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Pakhnyuk V, Onorato JW, Steiner EJ, Cohen TA, Luscombe CK. Enhanced miscibility and strain resistance of blended elastomer/π‐conjugated polymer composites through side chain functionalization towards stretchable electronics. POLYM INT 2019. [DOI: 10.1002/pi.5954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | - Jonathan W Onorato
- Department of Materials Science and Engineering University of Washington Seattle WA USA
| | - Emily J Steiner
- Department of Materials Science and Engineering University of Washington Seattle WA USA
| | - Theodore A Cohen
- Department of Materials Science and Engineering University of Washington Seattle WA USA
- Molecular Engineering and Sciences Institute University of Washington Seattle WA USA
| | - Christine K Luscombe
- Department of Chemistry University of Washington Seattle WA USA
- Department of Materials Science and Engineering University of Washington Seattle WA USA
- Molecular Engineering and Sciences Institute University of Washington Seattle WA USA
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2
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Freudenberg J, Jänsch D, Hinkel F, Bunz UHF. Immobilization Strategies for Organic Semiconducting Conjugated Polymers. Chem Rev 2018; 118:5598-5689. [DOI: 10.1021/acs.chemrev.8b00063] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jan Freudenberg
- Organisch-Chemisches Institut and Centre of Advanced Materials, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 225 and 270, 69120 Heidelberg, FRG
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, FRG
| | - Daniel Jänsch
- Organisch-Chemisches Institut and Centre of Advanced Materials, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 225 and 270, 69120 Heidelberg, FRG
- InnovationLab, Speyerer Str. 4, 69115 Heidelberg, FRG
| | - Felix Hinkel
- Organisch-Chemisches Institut and Centre of Advanced Materials, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 225 and 270, 69120 Heidelberg, FRG
| | - Uwe H. F. Bunz
- Organisch-Chemisches Institut and Centre of Advanced Materials, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 225 and 270, 69120 Heidelberg, FRG
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3
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Zhang J, Yang Y, Li Z, Zhang S, Sun Z. Dissociative photoionization of 1,2-dichloroethane in intense near-infrared femtosecond laser field. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2016.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Lin KC, Tsai PY. Molecular halogen elimination from halogen-containing compounds in the atmosphere. Phys Chem Chem Phys 2014; 16:7184-98. [PMID: 24622955 DOI: 10.1039/c3cp54828g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atmospheric halogen chemistry has drawn much attention, because the halogen atom (X) playing a catalytic role may cause severe stratospheric ozone depletion. Atomic X elimination from X-containing hydrocarbons is recognized as the major primary dissociation process upon UV-light irradiation, whereas direct elimination of the X2 product has been seldom discussed or remained a controversial issue. This account is intended to review the detection of X2 primary products using cavity ring-down absorption spectroscopy in the photolysis at 248 nm of a variety of X-containing compounds, focusing on bromomethanes (CH2Br2, CF2Br2, CHBr2Cl, and CHBr3), dibromoethanes (1,1-C2H4Br2 and 1,2-C2H4Br2) and dibromoethylenes (1,1-C2H2Br2 and 1,2-C2H2Br2), diiodomethane (CH2I2), thionyl chloride (SOCl2), and sulfuryl chloride (SO2Cl2), along with a brief discussion on acyl bromides (BrCOCOBr and CH2BrCOBr). The optical spectra, quantum yields, and vibrational population distributions of the X2 fragments have been characterized, especially for Br2 and I2. With the aid of ab initio calculations of potential energies and rate constants, the detailed photodissociation mechanisms may be comprehended. Such studies are fundamentally important to gain insight into the dissociation dynamics and may also practically help to assess the halogen-related environmental variation.
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Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
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5
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Huang YH, Lee YP. Infrared absorption of gaseous CH2BrOO detected with a step-scan Fourier-transform absorption spectrometer. J Chem Phys 2014; 141:164302. [DOI: 10.1063/1.4897982] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yu-Hsuan Huang
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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6
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Reid SA. When isomerisation is electron transfer: the intriguing story of the iso-halocarbons. INT REV PHYS CHEM 2014. [DOI: 10.1080/0144235x.2014.942548] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Yoon Y, Kim HJ, Cho CH, Kim S, Son HJ, Ko MJ, Kim H, Lee DK, Kim JY, Lee W, Kim BJ, Kim B. Carrier lifetime extension via the incorporation of robust hole/electron blocking layers in bulk heterojunction polymer solar cells. ACS APPLIED MATERIALS & INTERFACES 2014; 6:333-9. [PMID: 24256096 DOI: 10.1021/am404381e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report the achievement of a power conversion efficiency (PCE) improvement in P3HT:PCBM-based bulk-heterojunction type polymer solar cells using photocrosslinked P3HT (c-P3HT) as the electron blocking/hole extraction layer and titanium oxide nanoparticles (TiO2) as the hole blocking/electron extraction layer. Devices prepared with a 20 nm thick c-P3HT layer showed an improved PCE of 3.4% compared to devices prepared without the c-P3HT layer (PCE = 3.0%). This improvement was attributed to an extension in the carrier lifetime and an enhancement in the carrier mobility. The incorporation of the c-P3HT layer lengthened (by more than a factor of 2) the carrier lifetime and increased (by a factor of 5) the hole mobility. These results suggest that the c-P3HT layer not only prevented non-geminate recombination but it also improved carrier transport. The PCE was further improved to 4.0% through the insertion of a TiO2 layer that acted as an effective hole-blocking layer at the interface between the photoactive layer and the cathode. This work demonstrates that the incorporation of solution-processable hole and electron blocking/extraction layers offers an effective means for preventing nongeminate recombination at the interfaces between a photoactive layer and an electrode in bulk-heterojunction-type polymer solar cells.
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Affiliation(s)
- Youngwoon Yoon
- Photo-electronic Hybrids Research Center, Korea Institute of Science and Technology , Seoul 136-791, Republic of Korea
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8
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Wu H, Zhang S, Yang Y, Sun S, Zhang J, Deng L, Jia T, Wang Z, Sun Z. Coulomb explosion and dissociative ionization of 1,2-dibromoethane under an intense femtosecond laser field. RSC Adv 2014. [DOI: 10.1039/c4ra06121g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Coulomb explosion and dissociative ionization of 1,2-dibromoethane are experimentally investigated in a near-infrared (800 nm) femtosecond laser field by dc-slice imaging technology.
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Affiliation(s)
- Hua Wu
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Shian Zhang
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Yan Yang
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
- State Key Laboratory of High Field Laser Physics
| | - Shengzhi Sun
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Jian Zhang
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Li Deng
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Tianqing Jia
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Zugeng Wang
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
| | - Zhenrong Sun
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062, P. R. China
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9
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Kalume A, George L, Cunningham N, Reid SA. Case of the Missing Isomer: Pathways for Molecular Elimination in the Photoinduced Decomposition of 1,1-Dibromoethane. J Phys Chem A 2013; 117:11915-23. [DOI: 10.1021/jp403114s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Aimable Kalume
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881,
United States
| | - Lisa George
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881,
United States
| | - Nicole Cunningham
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881,
United States
| | - Scott A. Reid
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881,
United States
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10
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Rissanen MP, Eskola AJ, Timonen RS. Kinetics of the brominated alkyl radical (CHBr2
, CH3
CHBr) reactions with NO2
in the temperature range 250-480 K. INT J CHEM KINET 2012. [DOI: 10.1002/kin.20725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Chin CH, Lee SH. Comparison of two-body and three-body decomposition of ethanedial, propanal, propenal, n-butane, 1-butene, and 1,3-butadiene. J Chem Phys 2012; 136:024308. [DOI: 10.1063/1.3675682] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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12
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Lin JL, Lin YS, Shih JJ, Kuo KH, Lin SK, Wu TS, Shiu MY. 1,2-Dibromoethane on Cu(100): Bonding structure and transformation to C 2H 4. J Chem Phys 2011; 135:064706. [DOI: 10.1063/1.3624348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Kalume A, George L, El-Khoury PZ, Tarnovsky AN, Reid SA. Spectroscopic and Computational Studies of the Laser Photolysis of Matrix Isolated 1,2-Dibromoethanes: Formation and Fate of the Bromoethyl Radicals. J Phys Chem A 2010; 114:9919-26. [DOI: 10.1021/jp103953w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Kalume
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43402
| | - L. George
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43402
| | - P. Z. El-Khoury
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43402
| | - A. N. Tarnovsky
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43402
| | - S. A. Reid
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43402
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14
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El-Khoury PZ, Pal SK, Mereshchenko AS, Tarnovsky AN. The formation and back isomerization of iso-H2C–Br–Br on a 100-ps time scale following 255-nm excitation of CH2Br2 in acetonitrile. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.04.065] [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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15
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Fang Q, Zhang F, Shen L, Fang WH, Luo Y. Photodissociation of phosgene: Theoretical evidence for the ultrafast and synchronous concerted three-body process. J Chem Phys 2009; 131:164306. [DOI: 10.1063/1.3253048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Lee HL, Lee PC, Tsai PY, Lin KC, Kuo HH, Chen PH, Chang AHH. Photodissociation of dibromoethanes at 248 nm: An ignored channel of Br[sub 2] elimination. J Chem Phys 2009; 130:184308. [DOI: 10.1063/1.3130768] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Liu Y, Xiao H, Sun M, Fang W. Spin-orbitAb initioinvestigation of the photodissociation of dibromomethane in the gas and solution phases. J Comput Chem 2008; 29:2513-9. [DOI: 10.1002/jcc.21008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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18
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Lee KS, Yeon KY, Jung KH, Kim SK. Direct observation of the primary and secondary C-Br bond cleavages from the 1,2-dibromopropane photodissociation at 234 and 265 nm using the velocity map ion imaging technique. J Phys Chem A 2008; 112:9312-7. [PMID: 18665578 DOI: 10.1021/jp8022666] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photodissociation dynamics of 1,2-dibromopropane has been investigated at 234 and 265 nm by using the velocity map ion imaging method. At both pump energies, a single Gaussian-shaped speed distribution is observed for the Br*((2)P(1/2)) fragment, whereas at least three velocity components are found to be existent for the Br((2)P(3/2)) product. The secondary C-Br bond cleavage of the bromopropyl radical which is energized from the ultrafast primary C-Br bond rupture should be responsible for the multicomponent translational energy distribution at the low kinetic energy region of Br((2)P(3/2)). The recoil anisotropy parameter (beta) of the fragment from the primary C-Br bond dissociation is measured to be 0.53 (0.49) and 1.26 (1.73) for Br((2)P(3/2)) and Br*((2)P(1/2)), respectively, at 234 (265) nm. The beta value of Br((2)P(3/2)) from the secondary C-Br bond dissociation event at 265 nm is found to be 0.87, reflecting the fact that the corresponding Br((2)P(3/2)) fragment carried the initial vector component of the bromopropyl radical produced from the primary bond dissociation event. Density functional theory has been used to calculate energetics involved both in the primary and in the secondary C-Br bond dissociation dynamics.
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Affiliation(s)
- Kyoung-Seok Lee
- Department of Chemistry and School of Molecular Science (BK21), KAIST, Daejeon 305-701, Republic of Korea
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19
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Kinetics of the R+HBr⇄RH+Br (CH3CHBr, CHBr2 or CDBr2) equilibrium. Thermochemistry of the CH3CHBr and CHBr2 radicals. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Ji L, Tang Y, Zhu R, Wei Z, Zhang B. Photodissociation dynamics of CH(2)Br(2) near 234 and 267 nm. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 67:273-80. [PMID: 17267280 DOI: 10.1016/j.saa.2006.07.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 07/05/2006] [Accepted: 07/05/2006] [Indexed: 05/13/2023]
Abstract
The photodissociation dynamics of CH(2)Br(2) was investigated near 234 and 267 nm. A two-dimensional photofragment ion velocity imaging technique coupled with a [2+1] resonance-enhanced multiphoton (REMPI) ionization scheme was utilized to obtain the angular and translational energy distributions of the nascent Br ((2)P(3/2)) and Br* ((2)P(1/2)) atoms. The obtained translational energy distributions of Br and Br* are found consist of two components which should be come from the radical channel and secondary dissociation process, respectively. It is suggested that the symmetry reduction from C(2v) to C(s) during photodissociation invokes a non-adiabatic coupling between the 2B(1) and A(1) states. Consequently, the higher internal energy distribution of Br channel than Br* formation channel and the broader translational energy distribution of the former are presumed correlate with a variety of vibrational excitation disposal at the crossing point resulting from the larger non-adiabatic crossing from 2B(1) to A(1) state than the reverse crossing. Moreover, the measured anisotropy parameter beta indicate that fragments recoil along the Br-Br direction mostly in the photodissociation.
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Affiliation(s)
- Lei Ji
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
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21
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Wei PY, Chang YP, Lee WB, Hu Z, Huang HY, Lin KC, Chen KT, Chang AHH. 248nm photolysis of CH2Br2 by using cavity ring-down absorption spectroscopy: Br2 molecular elimination at room temperature. J Chem Phys 2006; 125:133319. [PMID: 17029472 DOI: 10.1063/1.2218514] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Following photodissociation of CH2Br2 at 248 nm, Br2 molecular elimination is detected by using a tunable laser beam, as crossed perpendicular to the photolyzing laser beam in a ring-down cell, probing the Br2 fragment in the B 3Piou+ -X 1Sigmag+ transition. The nascent vibrational population is obtained, yielding a population ratio of Br2(v = 1)Br2(v = 0) to be 0.7 +/- 0.2. The quantum yield for the Br2 elimination reaction is determined to be 0.2 +/- 0.1. Nevertheless, when CH2Br2 is prepared in a supersonic molecular beam under cold temperature, photofragmentation gives no Br2 detectable in a time-of-flight mass spectrometer. With the aid of ab initio potential energy calculations, a plausible pathway is proposed. Upon excitation to the 1B1 or 3B1 state, C-Br bond elongation may change the molecular symmetry of Cs and enhance the resultant 1 1,3A'-X 1A' (or 1 1,3B1-X 1A1 as C2v is used) coupling to facilitate the process of internal conversion, followed by asynchronous concerted photodissociation. Temperature dependence measurements lend support to the proposed pathway.
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Affiliation(s)
- Pei-Ying Wei
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
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22
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Roeterdink WG, Rijs AM, Janssen MHM. Imaging of Ultrafast Molecular Elimination Reactions. J Am Chem Soc 2005; 128:576-80. [PMID: 16402845 DOI: 10.1021/ja055658x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast molecular elimination reactions are studied using the velocity map ion imaging technique in combination with femtosecond pump-probe laser excitation. A pump laser is used to initiate the dissociative reaction, and after a predetermined time delay a probe laser "interrogates" the molecular system. Ionic fragments are detected with a two-dimensional velocity map imaging detector providing detailed information about the energetic and vectorial properties of mass selected photofragments. In this paper we discuss the ultrafast elimination of molecular iodine, I(2), from IF(2)C-CF(2)I, where the iodine atoms originate from neighboring carbon atoms. By varying the femtosecond delay between pump and probe pulse, it is found that elimination of molecular iodine is a concerted process, although the two carbon-iodine bonds are not broken synchronously. Energetic considerations suggest that the crucial step in this fragmentation process is an electron transfer between the two iodine atoms in the parent molecule, which leads to Coulombic attraction and the creation of an ion-pair state in the molecular iodine fragment.
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Affiliation(s)
- Wim G Roeterdink
- Laser Centre and Department of Chemistry, Vrije Universiteit de Boelelaan 1083, Amsterdam, The Netherlands
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Tang Y, Ji L, Zhu R, Wei Z, Zhang B. Photodissociation Study of Ethyl Bromide in the Ultraviolet Range by the Ion-Velocity Imaging Technique. Chemphyschem 2005; 6:2137-44. [PMID: 16208756 DOI: 10.1002/cphc.200500246] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The photodissociation of ethyl bromide has been studied in the wavelength range of 231-267 nm by means of the ion velocity imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization (REMPI) scheme. The velocity distributions for the Br ((2)P(1/2)) (denoted Br*) and Br ((2)P(3/2)) (denoted Br) fragments are determined, and each can be well-fitted by a narrow single-peaked Gaussian curve, which suggests that the bromine fragments are generated as a result of direct dissociation via repulsive potential-energy surfaces (PES). The recoil anisotropy results show that beta(Br) and beta(Br*) decrease with the wavelength, and the angular distributions of Br* suggest a typical parallel transition. The product relative quantum yields at two different wavelengths are Phi(234nm)(Br*)=0.17 and Phi(267nm)(Br*)=0.31. The relative fractions of each potential surface for the bromine fragments' production at 234 and 267 nm reveal the existence of a curve crossing between the (3)Q(0) and (1)Q(1) potential surfaces, and the probability of curve crossing decreases with the laser wavelength. The symmetry reduction of C(2)H(5)Br from C(3v) to C(s) invokes a nonadiabatic coupling between the (3)Q(0) and (1)Q(1) states, and with higher energy photons, the probability that crossing will take place increases.
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Affiliation(s)
- Ying Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
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Wang Y, Zhang S, Tang B, Zheng Q, Zhang B. One-color two-photon mass-analyzed threshold ionization spectroscopy of 2-bromopropane. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.06.097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Lee YR, Chen CC, Lin SM. A concerted three-body formation X+Y+C2H4 in the photodissociation of CH2XCH2Y (X,Y=Br,Cl) at 193 nm. J Chem Phys 2004; 120:1223-30. [PMID: 15268247 DOI: 10.1063/1.1633262] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The photodissociation of CH2XCH2Y (X,Y=Br,Cl) through absorption of 193 nm photons was investigated using product translational spectroscopy. No stable CH2BrCH2 or CH2ClCH2 was detected. The recorded time-of-flight spectra indicate that these internally excited radicals dissociated into Y+C2H4 in a concerted reaction with the first C-X bond rupture. Product anisotropy implies that the overall reaction time for three-body formation is in a fraction of rotational period. According to an asynchronous concerted reaction model, the measured spectra were simulated with product translational energy distributions coupled by asymmetric angular distributions. For the mixed halide, CH2BrCH2Cl, triple products Br+Cl+C2H4 can be originated from the cleavage of either the C-Br bond or the C-Cl bond. The results are discussed and where appropriate, comparisons with previous investigations of the related molecules are included.
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Affiliation(s)
- Ya-Rong Lee
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan P.O. Box 23-166, Taipei, Taiwan
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