1
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Barak A, Dhiman N, Sturm F, Rauch F, Lakshmanna YA, Findlay KS, Beeby A, Marder TB, Umapathy S. Excited‐State Intramolecular Charge‐Transfer Dynamics in 4‐Dimethylamino‐4’‐Cyanodiphenylacetylene: An Ultrafast Raman Loss Spectroscopic Perspective. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202200146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Arvind Barak
- Indian Institute of Science Department of Inorganic and Physical Chemistry 560012 Bangalore INDIA
| | - Nishant Dhiman
- Indian Institute of Science Department of Inorganic and Physical Chemistry 560012 Bangalore INDIA
| | - Floriane Sturm
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron (ICB) GERMANY
| | - Florian Rauch
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron (ICB) GERMANY
| | - Yapamanu Adithya Lakshmanna
- Indian Institute of Science Education and Research Thiruvananthapuram School of Chemistry 695551 Thiruvananthapuram INDIA
| | - Karen S. Findlay
- University of Durham: Durham University Department of Chemistry UNITED KINGDOM
| | - Andrew Beeby
- University of Durham: Durham University Department of Chemistry UNITED KINGDOM
| | - Todd B. Marder
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron (ICB) GERMANY
| | - Siva Umapathy
- Indian Institute of Science Dept. of Inorganic and physical chemistry Raman avenue 560012 Bangalore INDIA
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2
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Dobryakov AL, Krohn OA, Quick M, Ioffe I, Kovalenko SA. Positive and Negative Signal and Line-Shape in Stimulated Raman Spectroscopy: Resonance Femtosecond Raman Spectra of Diphenylbutadiene. J Chem Phys 2022; 156:084304. [DOI: 10.1063/5.0075116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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3
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Wei J, Wu Y, Pu R, Shi L, Jiang J, Du J, Guo Z, Huang Y, Liu W. Tracking Ultrafast Structural Dynamics in a Dual-Emission Anti-Kasha-Active Fluorophore Using Femtosecond Stimulated Raman Spectroscopy. J Phys Chem Lett 2021; 12:4466-4473. [PMID: 33955767 DOI: 10.1021/acs.jpclett.1c00202] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The anti-Kasha process provides the possibility of using high-energy excited states to develop novel applications. Our previous research (Nature communications, 2020, 11, 793) has demonstrated a dual-emission anti-Kasha-active fluorophore for bioimaging application, which exhibits near-infrared emissions from the S1 state and visible anti-Kasha emissions from the S2 state. Here, we applied tunable blue-side femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption spectroscopy, assisted by quantum calculations, to reveal the anti-Kasha dual emission mechanism, in which the emergence of two fluorescing states is due to the retardation of internal conversion from the S2 state to the S1 state. It has been demonstrated that the facts of anti-Kasha high-energy emission are commonly attributed to a large energy gap between the two excited states, leading to a decrease in the internal conversion rate due to a poor Franck-Condon factor. In this study, analysis of the calculation and FSRS experimental results provide us further insight into the dual-emission anti-Kasha mechanism, where the observation of hydrogen out-of-plane Raman modes from FSRS suggested that, in addition to the energy-gap law, the initial photoinduced molecular conformational change plays a key role in influencing the rate of internal conversion.
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Affiliation(s)
- Jingle Wei
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
| | - Yuexia Wu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
| | - Ruihua Pu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
| | - Limin Shi
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jiaming Jiang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Juan Du
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Zhiqian Guo
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yifan Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
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4
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Fang C, Tang L, Chen C. Unveiling coupled electronic and vibrational motions of chromophores in condensed phases. J Chem Phys 2019; 151:200901. [PMID: 31779327 DOI: 10.1063/1.5128388] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The quest for capturing molecular movies of functional systems has motivated scientists and engineers for decades. A fundamental understanding of electronic and nuclear motions, two principal components of the molecular Schrödinger equation, has the potential to enable the de novo rational design for targeted functionalities of molecular machines. We discuss the development and application of a relatively new structural dynamics technique, femtosecond stimulated Raman spectroscopy with broadly tunable laser pulses from the UV to near-IR region, in tracking the coupled electronic and vibrational motions of organic chromophores in solution and protein environments. Such light-sensitive moieties hold broad interest and significance in gaining fundamental knowledge about the intramolecular and intermolecular Hamiltonian and developing effective strategies to control macroscopic properties. Inspired by recent experimental and theoretical advances, we focus on the in situ characterization and spectroscopy-guided tuning of photoacidity, excited state proton transfer pathways, emission color, and internal conversion via a conical intersection.
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Affiliation(s)
- Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Longteng Tang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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5
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Takaya T, Enokida I, Furukawa Y, Iwata K. Direct Observation of Structure and Dynamics of Photogenerated Charge Carriers in Poly(3-hexylthiophene) Films by Femtosecond Time-Resolved Near-IR Inverse Raman Spectroscopy. Molecules 2019; 24:molecules24030431. [PMID: 30691007 PMCID: PMC6384712 DOI: 10.3390/molecules24030431] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/18/2019] [Accepted: 01/22/2019] [Indexed: 11/16/2022] Open
Abstract
The initial charge separation process of conjugated polymers is one of the key factors for understanding their conductivity. The structure of photogenerated transients in conjugated polymers can be observed by resonance Raman spectroscopy in the near-IR region because they exhibit characteristic low-energy transitions. Here, we investigate the structure and dynamics of photogenerated transients in a regioregular poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend film, as well as in a pristine P3HT film, using femtosecond time-resolved resonance inverse Raman spectroscopy in the near-IR region. The transient inverse Raman spectrum of the pristine P3HT film at 50 ps suggests coexistence of neutral and charged excitations, whereas that of the P3HT:PCBM blend film at 50 ps suggests formation of positive polarons with a different structure from those in an FeCl3-doped P3HT film. Time-resolved near-IR inverse Raman spectra of the blend film clearly show the absence of charge separation between P3HT and PCBM within the instrument response time of our spectrometer, while they indicate two independent pathways of the polaron formation with time constants of 0.3 and 10 ps.
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Affiliation(s)
- Tomohisa Takaya
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
| | - Ippei Enokida
- Department of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Yukio Furukawa
- Department of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Koichi Iwata
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
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6
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Mathew R, Kayal S, Yapamanu AL. Excited state structural dynamics of 4-cyano-4′-hydroxystilbene: deciphering the signatures of proton-coupled electron transfer using ultrafast Raman loss spectroscopy. Phys Chem Chem Phys 2019; 21:22409-22419. [DOI: 10.1039/c9cp02923k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photo-initiated proton-coupled electron transfer process in the 4-cyano-4′-hydroxystilbene–tert-butylamine adduct strongly affects the excited-state structural dynamics of CHSB.
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Affiliation(s)
- Reshma Mathew
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram
- Thiruvananthapuram 695551
- India
| | - Surajit Kayal
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore 560012
- India
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7
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Jana S, Yapamanu AL, Umapathy S. Unraveling structural dynamics in isoenergetic excited S1 and multi-excitonic 1(TT) states of 9,10-bis(phenylethynyl)anthracene (BPEA) in solution via ultrafast Raman loss spectroscopy. Phys Chem Chem Phys 2019; 21:14341-14349. [DOI: 10.1039/c8cp06658b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ultrafast Raman loss spectroscopy provides a direct evidence for the structural changes that occur during the evolution from the S1 to the 1(TT) state of BPEA in solution.
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Affiliation(s)
- Sanjib Jana
- Department of Instrumentation and Applied Physics
- Bangalore 560012
- India
| | | | - Siva Umapathy
- Department of Instrumentation and Applied Physics
- Bangalore 560012
- India
- Department of Inorganic and Physical Chemistry and Applied Physics
- Bangalore 560012
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8
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Hall CR, Romanov AS, Bochmann M, Meech SR. Ultrafast Structure and Dynamics in the Thermally Activated Delayed Fluorescence of a Carbene-Metal-Amide. J Phys Chem Lett 2018; 9:5873-5876. [PMID: 30230847 DOI: 10.1021/acs.jpclett.8b02797] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thermally activated delayed fluorescence has enormous potential for the development of efficient light emitting diodes. A recently discovered class of molecules (the carbene-metal-amides, CMAs) are exceptionally promising as they combine the small singlet-triplet energy gap required for thermal activation with a large transition moment for emission. Calculations suggest excited state structural dynamics modulate the critical coupling between singlet and triplet, but they disagree on the nature of those dynamics. Here we report ultrafast time-resolved transient absorption and Raman studies of CMA photodynamics. The measurements reveal complex structural evolution following intersystem crossing on the tens to hundreds of picoseconds time scale, and a change in the low-frequency vibrational spectrum between singlet and triplet states. The latter is assigned to changes in Raman active modes localized on the metal center.
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Affiliation(s)
| | | | - Manfred Bochmann
- School of Chemistry , University of East Anglia , Norwich NR4 7TJ , U.K
| | - Stephen R Meech
- School of Chemistry , University of East Anglia , Norwich NR4 7TJ , U.K
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9
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Chen C, Zhu LD, Fang C. Femtosecond stimulated Raman line shapes: Dependence on resonance conditions of pump and probe pulses. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1805125] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Liang-dong Zhu
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
- Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, Oregon, 97331-6507, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
- Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, Oregon, 97331-6507, USA
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10
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Kayal S, Roy K, Lakshmanna YA, Umapathy S. Probing the effect of solvation on photoexcited 2-(2′-hydroxyphenyl)benzothiazole via ultrafast Raman loss spectroscopic studies. J Chem Phys 2018; 149:044310. [DOI: 10.1063/1.5028274] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Surajit Kayal
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Khokan Roy
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Y. Adithya Lakshmanna
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Siva Umapathy
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India
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11
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Fang C, Tang L, Oscar BG, Chen C. Capturing Structural Snapshots during Photochemical Reactions with Ultrafast Raman Spectroscopy: From Materials Transformation to Biosensor Responses. J Phys Chem Lett 2018; 9:3253-3263. [PMID: 29799757 DOI: 10.1021/acs.jpclett.8b00373] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemistry studies the composition, structure, properties, and transformation of matter. A mechanistic understanding of the pertinent processes is required to translate fundamental knowledge into practical applications. The current development of ultrafast Raman as a powerful time-resolved vibrational technique, particularly femtosecond stimulated Raman spectroscopy (FSRS), has shed light on the structure-energy-function relationships of various photosensitive systems. This Perspective reviews recent work incorporating optical innovations, including the broad-band up-converted multicolor array (BUMA) into a tunable FSRS setup, and demonstrates its resolving power to watch metal speciation and photolysis, leading to high-quality thin films, and fluorescence modulation of chimeric protein biosensors for calcium ion imaging. We discuss advantages of performing FSRS in the mixed time-frequency domain and present strategies to delineate mechanisms by tracking low-frequency modes and systematically modifying chemical structures with specific functional groups. These unique insights at the chemical-bond level have started to enable the rational design and precise control of functional molecular machines in optical, materials, energy, and life sciences.
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Affiliation(s)
- Chong Fang
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Longteng Tang
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Breland G Oscar
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Cheng Chen
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
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12
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Bilal SM, Kayal S, Sanju KS, Adithya Lakshmanna Y. Femtosecond Time-Resolved Raman Spectroscopy Reveals Structural Evidence for meta Effect in Stilbenols. J Phys Chem A 2018; 122:4601-4608. [PMID: 29683672 DOI: 10.1021/acs.jpca.7b12339] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The meta effect in substituted aromatics plays a crucial role in their excited-state photophysical properties. Meta-substituted hydroxyarenes such as naphthols, stilbenols, and chromophoric constituents of green fluorescent proteins show unusual photoacidity and enhanced fluorescence lifetime and quantum yield when compared to their para-derivatives. Variation in the excited state features of the meta-derivatives when compared to the para-derivatives in stilbenols has been attributed to the enhanced torsional barrier for interconversion between the planar and the twisted perpendicular forms. Herein, we employed femtosecond time-resolved Raman spectroscopy to provide the direct structural evidence for the enhanced torsional barrier in meta-stilbenol. The Raman band profiles of the olefinic C═C stretch related to the torsional motion are found to decay with time constants of ∼750 and ∼13 ps in meta-stilbenol and para-stilbenol respectively, unraveling the structural evidence for the observed enhanced photoacidity originating from enhanced rates of excited-state proton transfer. Further, time-resolved fluorescence measurements are performed to elucidate the relaxation pathways of the excited states of the stilbenols.
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Affiliation(s)
- Syed M Bilal
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Vithura, Thiruvananthapuram 695551 , India
| | - Surajit Kayal
- Department of Inorganic and Physical Chemistry , Indian Institute of Science , Bangalore 560012 , India
| | - Krishnankutty S Sanju
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Vithura, Thiruvananthapuram 695551 , India
| | - Y Adithya Lakshmanna
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Vithura, Thiruvananthapuram 695551 , India
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13
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Hall CR, Browne WR, Feringa BL, Meech SR. Mapping the Excited‐State Potential Energy Surface of a Photomolecular Motor. Angew Chem Int Ed Engl 2018; 57:6203-6207. [DOI: 10.1002/anie.201802126] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Indexed: 01/05/2023]
Affiliation(s)
| | - Wesley R. Browne
- Molecular Inorganic Chemistry Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen Netherlands
| | - Ben L. Feringa
- Synthetic Organic Chemistry Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen Netherlands
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14
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Hall CR, Browne WR, Feringa BL, Meech SR. Mapping the Excited‐State Potential Energy Surface of a Photomolecular Motor. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
| | - Wesley R. Browne
- Molecular Inorganic Chemistry Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen Netherlands
| | - Ben L. Feringa
- Synthetic Organic Chemistry Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen Netherlands
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15
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Kayal S, Roy K, Umapathy S. Femtosecond coherent nuclear dynamics of excited tetraphenylethylene: Ultrafast transient absorption and ultrafast Raman loss spectroscopic studies. J Chem Phys 2018; 148:024301. [DOI: 10.1063/1.5008726] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Surajit Kayal
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Khokan Roy
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Siva Umapathy
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India
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16
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Hart SM, Silva WR, Frontiera RR. Femtosecond stimulated Raman evidence for charge-transfer character in pentacene singlet fission. Chem Sci 2017; 9:1242-1250. [PMID: 29675170 PMCID: PMC5885776 DOI: 10.1039/c7sc03496b] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 12/12/2017] [Indexed: 12/22/2022] Open
Abstract
Evidence for transient anionic and cationic species in singlet fission is given by ultrafast Raman measurements.
Singlet fission is a spin-allowed process in which an excited singlet state evolves into two triplet states. We use femtosecond stimulated Raman spectroscopy, an ultrafast vibrational technique, to follow the molecular structural evolution during singlet fission in order to determine the mechanism of this process. In crystalline pentacene, we observe the formation of an intermediate characterized by pairs of excited state peaks that are red- and blue-shifted relative to the ground state features. We hypothesize that these features arise from the formation of cationic and anionic species due to partial transfer of electron density from one pentacene molecule to a neighboring molecule. These observations provide experimental evidence for the role of states with significant charge-transfer character which facilitate the singlet fission process in pentacene. Our work both provides new insight into the singlet fission mechanism in pentacene and demonstrates the utility of structurally-sensitive time-resolved spectroscopic techniques in monitoring ultrafast processes.
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Affiliation(s)
- Stephanie M Hart
- Department of Chemistry , University of Minnesota , Minneapolis , MN 55455 , USA .
| | - W Ruchira Silva
- Department of Chemistry , University of Minnesota , Minneapolis , MN 55455 , USA .
| | - Renee R Frontiera
- Department of Chemistry , University of Minnesota , Minneapolis , MN 55455 , USA .
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17
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Chen C, Liu W, Baranov MS, Baleeva NS, Yampolsky IV, Zhu L, Wang Y, Shamir A, Solntsev KM, Fang C. Unveiling Structural Motions of a Highly Fluorescent Superphotoacid by Locking and Fluorinating the GFP Chromophore in Solution. J Phys Chem Lett 2017; 8:5921-5928. [PMID: 29148819 DOI: 10.1021/acs.jpclett.7b02661] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Superphotoacidity involves ultrafast proton motions implicated in numerous chemical and biological processes. We used conformational locking and strategic addition of electron-withdrawing substituents to synthesize a new GFP chromophore analogue: p-HO-3,5-diF-BDI:BF2 (diF). It is highly fluorescent and exhibits excited-state proton transfer (ESPT) in various solvents, placing it among the strongest photoacids. Tunable femtosecond stimulated Raman spectroscopy with unique resonance conditions and transient absorption are complementarily employed to elucidate the structural basis for superphotoacidity. We reveal a multistep ESPT reaction from diF to methanol with an initial proton dissociation on the ∼600 fs time scale that forms a charge-separated state, stabilized by solvation, and followed by a diffusion-controlled proton transfer on the ∼350 ps time scale. A ∼1580 cm-1 phenolic ring motion is uncovered to accompany ESPT before 1 ps. This study provides a vivid movie of the photoinduced proton dissociation of a superphotoacid with bright fluorescence, effectively bridging fundamental mechanistic insights to precise control of macroscopic functions.
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Weimin Liu
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Ilia V Yampolsky
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Pirogov Russian National Research Medical University , Ostrovitianov 1, Moscow 117997, Russia
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Yanli Wang
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Alexandra Shamir
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - Kyril M Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97331, United States
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18
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Oscar BG, Chen C, Liu W, Zhu L, Fang C. Dynamic Raman Line Shapes on an Evolving Excited-State Landscape: Insights from Tunable Femtosecond Stimulated Raman Spectroscopy. J Phys Chem A 2017; 121:5428-5441. [DOI: 10.1021/acs.jpca.7b04404] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Breland G. Oscar
- Department
of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Cheng Chen
- Department
of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Weimin Liu
- Department
of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Liangdong Zhu
- Department
of Physics, Oregon State University, 301 Weniger Hall, Corvallis, Oregon 97331, United States
| | - Chong Fang
- Department
of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
- Department
of Physics, Oregon State University, 301 Weniger Hall, Corvallis, Oregon 97331, United States
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19
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Liu W, Tang L, Oscar BG, Wang Y, Chen C, Fang C. Tracking Ultrafast Vibrational Cooling during Excited-State Proton Transfer Reaction with Anti-Stokes and Stokes Femtosecond Stimulated Raman Spectroscopy. J Phys Chem Lett 2017; 8:997-1003. [PMID: 28195486 DOI: 10.1021/acs.jpclett.7b00322] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Energy dissipation following photoexcitation is foundational to photophysics and chemistry. Consequently, understanding such processes on molecular time scales holds paramount importance. Femtosecond stimulated Raman spectroscopy (FSRS) has been used to study the molecular structure-function relationships but usually on the Stokes side. Here, we perform both Stokes and anti-Stokes FSRS to track energy dissipation and excited-state proton transfer (ESPT) for the photoacid pyranine in aqueous solution. We reveal biphasic vibrational cooling on fs-ps time scales during ESPT. Characteristic low-frequency motions (<800 cm-1) exhibit initial energy dissipation (∼2 ps) that correlates with functional events of forming contact ion pairs via H-bonds between photoacid and water, which lengthens to ∼9 ps in methanol where ESPT is inhibited. The interplay between photoinduced dissipative and reactive channels is implied. Thermal cooling to bulk solvent occurs on the ∼50 ps time scale. These results demonstrate the combined Stokes and anti-Stokes FSRS as a powerful toolset to elucidate structural dynamics.
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Affiliation(s)
- Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University , Pudong, Shanghai 201210, People's Republic of China
| | - Longteng Tang
- Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States
| | - Breland G Oscar
- Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States
| | - Yanli Wang
- Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States
| | - Cheng Chen
- Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States
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20
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Roy K, Kayal S, Ariese F, Beeby A, Umapathy S. Mode specific excited state dynamics study of bis(phenylethynyl)benzene from ultrafast Raman loss spectroscopy. J Chem Phys 2017; 146:064303. [DOI: 10.1063/1.4975174] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Khokan Roy
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Surajit Kayal
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Freek Ariese
- On leave from LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
| | - Andrew Beeby
- Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom
| | - Siva Umapathy
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
- On leave from LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
- Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India
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21
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Dietze DR, Mathies RA. Femtosecond Stimulated Raman Spectroscopy. Chemphyschem 2016; 17:1224-51. [DOI: 10.1002/cphc.201600104] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel R. Dietze
- Department of Chemistry; University of California in Berkeley; CA Berkeley 94720 USA
| | - Richard A. Mathies
- Department of Chemistry; University of California in Berkeley; CA Berkeley 94720 USA
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22
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Wavelength dependent resonance Raman band intensity of broadband stimulated Raman spectroscopy of malachite green in ethanol. J Chem Phys 2015; 142:114201. [DOI: 10.1063/1.4914188] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Kumar S, Matange N, Umapathy S, Visweswariah SS. Linking carbon metabolism to carotenoid production in mycobacteria using Raman spectroscopy. FEMS Microbiol Lett 2015; 362:1-6. [DOI: 10.1093/femsle/fnu048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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24
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Parker AW, Bisby RH, Greetham GM, Kukura P, Scherer KM, Towrie M. Ultrafast vibrational spectroscopic studies on the photoionization of the α-tocopherol analogue trolox C. J Phys Chem B 2014; 118:12087-97. [PMID: 25260188 DOI: 10.1021/jp505113k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The initial events after photoexcitation and photoionization of α-tocopherol (vitamin E) and the analogue Trolox C have been studied by femtosecond stimulated Raman spectroscopy, transient absorption spectroscopy and time-resolved infrared spectroscopy. Using these techniques it was possible to follow the formation and decay of the excited state, neutral and radical cation radicals and the hydrated electron that are produced under the various conditions examined. α-Tocopherol and Trolox C in methanol solution appear to undergo efficient homolytic dissociation of the phenolic -OH bond to directly produce the tocopheroxyl radical. In contrast, Trolox C photochemistry in neutral aqueous solutions involves intermediate formation of a radical cation and the hydrated electron which undergo geminate recombination within 100 ps in competition with deprotonation of the radical cation. The results are discussed in relation to recently proposed mechanisms for the reaction of α-tocopherol with peroxyl radicals, which represents the best understood biological activity of this vitamin.
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Affiliation(s)
- Anthony W Parker
- Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Harwell Oxford , Didcot, Oxfordshire, OX11 0QX, U.K
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25
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Balakrishnan G, Soldatova A, Reid PJ, Spiro TG. Ultrafast charge transfer in nickel phthalocyanine probed by femtosecond Raman-induced Kerr effect spectroscopy. J Am Chem Soc 2014; 136:8746-54. [PMID: 24841906 PMCID: PMC4136751 DOI: 10.1021/ja503541v] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Indexed: 12/19/2022]
Abstract
The recently developed technique of femtosecond stimulated Raman spectroscopy, and its variant, femtosecond Raman-induced Kerr effect spectroscopy (FRIKES), offer access to ultrafast excited-state dynamics via structurally specific vibrational spectra. We have used FRIKES to study the photoexcitation dynamics of nickel(II) phthalocyanine with eight butoxy substituents, NiPc(OBu)8. NiPc(OBu)8 is reported to have a relatively long-lived ligand-to-metal charge-transfer (LMCT) state, an essential characteristic for efficient electron transfer in photocatalysis. Following photoexcitation, vibrational transitions in the FRIKES spectra, assignable to phthalocyanine ring modes, evolve on the femtosecond to picosecond time scales. Correlation of ring core size with the frequency of the ν10 (asymmetric C-N stretching) mode confirms the identity of the LMCT state, which has a ∼500 ps lifetime, as well as that of a precursor d-d excited state. An even earlier (∼0.2 ps) transient is observed and tentatively assigned to a higher-lying Jahn-Teller-active LMCT state. This study illustrates the power of FRIKES spectroscopy in elucidating ultrafast molecular dynamics.
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Affiliation(s)
- Gurusamy Balakrishnan
- Department of Chemistry, University
of Washington, Seattle, Washington 98195, United States
| | - Alexandra
V. Soldatova
- Department of Chemistry, University
of Washington, Seattle, Washington 98195, United States
| | - Philip J. Reid
- Department of Chemistry, University
of Washington, Seattle, Washington 98195, United States
| | - Thomas G. Spiro
- Department of Chemistry, University
of Washington, Seattle, Washington 98195, United States
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26
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Velarde L, Wang HF. Unified treatment and measurement of the spectral resolution and temporal effects in frequency-resolved sum-frequency generation vibrational spectroscopy (SFG-VS). Phys Chem Chem Phys 2014; 15:19970-84. [PMID: 24076622 DOI: 10.1039/c3cp52577e] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The lack of understanding of the temporal effects and the restricted ability to control experimental conditions in order to obtain intrinsic spectral lineshapes in surface sum-frequency generation vibrational spectroscopy (SFG-VS) have limited its applications in surface and interfacial studies. The emergence of high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS) with sub-wavenumber resolution [Velarde et al., J. Chem. Phys., 2011, 135, 241102] offers new opportunities for obtaining and understanding the spectral lineshapes and temporal effects in SFG-VS. Particularly, the high accuracy of the HR-BB-SFG-VS experimental lineshape provides detailed information on the complex coherent vibrational dynamics through direct spectral measurements. Here we present a unified formalism for the theoretical and experimental routes for obtaining an accurate lineshape of the SFG response. Then, we present a detailed analysis of a cholesterol monolayer at the air/water interface with higher and lower resolution SFG spectra along with their temporal response. With higher spectral resolution and accurate vibrational spectral lineshapes, it is shown that the parameters of the experimental SFG spectra can be used both to understand and to quantitatively reproduce the temporal effects in lower resolution SFG measurements. This perspective provides not only a unified picture but also a novel experimental approach to measuring and understanding the frequency-domain and time-domain SFG response of a complex molecular interface.
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Affiliation(s)
- Luis Velarde
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, USA.
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27
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Sil S, Kuhar N, Acharya S, Umapathy S. Is chemically synthesized graphene 'really' a unique substrate for SERS and fluorescence quenching? Sci Rep 2013; 3:3336. [PMID: 24275718 PMCID: PMC3840363 DOI: 10.1038/srep03336] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 11/08/2013] [Indexed: 11/29/2022] Open
Abstract
We demonstrate observation of Raman signals of different analytes adsorbed on carbonaceous materials, such as, chemically reduced graphene, graphene oxide (GO), multi-walled carbon nanotube (MWCNT), graphite and activated carbon. The analytes selected for the study were Rhodamine 6G (R6G) (in resonant conditions), Rhodamine B (RB), Nile blue (NBA), Crystal Violet (CV) and acetaminophen (paracetamol). All the analytes except paracetamol absorb and fluoresce in the visible region. In this article we provide experimental evidence of the fact that observation of Raman signals of analytes on such carbonaceous materials are more due to resonance effect, suppression of fluorescence and efficient adsorption and that this property in not unique to graphene or nanotubes but prevalent for various type of carbon materials.
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Affiliation(s)
- Sanchita Sil
- 1] Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore, India [2] High Energy Materials research Laboratory, Sutarwadi, Pune, India
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28
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Rhinehart JM, Challa JR, McCamant DW. Multimode Charge-Transfer Dynamics of 4-(Dimethylamino)benzonitrile Probed with Ultraviolet Femtosecond Stimulated Raman Spectroscopy. J Phys Chem B 2012; 116:10522-34. [DOI: 10.1021/jp3020645] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Justin M. Rhinehart
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - J. Reddy Challa
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - David W. McCamant
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
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29
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30
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Qiu X, Li X, Niu K, Lee SY. Inverse Raman bands in ultrafast Raman loss spectroscopy. J Chem Phys 2011; 135:164502. [DOI: 10.1063/1.3653940] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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31
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Sahoo SK, Umapathy S, Parker AW. Time-resolved resonance Raman spectroscopy: exploring reactive intermediates. APPLIED SPECTROSCOPY 2011; 65:1087-115. [PMID: 21986070 DOI: 10.1366/11-06406] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The study of reaction mechanisms involves systematic investigations of the correlation between structure, reactivity, and time. The challenge is to be able to observe the chemical changes undergone by reactants as they change into products via one or several intermediates such as electronic excited states (singlet and triplet), radicals, radical ions, carbocations, carbanions, carbenes, nitrenes, nitrinium ions, etc. The vast array of intermediates and timescales means there is no single "do-it-all" technique. The simultaneous advances in contemporary time-resolved Raman spectroscopic techniques and computational methods have done much towards visualizing molecular fingerprint snapshots of the reactive intermediates in the microsecond to femtosecond time domain. Raman spectroscopy and its sensitive counterpart resonance Raman spectroscopy have been well proven as means for determining molecular structure, chemical bonding, reactivity, and dynamics of short-lived intermediates in solution phase and are advantageous in comparison to commonly used time-resolved absorption and emission spectroscopy. Today time-resolved Raman spectroscopy is a mature technique; its development owes much to the advent of pulsed tunable lasers, highly efficient spectrometers, and high speed, highly sensitive multichannel detectors able to collect a complete spectrum. This review article will provide a brief chronological development of the experimental setup and demonstrate how experimentalists have conquered numerous challenges to obtain background-free (removing fluorescence), intense, and highly spectrally resolved Raman spectra in the nanosecond to microsecond (ns-μs) and picosecond (ps) time domains and, perhaps surprisingly, laid the foundations for new techniques such as spatially offset Raman spectroscopy.
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Affiliation(s)
- Sangram Keshari Sahoo
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India
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32
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Kloz M, Grondelle RV, Kennis JT. Wavelength-modulated femtosecond stimulated raman spectroscopy—approach towards automatic data processing. Phys Chem Chem Phys 2011; 13:18123-33. [DOI: 10.1039/c1cp21650c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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