard JJ, Arey JS. Exploring the aqueous vertical ionization of organic molecules by molecular simulation and liquid microjet photoelectron spectroscopy. J Phys Chem B 2014; 119:238-56. [PMID: 25516011 DOI: 10.1021/jp508053m] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To study the influence of aqueous solvent on the electronic energy levels of dissolved organic molecules, we conducted liquid microjet photoelectron spectroscopy (PES) measurements of the aqueous vertical ionization energies (VIEaq) of aniline (7.49 eV), veratrole alcohol (7.68 eV), and imidazole (8.51 eV). We also reanalyzed previously reported experimental PES data for phenol, phenolate, thymidine, and protonated imidazolium cation. We then simulated PE spectra by means of QM/MM molecular dynamics and EOM-IP-CCSD calculations with effective fragment potentials, used to describe the aqueous vertical ionization energies for six molecules, including aniline, phenol, veratrole alcohol, imidazole, methoxybenzene, and dimethylsulfide. Experimental and computational data enable us to decompose the VIEaq into elementary processes. For neutral compounds, the shift in VIE upon solvation, ΔVIEaq, was found to range from ≈-0.5 to -0.91 eV. The ΔVIEaq was further explained in terms of the influence of deforming the gas phase solute into its solution phase conformation, the influence of solute hydrogen-bond donor and acceptor interactions with proximate solvent molecules, and the polarization of about 3000 outerlying solvent molecules. Among the neutral compounds, variability in ΔVIEaq appeared largely controlled by differences in solute-solvent hydrogen-bonding interactions. Detailed computational analysis of the flexible molecule veratrole alcohol reveals that the VIE is strongly dependent on molecular conformation in both gas and aqueous phases. Finally, aqueous reorganization energies of the oxidation half-cell ionization reaction were determined from experimental data or estimated from simulation for the six compounds aniline, phenol, phenolate, veratrole alcohol, dimethylsulfide, and methoxybenzene, revealing a surprising constancy of 2.06 to 2.35 eV.
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Affiliation(s)
- Peter R Tentscher
- Environmental Chemistry Modeling Laboratory, GR C2 544, Ecole Polytechnique Fédérale de Lausanne , Station 2, CH-1015 Lausanne, Switzerland
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39
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Steill JD, May AL, Campagna SR, Oomens J, Compton RN. Structure and stability of phenoxide and fluorophenoxide anions investigated with infrared multiple-photon dissociation and detachment spectroscopy and tandem mass spectrometry. J Phys Chem A 2014; 118:8597-605. [PMID: 24802281 DOI: 10.1021/jp503103a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The gas-phase infrared multiple-photon dissociation and detachment (IRMPD) vibrational action spectra of the unsubstituted phenoxide anion and a series of fluorine- and trifluoromethyl-substituted phenoxide anions in the spectral region between 600 and 1800 cm(-1) are presented along with density functional theory (DFT) harmonic vibrational frequency calculations to establish the characteristic vibrations of the phenoxide functionality. The fluorophenoxide anions studied include the conjugate bases of o-, m-, and p-fluorophenol (C6H4FO(-)) as well as o-, m-, and p-α,α,α-trifluorocresol (CF3C6H4O(-)). The influence of the substituent on the characteristic vibrational frequencies is interpreted in terms of inductive and resonance shifts. In addition to the dissociation induced by infrared multiple-photon excitation, the electron detachment is also shown to play an important role in the decomposition of the unsubstituted phenoxide. It is demonstrated that the amount of electron detachment relative to dissociation is strongly mitigated by fluorination, and interpretations aided by DFT energy calculations suggest this is primarily due to the increased availability of low-energy dissociation pathways in the substituted phenoxides. Collision-induced dissociation (CID) mass spectrometry of the parent ions is used to estimate relative energies of the dissociation processes, and particular fragmentation motifs are elucidated. In particular, overall HF and CO losses provide facile decomposition pathways, yielding interesting fragment ions such as C6H(-) or C3H2FO(-) from the CF3C6H4O(-) parent anions.
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Affiliation(s)
- Jeffrey D Steill
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
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40
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León I, Yang Z, Liu HT, Wang LS. The design and construction of a high-resolution velocity-map imaging apparatus for photoelectron spectroscopy studies of size-selected clusters. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:083106. [PMID: 25173245 DOI: 10.1063/1.4891701] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A new velocity-map imaging apparatus equipped with a laser-vaporization supersonic cluster source and a time-of-flight mass spectrometer is described for high-resolution photoelectron spectroscopy studies of size-selected cluster anions. Vibrationally cold anion clusters are produced using a laser-vaporization supersonic cluster source, size-selected by a time-of-flight mass spectrometer, and then focused co-linearly into the interaction zone of the high-resolution velocity-map imaging (VMI) system. The multilens VMI system is optimized via systematic simulations and can reach a resolution of 1.2 cm(-1) (FWHM) for near threshold electrons while maintaining photoelectron kinetic energy resolutions (ΔKE/KE) of ~0.53% for higher energy electrons. The new VMI lens has superior focusing power over a large energy range, yielding highly circular images with distortions no larger than 1.0025 between the long and short radii. The detailed design, simulation, construction, testing, and performance of the high-resolution VMI apparatus are presented.
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Affiliation(s)
- Iker León
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Zheng Yang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Hong-Tao Liu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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41
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Han S, Lim JS, Yoon JH, Lee J, Kim SY, Kim SK. Conical intersection seam and bound resonances embedded in continuum observed in the photodissociation of thioanisole-d3. J Chem Phys 2014; 140:054307. [DOI: 10.1063/1.4863449] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Harrison AW, Lim JS, Ryazanov M, Wang G, Gao S, Neumark DM. Photodissociation dynamics of the thiophenoxy radical at 248, 193, and 157 nm. J Phys Chem A 2013; 117:11970-8. [PMID: 23822615 DOI: 10.1021/jp403229h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The photodissociation dynamics of the thiophenoxy radical (C6H5S) have been investigated using fast beam coincidence translational spectroscopy. Thiophenoxy radicals were produced by photodetachment of the thiophenoxide anion followed by photodissociation at 248 nm (5.0 eV), 193 nm (6.4 eV), and 157 nm (7.9 eV). Experimental results indicate two major competing dissociation channels leading to SH + C6H4 (o-benzyne) and CS + C5H5 (cyclopentadienyl) with a minor contribution of S + C6H5 (phenyl). Photofragment mass distributions and translational energy distributions were measured at each dissociation wavelength. Transition states and minima for each reaction pathway were calculated using density functional theory to facilitate experimental interpretation. The proposed dissociation mechanism involves internal conversion from the initially prepared electronic excited state to the ground electronic state followed by statistical dissociation. Calculations show that SH loss involves a single isomerization step followed by simple bond fission. For both SH and S loss, C-S bond cleavage proceeds without an exit barrier. By contrast, the CS loss pathway entails multiple transition states and minima as it undergoes five membered ring formation and presents a small barrier with respect to products. The calculated reaction pathway is consistent with the experimental translational energy distributions in which the CS loss channel has a broader distribution peaking farther away from zero than the corresponding distributions for SH loss.
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Affiliation(s)
- Aaron W Harrison
- Department of Chemistry, University of California , Berkeley, California 94720, United States
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Kim JB, Weichman ML, Yacovitch TI, Shih C, Neumark DM. Slow photoelectron velocity-map imaging spectroscopy of the C9H7 (indenyl) and C13H9 (fluorenyl) anions. J Chem Phys 2013; 139:104301. [DOI: 10.1063/1.4820138] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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44
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Liu HT, Ning CG, Huang DL, Dau PD, Wang LS. Observation of Mode-Specific Vibrational Autodetachment from Dipole-Bound States of Cold Anions. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304695] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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45
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Observation of Mode-Specific Vibrational Autodetachment from Dipole-Bound States of Cold Anions. Angew Chem Int Ed Engl 2013; 52:8976-9. [DOI: 10.1002/anie.201304695] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Indexed: 11/07/2022]
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46
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Harris SJ, Murdock D, Zhang Y, Oliver TAA, Grubb MP, Orr-Ewing AJ, Greetham GM, Clark IP, Towrie M, Bradforth SE, Ashfold MNR. Comparing molecular photofragmentation dynamics in the gas and liquid phases. Phys Chem Chem Phys 2013; 15:6567-82. [PMID: 23552482 DOI: 10.1039/c3cp50756d] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article explores the extent to which insights gleaned from detailed studies of molecular photodissociations in the gas phase (i.e. under isolated molecule conditions) can inform our understanding of the corresponding photofragmentation processes in solution. Systems selected for comparison include a thiophenol (p-methylthiophenol), a thioanisole (p-methylthioanisole) and phenol, in vacuum and in cyclohexane solution. UV excitation in the gas phase results in RX-Y (X = O, S; Y = H, CH3) bond fission in all cases, but over timescales that vary by ~4 orders of magnitude - all of which behaviours can be rationalised on the basis of the relevant bound and dissociative excited state potential energy surfaces (PESs) accessed by UV photoexcitation, and of the conical intersections that facilitate radiationless transfer between these PESs. Time-resolved UV pump-broadband UV/visible probe and/or UV pump-broadband IR probe studies of the corresponding systems in cyclohexane solution reveal additional processes that are unique to the condensed phase. Thus, for example, the data clearly reveal evidence of (i) vibrational relaxation of the photoexcited molecules prior to their dissociation and of the radical fragments formed upon X-Y bond fission, and (ii) geminate recombination of the RX and Y products (leading to reformation of the ground state parent and/or isomeric adducts). Nonetheless, the data also show that, in each case, the characteristics (and the timescale) of the initial bond fission process that occurs under isolated molecule conditions are barely changed by the presence of a weakly interacting solvent like cyclohexane. These condensed phase studies are then extended to an ether analogue of phenol (allyl phenyl ether), wherein UV photo-induced RO-allyl bond fission constitutes the first step of a photo-Claisen rearrangement.
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Affiliation(s)
- Stephanie J Harris
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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Yoon JH, Lim JS, Woo KC, Kim MS, Kim SK. Chemical Substitution Effect on Energetic and Structural Differences between Ground and First Electronically Excited States of Thiophenoxyl Radicals. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.2.415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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48
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Roberts GM, Hadden DJ, Bergendahl LT, Wenge AM, Harris SJ, Karsili TNV, Ashfold MNR, Paterson MJ, Stavros VG. Exploring quantum phenomena and vibrational control in σ* mediated photochemistry. Chem Sci 2013. [DOI: 10.1039/c2sc21865h] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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49
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Hock C, Kim JB, Weichman ML, Yacovitch TI, Neumark DM. Slow photoelectron velocity-map imaging spectroscopy of cold negative ions. J Chem Phys 2012; 137:244201. [DOI: 10.1063/1.4772406] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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50
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Oliver TAA, King GA, Tew DP, Dixon RN, Ashfold MNR. Controlling Electronic Product Branching at Conical Intersections in the UV Photolysis of para-Substituted Thiophenols. J Phys Chem A 2012; 116:12444-59. [DOI: 10.1021/jp308804d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Graeme A. King
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - David P. Tew
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Richard N. Dixon
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
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