1
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Robinson D, Alarfaji SS, Hirst JD. Benzene, Toluene, and Monosubstituted Derivatives: Diabatic Nature of the Oscillator Strengths of S 1 ← S 0 Transitions. J Phys Chem A 2021; 125:5237-5245. [PMID: 34132093 PMCID: PMC8279645 DOI: 10.1021/acs.jpca.1c01685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/05/2021] [Indexed: 11/28/2022]
Abstract
For benzene, toluene, aniline, fluorobenzene, and phenol, even sophisticated treatments of electron correlation, such as MRCI and XMS-CASPT2 calculations, show oscillator strengths typically lower than experiment. Inclusion of a simple pseudo-diabatization approach to perturb the S1 state with approximate vibronic coupling to the S2 state for each molecule results in more accurate oscillator strengths. Their absolute values agree better with experiment for all molecules except aniline. When the coupling between the S1 and S2 states is strong at the S0 geometry, the simple diabatization scheme performs less well with respect to the oscillator strengths relative to the adiabatic values. However, we expect the scheme to be useful in many cases where the coupling is weak to moderate (where the maximum component of the coupling has a magnitude less than 1.5 au). Such calculations give an insight into the effects of vibronic coupling of excited states on UV/vis spectra.
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Affiliation(s)
- David Robinson
- Department
of Chemistry and Forensics, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United
Kingdom
| | - Saleh S. Alarfaji
- School
of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Jonathan D. Hirst
- School
of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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2
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Zhou L, Liu Y, Sun T, Yin H, Zhao Y, Lv H, Xu H. Strong Field Ionization-Photofragmentation on Ultrafast Evolution of Electronic States of Toluene Cations. J Phys Chem A 2021; 125:2095-2100. [PMID: 33662205 DOI: 10.1021/acs.jpca.0c11547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ultrafast time-resolved strong field ionization-photofragmentation (SFI-PF) has emerged as a useful method for investigation of dynamics of molecular cations. Here we perform a SFI-PF study on the electronic states of toluene cations. By measuring the ion yields as a function of delay time, we obtain the transients of both parent and daughter ions, which show ultrafast decays and out-of-phase oscillations. The results provide the first experimental evidence of D1-D0 ultrafast relaxation of toluene cations occurring in about 530 fs and indicate coincident resonance between the vibrational states in D1 and D0 leading to oscillations with a period of about 2.05 ps. Our study should shed some light on the ultrafast photochemistry involving complex molecular cations.
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Affiliation(s)
- Longxing Zhou
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Yang Liu
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Tian Sun
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Hang Yin
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Yiwen Zhao
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Hang Lv
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Haifeng Xu
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
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3
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Zachariou A, Hawkins AP, Collier P, Howe RF, Lennon D, Parker SF. The Methyl Torsion in Unsaturated Compounds. ACS OMEGA 2020; 5:2755-2765. [PMID: 32095699 PMCID: PMC7033956 DOI: 10.1021/acsomega.9b03351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/24/2020] [Indexed: 05/11/2023]
Abstract
How the methyl torsion transition energy in unsaturated systems is affected by its environment is investigated. It is strongly influenced by both its immediate neighborhood, (the number of methyl groups present in the molecule) and the intermolecular interactions. It is clear that the intermolecular interactions have a major influence on the torsion transition energy, as demonstrated unambiguously previously for mesitylene and also seen here for other systems. In part, this may be caused by the fact that the methyl torsion is rarely a pure mode (unless enforced by symmetry). Where the crystal structure is available, the assignments have been supported by CASTEP calculations of the unit cell. The agreement between the observed and calculated spectra is generally good, although not perfect, toluene being a case in point, and highlights just how demanding it is to obtain accurate transition energies for low energy modes. The disagreement between observed and calculated inelastic neutron scattering spectra for meta-xylene and 9,10 dimethylanthracene is so severe that it would suggest that there are additional phases to those presently known. Comparison between the full periodic calculations and those for the isolated molecule shows that intermolecular interactions raise the methyl torsion transition energy by at least 8% and in some cases by more than 50%. The presence of more than one methyl group in the molecule generally raises the average torsion energy from the <100 cm-1 seen for single methyl groups to 150-200 cm-1.
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Affiliation(s)
- Andrea Zachariou
- School
of Chemistry, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, U.K.
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory,
Chilton, Oxon OX11 0FA, U.K.
| | - Alexander P. Hawkins
- School
of Chemistry, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, U.K.
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory,
Chilton, Oxon OX11 0FA, U.K.
| | - Paul Collier
- Johnson
Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.
| | - Russell F. Howe
- Department
of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - David Lennon
- School
of Chemistry, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, U.K.
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory,
Chilton, Oxon OX11 0FA, U.K.
| | - Stewart F. Parker
- School
of Chemistry, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, U.K.
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory,
Chilton, Oxon OX11 0FA, U.K.
- ISIS
Neutron and Muon Source, STFC Rutherford
Appleton Laboratory, Chilton, Oxon OX11 0QX, U.K.
- E-mail: . Phone: +44 (0)1235 446182
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4
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Woo KC, Kim SK. Real-Time Observation of Fermi Resonances in the S 1 State of Phenol. J Phys Chem Lett 2020; 11:161-165. [PMID: 31830787 DOI: 10.1021/acs.jpclett.9b03393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fermi resonances in the first electronically excited (S1) state of phenol have been observed in real time. Quantum beats associated with coherent superposition of Fermi resonant eigenstates are manifested as temporal oscillations of the ionization cross sections of which the amplitudes are strongly dependent on the total ionization energy. This indicates that coherently excited eigenstates are effectively decomposed into their zeroth-order states, providing the unique opportunity for the investigation of nonstationary state dynamics in real-time. Energy gaps (Δν̃) of eigenstates within the laser coherence width have been most precisely determined up to date, giving Δν̃ ∼ 3.302 ± 0.001 or 1.655 ± 0.001 cm-1 for the 11/4110b1 or 122/8a1 Fermi doublets, respectively. Dephasing rate suddenly increases as the S1 internal energy becomes above ∼1500 cm-1, revealing the important role of energy randomization dynamics during the H atom tunneling process of phenol in S1.
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Affiliation(s)
- Kyung Chul Woo
- 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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5
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Gardner AM, Whalley LE, Kemp DJ, Tuttle WD, Wright TG. Identification of separate isoenergetic routes for vibrational energy flow in p-fluorotoluene. J Chem Phys 2019; 151:154302. [DOI: 10.1063/1.5126179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Adrian M. Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Laura E. Whalley
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - David J. Kemp
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D. Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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6
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Kemp DJ, Fryer EF, Davies AR, Wright TG. Vibration-modified torsional potentials and vibration-torsion (“vibtor”) levels in them-fluorotoluene cation. J Chem Phys 2019; 151:084311. [DOI: 10.1063/1.5116520] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David J. Kemp
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Elizabeth F. Fryer
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Alexander R. Davies
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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7
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Kemp DJ, Tuttle WD, Gardner AM, Whalley LE, Wright TG. Observation of the onset of torsion-induced, mode-specific dissipative intramolecular vibrational redistribution (IVR). J Chem Phys 2019. [DOI: 10.1063/1.5115329] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David J. Kemp
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D. Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Adrian M. Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Laura E. Whalley
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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8
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Tew DP, Hättig C, Graf NK. Anharmonic excited state frequencies of para-difluorobenzene, toluene and catechol using analytic RI-CC2 second derivatives. Phys Chem Chem Phys 2019; 21:14063-14072. [PMID: 30656295 DOI: 10.1039/c8cp06952b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Analytic second nuclear derivatives for excited electronic state energies have been implemented for the resolution-of-the-identity accelerated CC2, CIS(D∞) and ADC(2) models. Our efficient implementation with O(N2) memory demands enables the treatment of medium sized molecules with large basis sets and high numerical precision and thereby paves the way for semi-numerical evaluation of the higher-order derivatives required for anharmonic corrections to excited state vibrational frequencies. We compare CC2 harmonic and anharmonic excited state frequencies with experimental values for para-difluorobenzene, toluene and catechol. Basis set problems occur for out-of-plane bending vibrations due to intramolecular basis set superposition error. For non-planar molecules and in plane modes of planar molecules, the agreement between theory and experiment is better than 30 cm-1 on average and we reassign a number of experimental bands on the basis of the ab initio predictions.
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Affiliation(s)
- David P Tew
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany.
| | - Christof Hättig
- Quantum Chemistry Group, Ruhr-Universität Bochum, 44780 Bochum, Germany.
| | - Nora K Graf
- Quantum Chemistry Group, Ruhr-Universität Bochum, 44780 Bochum, Germany.
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9
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Stewart LD, Gascooke JR, Lawrance WD. A strong interaction between torsion and vibration in S0 and S1 m-fluorotoluene. J Chem Phys 2019; 150:174303. [DOI: 10.1063/1.5094454] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Laurence D. Stewart
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide SA 5001, Australia
| | - Jason R. Gascooke
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide SA 5001, Australia
| | - Warren D. Lawrance
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide SA 5001, Australia
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10
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Kemp DJ, Whalley LE, Gardner AM, Tuttle WD, Warner LG, Wright TG. Complexity surrounding an apparently simple Fermi resonance in p-fluorotoluene revealed using two-dimensional laser-induced fluorescence (2D-LIF) spectroscopy. J Chem Phys 2019; 150:064306. [DOI: 10.1063/1.5083682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David J. Kemp
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Laura E. Whalley
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Adrian M. Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D. Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Lewis G. Warner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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11
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Kemp DJ, Gardner AM, Tuttle WD, Wright TG. Unravelling overlaps and torsion-facilitated coupling using two-dimensional laser-induced fluorescence. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1554865] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- David J. Kemp
- School of Chemistry, University of Nottingham, Nottingham, UK
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12
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Gascooke JR, Stewart LD, Sibley PG, Lawrance WD. Pervasive interactions between methyl torsion and low frequency vibrations in S0 and S1 p-fluorotoluene. J Chem Phys 2018; 149:074301. [DOI: 10.1063/1.5035461] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jason R. Gascooke
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001, Australia
| | - Laurence D. Stewart
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001, Australia
| | - Paul G. Sibley
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001, Australia
| | - Warren D. Lawrance
- College of Science and Engineering, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001, Australia
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13
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Gardner AM, Tuttle WD, Whalley LE, Wright TG. Direct observation of vibrational energy dispersal via methyl torsions. Chem Sci 2018; 9:2270-2283. [PMID: 29719700 PMCID: PMC5897844 DOI: 10.1039/c7sc05309f] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 01/24/2018] [Indexed: 01/01/2023] Open
Abstract
Explicit evidence for the role of methyl rotor levels in promoting energy dispersal is reported. A set of coupled zero-order vibration/vibration-torsion (vibtor) levels in the S1 state of para-fluorotoluene (pFT) are investigated. Two-dimensional laser-induced fluorescence (2D-LIF) and two-dimensional zero-kinetic-energy (2D-ZEKE) spectra are reported, and the assignment of the main features in both sets of spectra reveals that the methyl torsion is instrumental in providing a route for coupling between vibrational levels of different symmetry classes. We find that there is very localized, and selective, dissipation of energy via doorway states, and that, in addition to an increase in the density of states, a critical role of the methyl group is a relaxation of symmetry constraints compared to direct vibrational coupling.
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Affiliation(s)
- Adrian M Gardner
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - William D Tuttle
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - Laura E Whalley
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - Timothy G Wright
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
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14
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Kemp DJ, Whalley LE, Tuttle WD, Gardner AM, Speake BT, Wright TG. Vibrations of the p-chlorofluorobenzene cation. Phys Chem Chem Phys 2018; 20:12503-12516. [DOI: 10.1039/c8cp01274a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibrational wavenumbers are established for twenty modes of the p-chlorofluorbenzene cation and two Fermi resonances are identified in the S1 state.
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Affiliation(s)
- David J. Kemp
- School of Chemistry
- University of Nottingham
- Nottingham
- UK
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15
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16
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Kim SY, Lee J, Kim SK. Conformer specific nonadiabatic reaction dynamics in the photodissociation of partially deuterated thioanisoles (C 6H 5S-CH 2D and C 6H 5S-CHD 2). Phys Chem Chem Phys 2017; 19:18902-18912. [PMID: 28707684 DOI: 10.1039/c7cp03036c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we have investigated nonadiabatic dynamics in the vicinity of conical intersections for predissociation reactions of partially deuterated thioanisole molecules: C6H5S-CH2D and C6H5S-CHD2. Each isotopomer has two distinct rotational conformers according to the geometrical position of D or H of the methyl moiety with respect to the molecular plane for C6H5S-CH2D or C6H5S-CHD2, respectively, as spectroscopically characterized in our earlier report [J. Lee, S.-Y. Kim and S. K. Kim, J. Phys. Chem. A, 2014, 118, 1850]. Since identification and separation of two different rotational conformers of each isotopomer have been unambiguously done, we could interrogate nonadiabatic dynamics of thioanisole in terms of both H/D substitutional and conformational structural effects. Nonadiabatic transition probability, estimated by the experimentally measured branching ratio of the nonadiabatically produced ground-state channel giving C6H5S·(X[combining tilde]) versus the adiabatic excited-state channel leading to the C6H5S·(Ã) radical, shows resonance-like increases at symmetric (νs) or asymmetric (7a) S-CH2D (or S-CHD2) stretching mode excitation in S1 for all conformational isomers of two isotopomers. However, absolute probabilistic value of the nonadiabatic transition is found to vary quite drastically depending on different conformers and isotopomers. The experimental finding that nonadiabatic transition dynamics are very sensitive to subtle changes in the nuclear configuration within the Franck-Condon region induced by the H/D substitution indicates that the S1/S2 conical intersection seam is quite narrowly defined in the multi-dimensional nuclear configurational space as far as the S-methyl predissociation reaction is concerned. In order to understand the relation between molecular structure and nonadiabaticity of reaction, potential energy surfaces near S1/S2 conical intersections have been theoretically calculated along νs and 7a normal mode coordinates for all conformational isomers. Slow-electron velocity map imaging (SEVI) spectroscopy is employed to unravel the extent of intramolecular vibrational redistribution (IVR) for particular mode excitations of S1, providing insights into the dynamic interplay between IVR and nonadiabatic transition probability near the conical intersection seam.
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Affiliation(s)
- So-Yeon Kim
- Department of Chemistry, KAIST, Daejeon 305-701, Republic of Korea.
| | - Jeongmook Lee
- Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daejeon 305-353, Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 305-701, Republic of Korea.
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17
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Tuttle WD, Gardner AM, Whalley LE, Wright TG. Vibration and vibration-torsion levels of the S 1 state of para-fluorotoluene in the 580-830 cm -1 range: Interactions and coincidences. J Chem Phys 2017; 146:244310. [PMID: 28668017 DOI: 10.1063/1.4986862] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A study of the vibration and vibration-torsion levels of para-fluorotoluene in the 580-830 cm-1 region is presented, where a number of features are located whose identity is complicated by interactions and overlap. We examine this region with a view to ascertaining the assignments of the bands; in particular, identifying those that arise from interactions involving various zero-order states (ZOSs) involving both vibrations and torsions. Resonance-enhanced multiphoton ionization (REMPI) is employed to identify the wavenumbers of the relevant transitions, and subsequently zero-kinetic-energy (ZEKE) spectra are recorded to assign the various eigenstates. In some cases, a set of ZEKE spectra are recorded across the wavenumber range of a REMPI feature, and we construct what we term a two-dimensional ZEKE (2D-ZEKE) spectrum, which allows the changing ZOS contributions to the eigenstates to be ascertained. Assignment of the observed bands is aided by quantum chemical calculations and all b1 and a2 symmetry vibrational wavenumbers are now determined in the S1 state and cation, as well as those of the D10 vibration. We also compare to the activity seen in the corresponding S1 ← S0 spectrum of para-difluorobenzene.
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Affiliation(s)
- William D Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Adrian M Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Laura E Whalley
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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18
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Li Z, Hirst JD. Quantitative first principles calculations of protein circular dichroism in the near-ultraviolet. Chem Sci 2017; 8:4318-4333. [PMID: 29163925 PMCID: PMC5637123 DOI: 10.1039/c7sc00586e] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/23/2017] [Indexed: 11/30/2022] Open
Abstract
Vibrational structure in the near-UV circular dichroism (CD) spectra of proteins is an important source of information on protein conformation and can be exploited to study structure and folding. A fully quantitative theory of the relationship between protein conformation and optical spectroscopy would facilitate deeper interpretation of and insight into biophysical and simulation studies of protein dynamics and folding. We have developed new models of the aromatic side chain chromophores toluene, p-cresol and 3-methylindole, which incorporate ab initio calculations of the Franck-Condon effect into first principles calculations of CD using an exciton approach. The near-UV CD spectra of 40 proteins are calculated with the new parameter set and the correlation between the computed and the experimental intensity from 270 to 290 nm is much improved. The contribution of individual chromophores to the CD spectra has been calculated for several mutants and in many cases helps rationalize changes in their experimental spectra. Considering conformational flexibility by using families of NMR structures leads to further improvements for some proteins and illustrates an informative level of sensitivity to side chain conformation. In several cases, the near-UV CD calculations can distinguish the native protein structure from a set of computer-generated misfolded decoy structures.
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Affiliation(s)
- Zhuo Li
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - Jonathan D Hirst
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
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19
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Tuttle WD, Gardner AM, O'Regan KB, Malewicz W, Wright TG. Vibrational and vibrational-torsional interactions in the 0-600 cm -1 region of the S 1← S 0 spectrum of p-xylene investigated with resonance-enhanced multiphoton ionization (REMPI) and zero-kinetic-energy (ZEKE) spectroscopy. J Chem Phys 2017; 146:124309. [PMID: 28388145 DOI: 10.1063/1.4977897] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We assign the 0-600 cm-1 region of the S1← S0 transition in p-xylene (p-dimethylbenzene) using resonance-enhanced multiphoton ionization (REMPI) and zero-kinetic-energy (ZEKE) spectroscopy. In the 0-350 cm-1 range as well as the intense origin band, there are a number of torsional and vibration-torsion (vibtor) features. The latter are discussed in more detail in Paper I [A. M. Gardner et al., J. Chem. Phys. 146, 124308 (2017)]. Here we focus on the origin and the 300-600 cm-1 region, where vibrational bands and some vibtor activity are observed. From the origin ZEKE spectrum, we derive the ionization energy of p-xylene as 68200 ± 5 cm-1. The assignment of the REMPI spectrum is based on the activity observed in the ZEKE spectra coupled with knowledge of the vibrational wavenumbers obtained from quantum chemical calculations. We assign several isolated vibrations and a complex Fermi resonance that is found to comprise contributions from both vibrations and vibtor levels, and we examine this via a two-dimensional ZEKE spectrum. A number of the vibrational features in the REMPI and ZEKE spectra of p-xylene that have been reported previously are reassigned and now largely consist of totally symmetric contributions. We briefly discuss the appearance of non-Franck-Condon allowed transitions. Finally, we find remarkably similar spectral activity to that in the related disubstituted benzenes, para-difluorobenzene, and para-fluorotoluene.
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Affiliation(s)
- William D Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Adrian M Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Kieran B O'Regan
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William Malewicz
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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Gardner AM, Tuttle WD, Groner P, Wright TG. Molecular symmetry group analysis of the low-wavenumber torsions and vibration-torsions in the S 1 state and ground state cation of p-xylene: An investigation using resonance-enhanced multiphoton ionization (REMPI) and zero-kinetic-energy (ZEKE) spectroscopy. J Chem Phys 2017; 146:124308. [PMID: 28388144 DOI: 10.1063/1.4977896] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
For the first time, a molecular symmetry group (MSG) analysis has been undertaken in the investigation of the electronic spectroscopy of p-xylene (p-dimethylbenzene). Torsional and vibration-torsional (vibtor) levels in the S1 state and ground state of the cation of p-xylene are investigated using resonance-enhanced multiphoton ionization (REMPI) and zero-kinetic-energy (ZEKE) spectroscopy. In the present work, we concentrate on the 0-350 cm-1 region, where there are a number of torsional and vibtor bands and we discuss the assignment of this region. In Paper II [W. D. Tuttle et al., J. Chem. Phys. 146, 124309 (2017)], we examine the 350-600 cm-1 region where vibtor levels are observed as part of a Fermi resonance. The similarity of much of the observed spectral activity to that in the related substituted benzenes, toluene and para-fluorotoluene, is striking, despite the different symmetries. The discussion necessitates a consideration of the MSG of p-xylene, which has been designated G72, but we shall also designate [{3,3}]D2h and we include the symmetry operations, character table, and direct product table for this. We also discuss the symmetries of the internal rotor (torsional) levels and the selection rules for the particular electronic transition of p-xylene investigated here.
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Affiliation(s)
- Adrian M Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Peter Groner
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA
| | - Timothy G Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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Gardner AM, Tuttle WD, Whalley L, Claydon A, Carter JH, Wright TG. Torsion and vibration-torsion levels of the S 1 and ground cation electronic states of para-fluorotoluene. J Chem Phys 2016; 145:124307. [PMID: 27782641 DOI: 10.1063/1.4962822] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the low-energy transitions (0-570 cm-1) of the S1 state of para-fluorotoluene (pFT) using a combination of resonance-enhanced multiphoton ionization and zero-kinetic-energy (ZEKE) spectroscopy and quantum chemical calculations. By using various S1 states as intermediate levels, we obtain ZEKE spectra. The differing activity observed allows detailed assignments to be made of both the cation and S1 low-energy levels. The assignments are in line with the recently published work on toluene from the Lawrance group [J. R. Gascooke et al., J. Chem. Phys. 143, 044313 (2015)], which considered vibration-torsion coupling in depth for the S1 state of toluene. In addition, we investigate whether two bands that occur in the range 390-420 cm-1 are the result of a Fermi resonance; we present evidence for weak coupling between various vibrations and torsions that contribute to this region. This work has led to the identification of a number of misassignments in the literature, and these are corrected.
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Affiliation(s)
- Adrian M Gardner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Laura Whalley
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Andrew Claydon
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Joseph H Carter
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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22
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Andrejeva A, Tuttle WD, Harris JP, Wright TG. Resonance-enhanced multiphoton ionization (REMPI) spectroscopy of bromobenzene and its perdeuterated isotopologue: Assignment of the vibrations of the S0, S1, and D0+ states of bromobenzene and the S0 and D0+ states of iodobenzene. J Chem Phys 2015; 143:244320. [DOI: 10.1063/1.4938501] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anna Andrejeva
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D. Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Joe P. Harris
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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23
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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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Andrejeva A, Tuttle WD, Harris JP, Wright TG. Assignment of the vibrations of the S0, S1, and D0+ states of perhydrogenated and perdeuterated isotopologues of chlorobenzene. J Chem Phys 2015; 143:104312. [DOI: 10.1063/1.4929996] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anna Andrejeva
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D. Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Joe P. Harris
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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25
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Serralheiro C, Duflot D, da Silva FF, Hoffmann SV, Jones NC, Mason NJ, Mendes B, Limão-Vieira P. Toluene Valence and Rydberg Excitations as Studied by ab initio Calculations and Vacuum Ultraviolet (VUV) Synchrotron Radiation. J Phys Chem A 2015; 119:9059-69. [PMID: 26244250 DOI: 10.1021/acs.jpca.5b05080] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electronic spectroscopy of isolated toluene in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 4.0-10.8 eV energy range, with absolute cross-section measurements derived. We present the first set of ab initio calculations (vertical energies and oscillator strengths), which we use in the assignment of valence and Rydberg transitions of the toluene molecule. The spectrum reveals several new features not previously reported in the literature, with particular relevance to 7.989 and 8.958 eV, which are here tentatively assigned to the π*(17a') ← σ(15a') and 1π*(10a″) ← 1π(14a') transitions, respectively. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of toluene in the upper stratosphere (20-50 km).
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Affiliation(s)
- C Serralheiro
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal.,Centro de Engenharia Mecânica e Sustentabilidade de Recursos (MEtRICs), Departamento de Ciências e Tecnologia da Biomassa, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal
| | - D Duflot
- Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM), UMR CNRS 8523, Université de Lille , F-59655 Villeneuve d'Ascq Cedex, France
| | - F Ferreira da Silva
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal
| | - S V Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University , Ny Munkegade 120, DK-8000, Aarhus C, Denmark
| | - N C Jones
- ISA, Department of Physics and Astronomy, Aarhus University , Ny Munkegade 120, DK-8000, Aarhus C, Denmark
| | - N J Mason
- Department of Physical Sciences, The Open University , Walton Hall, Milton Keynes, MK7 6AA, U.K
| | - B Mendes
- Centro de Engenharia Mecânica e Sustentabilidade de Recursos (MEtRICs), Departamento de Ciências e Tecnologia da Biomassa, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal
| | - P Limão-Vieira
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal.,Department of Physical Sciences, The Open University , Walton Hall, Milton Keynes, MK7 6AA, U.K
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Harris JP, Andrejeva A, Tuttle WD, Pugliesi I, Schriever C, Wright TG. Vibrations of the S1 state of fluorobenzene-h5 and fluorobenzene-d5 via resonance-enhanced multiphoton ionization (REMPI) spectroscopy. J Chem Phys 2014; 141:244315. [DOI: 10.1063/1.4904706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joe P. Harris
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Anna Andrejeva
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - William D. Tuttle
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Igor Pugliesi
- Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 München, Germany
| | - Christian Schriever
- Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 München, Germany
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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