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Substituents affect the mechanism of photochemical E-Z isomerization of diarylethene triazoles via adiabatic singlet excited state pathway or via triplet excited state. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113567] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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2
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He Z, Xue R, Lei Y, Yu L, Zhu C. Photorelaxation Pathways of 4-( N, N-Dimethylamino)-4'-nitrostilbene Upon S 1 Excitation Revealed by Conical Intersection and Intersystem Crossing Networks. Molecules 2020; 25:molecules25092230. [PMID: 32397393 PMCID: PMC7248955 DOI: 10.3390/molecules25092230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 11/16/2022] Open
Abstract
Multi-state n-electron valence state second order perturbation theory (MS-NEVPT2) was utilized to reveal the photorelaxation pathways of 4-(N,N-dimethylamino)-4′-nitrostilbene (DANS) upon S1 excitation. Within the interwoven networks of five S1/S0 and three T2/T1 conical intersections (CIs), and three S1/T2, one S1/T1 and one S0/T1 intersystem crossings (ISCs), those competing nonadiabatic decay pathways play different roles in trans-to-cis and cis-to-trans processes, respectively. After being excited to the Franck–Condon (FC) region of the S1 state, trans-S1-FC firstly encounters an ultrafast conversion to quinoid form. Subsequently, the relaxation mainly proceeds along the triplet pathway, trans-S1-FC → ISC-S1/T2-trans → CI-T2/T1-trans → ISC-S0/T1-twist → trans- or cis-S0. The singlet relaxation pathway mediated by CI-S1/S0-twist-c is hindered by the prominent energy barrier on S1 surface and by the reason that CI-S1/S0-trans and CI-S1/S0-twist-t are both not energetically accessible upon S1 excitation. On the other hand, the cis-S1-FC lies at the top of steeply decreasing potential energy surfaces (PESs) towards the CI-S1/S0-twist-c and CI-S1/S0-DHP regions; therefore, the initial twisting directions of DN and DAP moieties determine the branching ratio between αC=C twisting (cis-S1-FC → CI-S1/S0-twist-c → trans- or cis-S0) and DHP formation relaxation pathways (cis-S1-FC → CI-S1/S0-DHP → DHP-S0) on the S1 surface. Moreover, the DHP formation could also take place via the triplet relaxation pathway, cis-S1-FC → ISC-S1/T1-cis → DHP-T1 → DHP-S0, however, which may be hindered by insufficient spin-orbit coupling (SOC) strength. The other triplet pathways for cis-S1-FC mediated by ISC-S1/T2-cis are negligible due to the energy or geometry incompatibility of possible consecutive stepwise S1 → T2 → T1 or S1 → T2 → S1 processes. The present study reveals photoisomerization dynamic pathways via conical intersection and intersystem crossing networks and provides nice physical insight into experimental investigation of DANS.
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Affiliation(s)
- Ziyue He
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Shaanxi key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi’an, Shaanxi 710127, China; (Z.H.); (R.X.)
| | - Ruidi Xue
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Shaanxi key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi’an, Shaanxi 710127, China; (Z.H.); (R.X.)
| | - Yibo Lei
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Shaanxi key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi’an, Shaanxi 710127, China; (Z.H.); (R.X.)
- Correspondence: (Y.L.); (L.Y.); (C.Z.)
| | - Le Yu
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Shaanxi key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi’an, Shaanxi 710127, China; (Z.H.); (R.X.)
- Correspondence: (Y.L.); (L.Y.); (C.Z.)
| | - Chaoyuan Zhu
- Institute of Molecular Science and Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Correspondence: (Y.L.); (L.Y.); (C.Z.)
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Holzmann N, Bernasconi L, Bisby RH, Parker AW. Influence of charge transfer on the isomerisation of stilbene derivatives for application in cancer therapy. Phys Chem Chem Phys 2018; 20:27778-27790. [PMID: 30378611 DOI: 10.1039/c8cp05375h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoisomerisation of non-toxic trans-combretastatin CA4 to its cytotoxic cis isomer demonstrates the high potential of this and similar compounds for localised cancer therapy. The introduction of intramolecular charge-transfer character by altering the substituents of combretastatin systems opens up possibilities to tailor these stilbene derivatives to the special demands of anticancer drugs. In this TDDFT study we explore how absorption wavelengths for both the trans and cis isomers can be red shifted to enable deeper light penetration into tissue and how the trans → cis and cis → trans isomerisations are affected by charge transfer effects to different degrees.
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Affiliation(s)
- Nicole Holzmann
- STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK.
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Fletcher K, Krämer M, Bunz UH, Dreuw A. The π-conjugation length determines the fluorescence quenching mechanism of aromatic aldehydes in water. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Stan RC, Kros A, Akkilic N, Appel J, Sanghamitra NJM. Conductance switching and organization of two structurally related molecular wires on gold. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:953-958. [PMID: 25590414 DOI: 10.1021/la5042713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The self-assembly and electron transfer properties of adsorbed organic molecules are of interest for the construction of miniaturized molecular circuitries. We have investigated with scanning probe microscopy the self-organization of two structurally related molecular wires embedded within a supportive alkanethiol matrix. Our results evidence heterogeneous adsorption patterns of the molecular wires on gold with either incommensurate unit cells driven into assembly by lateral interactions or a dynamic, commensurate distribution on gold, along with formation of distinct 2D phases. We also observed diffusion-based conductance switching for one of the molecular wires, due to its propensity toward weaker lateral interactions and Au-S adatom formation. We have further demonstrated through the use of scanning tunneling spectroscopy differential current-voltage response for each molecular wire, despite their close structural similarity. Such molecular wires embedded in alkanethiol matrix and exhibiting conductance-switching phenomena have the potential to be used for the functionalization of electrodes in bioelectronic devices.
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Affiliation(s)
- Razvan C Stan
- Leiden Institute of Physics-Huygens Laboratories and ‡Leiden Institute of Chemistry-Gorlaeus Laboratories, Leiden University , P.O. Box 9504, 2300 RA Leiden, The Netherlands
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7
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Nance J, Jakubikova E, Kelley CT. Reaction Path Following with Sparse Interpolation. J Chem Theory Comput 2014; 10:2942-9. [PMID: 26588269 DOI: 10.1021/ct5004669] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Computing the potential energy of an N-atom molecule is an expensive optimization process of 3N - 6 molecular coordinates, so following reaction pathways as a function of all 3N - 6 coordinates is unfeasible for large molecules. In this paper, we present a method that isolates d < 3N - 6 molecular coordinates and continuously follows reaction paths on d-dimensional potential energy surfaces approximated by a Smolyak's sparse grid interpolation algorithm.1 Compared to dense grids, sparse grids efficiently improve the ratio of invested storage and computing time to approximation accuracy and thus allow one to increase the number of coordinates d in molecular reaction path following simulations. Furthermore, evaluation of the interpolant is much less expensive than the evaluation of the actual energy function, so our technique offers a computationally efficient way to simulate reaction paths on ground and excited state potential energy surfaces. To demonstrate the capabilities of our method, we present simulation results for the isomerization of 2-butene with two, three, and six degrees of freedom.
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Affiliation(s)
- James Nance
- Department of Mathematics and ‡Department of Chemsitry, North Carolina State University , Raleigh, North Carolina, United States
| | - Elena Jakubikova
- Department of Mathematics and ‡Department of Chemsitry, North Carolina State University , Raleigh, North Carolina, United States
| | - C T Kelley
- Department of Mathematics and ‡Department of Chemsitry, North Carolina State University , Raleigh, North Carolina, United States
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Lei Y, Yu L, Zhou B, Zhu C, Wen Z, Lin SH. Landscapes of four-enantiomer conical intersections for photoisomerization of stilbene: CASSCF calculation. J Phys Chem A 2014; 118:9021-31. [PMID: 24977930 DOI: 10.1021/jp5020109] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photoisomerization of cis- and trans-stilbene through conical intersections (CI) is mainly governed by four dihedral angles around central C═C double bonds. The two of them are C-C═C-C and H-C═C-H dihedral angles that are found to form a mirror rotation coordinate, and the mirror plane appears at the two dihedral angles equal to zeros with which the middle state is defined through partial optimization. There exist the first-type of hula-twist-CI enantiomers, the second-type of hula-twist-CI enantiomers, the first-type of one-bond-flip-CI enantiomers, and the second type of one-bond-flip-CI enantiomers as well as cis-enantiomers and trans-enantiomers with respect to this mirror plane. The complete active space self-consistent field method is employed to calculate minimum potential energy profile along the mirror rotation coordinate for each enantiomers, and it is found that the left-hand manifold and the right-hand manifold of potential energy surfaces can be energetically transferred via photoisomerization. Furthermore, two-dimensional potential energy surfaces in terms of the branching plane g-h coordinates are constructed at vicinity of each conical intersection, and the landscapes of conical intersections show distinct feature, and in excited-state four potential wells separated in different section of g-h plane related to different conical intersections which indicate different photoisomerization pathways.
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Affiliation(s)
- Yibo Lei
- Department of Applied Chemistry, Institute of Molecular Science and Center for Interdisciplinary Molecular Science, National Chiao-Tung University , Hsinchu 300, Taiwan
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Ioffe IN, Granovsky AA. Photoisomerization of Stilbene: The Detailed XMCQDPT2 Treatment. J Chem Theory Comput 2013; 9:4973-90. [PMID: 26583415 DOI: 10.1021/ct400647w] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the detailed XMCQDPT2/cc-pVTZ study of trans-cis photoisomerization in one of the core systems of both experimental and computational photochemistry-the stilbene molecule. For the first time, the potential energy surface (PES) of the S1 state has been directly optimized and scanned using a multistate multiconfiguration second-order perturbation theory. We characterize the trans-stilbene, pyramidalized (phantom), and DHP-cis-stilbene geometric domains of the S1 state and describe their stationary points including the transition states between them, as well as S1/S0 intersections. Also reported are the minima and the activation barriers in the ground state. Our calculations correctly predict the kinetic isotope effect due to H/D exchange at ethylenic hydrogens, the dynamic behavior of excited cis-stilbene, and trans-cis branching ratio after relaxation to S0 through a rather unsymmetric conical intersection. In general, the XMCQDPT2 results confirm the qualitative adequacy of the TDDFT (especially SF-TDDFT) picture of the excited stilbene but also reveal quantitative discrepancies that deserve further exploration.
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Affiliation(s)
- I N Ioffe
- Department of Chemistry, Lomonosov Moscow State University , Moscow, 119991, Russia
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Quantum-chemical investigation of the mechanism of trans-cis photoisomerization of 4-[2-(2-chlorophenyl)vinyl]-6,6-dimethyl-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile. Chem Heterocycl Compd (N Y) 2012. [DOI: 10.1007/s10593-012-0944-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Ultrafast cis-to-trans photoisomerization of a bridged azobenzene through nπ∗ excitation: Rotational pathway is not restricted. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2011.11.059] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Azobenzene undergoes trans→cis isomerization when irradiated with light tuned to an appropriate wavelength. The reverse cis→trans isomerization can be driven by light or occurs thermally in the dark. Azobenzene's photochromatic properties make it an ideal component of numerous molecular devices and functional materials. Despite the abundance of application-driven research, azobenzene photochemistry and the isomerization mechanism remain topics of investigation. Additional substituents on the azobenzene ring system change the spectroscopic properties and isomerization mechanism. This critical review details the studies completed to date on the 3 main classes of azobenzene derivatives. Understanding the differences in photochemistry, which originate from substitution, is imperative in exploiting azobenzene in the desired applications.
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Jiang CW, Zhou X, Xie RH, Li FL, Allen RE. Selective control of vibrational modes with sequential femtosecond-scale laser pulses. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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14
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Schwoerer H, von Eschwege KG, Bosman G, Krok P, Conradie J. Ultrafast Photochemistry of Dithizonatophenylmercury(II). Chemphyschem 2011; 12:2653-8. [DOI: 10.1002/cphc.201100337] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/29/2011] [Indexed: 11/10/2022]
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Liu L, Yuan S, Fang WH, Zhang Y. Probing Highly Efficient Photoisomerization of a Bridged Azobenzene by a Combination of CASPT2//CASSCF Calculation with Semiclassical Dynamics Simulation. J Phys Chem A 2011; 115:10027-34. [DOI: 10.1021/jp203704x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Lihong Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Shuai Yuan
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei-Hai Fang
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Yong Zhang
- Department of Chemistry, Chemical Biology, Biomedical Engineering, Stevens Institute of Technology, Castle Point on the Hudson, Hoboken, New Jersey 07030, United States
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Minezawa N, Gordon MS. Photoisomerization of stilbene: a spin-flip density functional theory approach. J Phys Chem A 2011; 115:7901-11. [PMID: 21639100 DOI: 10.1021/jp203803a] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photoisomerization process of 1,2-diphenylethylene (stilbene) is investigated using the spin-flip density functional theory (SFDFT), which has recently been shown to be a promising approach for locating conical intersection (CI) points (Minezawa, N.; Gordon, M. S. J. Phys. Chem. A2009, 113, 12749). The SFDFT method gives valuable insight into twisted stilbene to which the linear response time-dependent DFT approach cannot be applied. In contrast to the previous SFDFT study of ethylene, a distinct twisted minimum is found for stilbene. The optimized structure has a sizable pyramidalization angle and strong ionic character, indicating that a purely twisted geometry is not a true minimum. In addition, the SFDFT approach can successfully locate two CI points: the twisted-pyramidalized CI that is similar to the ethylene counterpart and another CI that possibly lies on the cyclization pathway of cis-stilbene. The mechanisms of the cis--trans isomerization reaction are discussed on the basis of the two-dimensional potential energy surface along the twisting and pyramidalization angles.
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Affiliation(s)
- Noriyuki Minezawa
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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Jiang CW, Xie RH, Li FL, Allen RE. Comparative Studies of the trans−cis Photoisomerizations of Azobenzene and a Bridged Azobenzene. J Phys Chem A 2010; 115:244-9. [DOI: 10.1021/jp107991a] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chen-Wei Jiang
- Ministry of Education (MOE) Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, and Department of Applied Physics, Xi’an Jiaotong University, Xi’an 710049, China, Department of Physics, Texas A&M University, College Station, Texas 77843, United States, and Department of Physics, Hubei University, Wuhan 430062, China
| | - Rui-Hua Xie
- Ministry of Education (MOE) Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, and Department of Applied Physics, Xi’an Jiaotong University, Xi’an 710049, China, Department of Physics, Texas A&M University, College Station, Texas 77843, United States, and Department of Physics, Hubei University, Wuhan 430062, China
| | - Fu-Li Li
- Ministry of Education (MOE) Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, and Department of Applied Physics, Xi’an Jiaotong University, Xi’an 710049, China, Department of Physics, Texas A&M University, College Station, Texas 77843, United States, and Department of Physics, Hubei University, Wuhan 430062, China
| | - Roland E. Allen
- Ministry of Education (MOE) Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, and Department of Applied Physics, Xi’an Jiaotong University, Xi’an 710049, China, Department of Physics, Texas A&M University, College Station, Texas 77843, United States, and Department of Physics, Hubei University, Wuhan 430062, China
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Liu J, Lam JWY, Jim CKW, Ng JCY, Shi J, Su H, Yeung KF, Hong Y, Faisal M, Yu Y, Wong KS, Tang BZ. Thiol−Yne Click Polymerization: Regio- and Stereoselective Synthesis of Sulfur-Rich Acetylenic Polymers with Controllable Chain Conformations and Tunable Optical Properties. Macromolecules 2010. [DOI: 10.1021/ma1023473] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jianzhao Liu
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
| | - Jacky W. Y. Lam
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
| | - Cathy K. W. Jim
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
| | - Jason C. Y. Ng
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
| | - Jianbing Shi
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
| | - Huimin Su
- Department of Chemistry, Institute of Molecular Functional Materials
| | - Kwok Fai Yeung
- Department of Chemistry, Institute of Molecular Functional Materials
| | - Yuning Hong
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
| | - Mahtab Faisal
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
| | - Yong Yu
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
| | - Kam Sing Wong
- Department of Chemistry, Institute of Molecular Functional Materials
| | - Ben Zhong Tang
- Fok Ying Tung Research Institute, The Hong Kong University of Science & Technology (HKUST), Nansha, Guangzhou, China
- Department of Physics
- Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
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Briney KA, Herman L, Boucher DS, Dunkelberger AD, Crim FF. The Influence of Vibrational Excitation on the Photoisomerization of trans-Stilbene in Solution. J Phys Chem A 2010; 114:9788-94. [DOI: 10.1021/jp102752f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kristin A. Briney
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Leslie Herman
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - David S. Boucher
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Adam D. Dunkelberger
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - F. Fleming Crim
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706
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Jiang CW, Xie RH, Li FL, Allen RE. Photocyclization of trans-stilbene induced by an ultrafast laser pulse. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.01.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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21
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Lin Z, Allen RE. Ultrafast equilibration of excited electrons in dynamical simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:485503. [PMID: 21832522 DOI: 10.1088/0953-8984/21/48/485503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In our density-functional-based simulations of materials responding to femtosecond-scale laser pulses, we have observed a potentially useful phenomenon: the excited electrons automatically equilibrate to a Fermi-Dirac distribution within ∼100 fs, solely because of their coupling to the nuclear motion, even though the resulting electronic temperature is one to two orders of magnitude higher than the kinetic temperature defined by the nuclear motion. Microscopic simulations like these can then provide the separate electronic and kinetic temperatures, chemical potentials, pressures, and nonhydrostatic stresses as input for studies on larger lengths and timescales.
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