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Wait EE, Masunov AE, Vasu SS. Quantum chemical and master equation study of OH + CH
2
O → H
2
O + CHO reaction rates in supercritical CO
2
environment. INT J CHEM KINET 2018. [DOI: 10.1002/kin.21228] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Elizabeth E. Wait
- NanoScienece Technology Center University of Central Florida Orlando Florida
- Department of Chemistry University of Central Florida Orlando Florida
| | - Artëm E. Masunov
- NanoScienece Technology Center University of Central Florida Orlando Florida
- Department of Chemistry University of Central Florida Orlando Florida
- School of Modeling, Simulation, and Training University of Central Florida Orlando Florida
- South Ural State University Chelyabinsk Russia
- National Research Nuclear University MEPhI Moscow Russia
| | - Subith S. Vasu
- Center for Advanced Turbomachinery and Energy Research (CATER) Mechanical and Aerospace Engineering University of Central Florida Orlando Florida
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2
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Masunov AE, Wait E, Vasu SS. Quantum Chemical Study of CH 3 + O 2 Combustion Reaction System: Catalytic Effects of Additional CO 2 Molecule. J Phys Chem A 2017; 121:5681-5689. [PMID: 28722407 DOI: 10.1021/acs.jpca.7b04897] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The supercritical carbon dioxide diluent is used to control the temperature and to increase the efficiency in oxycombustion fossil fuel energy technology. It may affect the rates of combustion by altering mechanisms of chemical reactions, compared to the ones at low CO2 concentrations. Here, we investigate potential energy surfaces of the four elementary reactions in the CH3 + O2 reactive system in the presence of one CO2 molecule. In the case of reaction CH3 + O2 → CH2O + OH (R1 channel), van der Waals (vdW) complex formation stabilizes the transition state and reduces the activation barrier by ∼2.2 kcal/mol. Alternatively, covalently bonded CO2 may form a six-membered ring transition state and reduce the activation barrier by ∼0.6 kcal/mol. In case of reaction CH3 + O2 → CH3O + O (R2 channel), covalent participation of CO2 lowers the barrier for the rate limiting step by 3.9 kcal/mol. This is expected to accelerate the R2 process, important for the branching step of the radical chain reaction mechanism. For the reaction CH3 + O2 → CHO + H2O (R3 channel) with covalent participation of CO2, the activation barrier is lowered by 0.5 kcal/mol. The reaction CH2O + OH → CHO + H2O (R4 channel) involves hydrogen abstraction from formaldehyde by OH radical. Its barrier is reduced from 7.1 to 0.8 kcal/mol by formation of vdW complex with spectator CO2. These new findings are expected to improve the kinetic reaction mechanism describing combustion processes in supercritical CO2 medium.
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Affiliation(s)
- Artëm E Masunov
- South Ural State University , Lenin pr. 76, Chelyabinsk 454080, Russia.,National Research Nuclear University MEPhI , Kashirskoye shosse 31, Moscow 115409, Russia
| | | | - Subith S Vasu
- Center for Advanced Turbomachinery and Energy Research (CATER), Mechanical and Aerospace Engineering, University of Central Florida , Orlando, Florida 32816, United States
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Masunov AE, Wait EE, Atlanov AA, Vasu SS. Quantum Chemical Study of Supercritical Carbon Dioxide Effects on Combustion Kinetics. J Phys Chem A 2017; 121:3728-3735. [PMID: 28471684 DOI: 10.1021/acs.jpca.7b02638] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In oxy-fuel combustion, the pure oxygen (O2), diluted with CO2 is used as oxidant instead air. Hence, the combustion products (CO2 and H2O) are free from pollution by nitrogen oxides. Moreover, high pressures result in the near-liquid density of CO2 at supercritical state (sCO2). Unfortunately, the effects of sCO2 on the combustion kinetics are far from being understood. To assist in this understanding, in this work we are using quantum chemistry methods. Here we investigate potential energy surfaces of important combustion reactions in the presence of the carbon dioxide molecule. All transition states and reactant and product complexes are reported for three reactions: H2CO + HO2 → HCO + H2O2 (R1), 2HO2 → H2O2 + O2 (R2), and CO + OH → CO2 + H (R3). In reaction R3, covalent binding of CO2 to the OH radical and then the CO molecule opens a new pathway, including hydrogen transfer from oxygen to carbon atoms followed by CH bond dissociation. Compared to the bimolecular OH + CO mechanism, this pathway reduces the activation barrier by 5 kcal/mol and is expected to accelerate the reaction. In the case of hydroperoxyl self-reaction 2HO2 → H2O2 + O2 the intermediates, containing covalent bonds to CO2 are found not to be competitive. However, the spectator CO2 molecule can stabilize the cyclic transition state and lower the barrier by 3 kcal/mol. Formation of covalent intermediates is also discovered in the H2CO + HO2 → HCO + H2O2 reaction, but these species lead to substantially higher activation barriers, which makes them unlikely to play a role in hydrogen transfer kinetics. The van der Waals complexation with carbon dioxide also stabilizes the transition state and reduces the reaction barrier. These results indicate that the CO2 environment is likely to have a catalytic effect on combustion reactions, which needs to be included in kinetic combustion mechanisms in supercritical CO2.
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Affiliation(s)
- Artëm E Masunov
- National Research Nuclear University MEPhI , Kashirskoye shosse 31, Moscow 115409, Russia.,South Ural State University , Lenin pr. 76, Chelyabinsk 454080, Russia
| | | | - Arseniy A Atlanov
- Department of Chemistry and Biochemistry, 95 Chieftan Way Room 118 DLC, Florida State University , Tallahassee, Florida 32806, United States
| | - Subith S Vasu
- Center for Advanced Turbomachinery and Energy Research (CATER), Mechanical and Aerospace Engineering, University of Central Florida , Orlando, Florida 32816, United States
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Masunov AE, Atlanov AA, Vasu SS. Potential Energy Surfaces for the Reactions of HO 2 Radical with CH 2O and HO 2 in CO 2 Environment. J Phys Chem A 2016; 120:7681-7688. [PMID: 27552660 DOI: 10.1021/acs.jpca.6b07257] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report on potential energies for the transition state, reactant, and product complexes along the reaction pathways for hydrogen transfer reactions to hydroperoxyl radical from formaldehyde H2CO + HO2 → HCO + H2O2 and another hydroperoxyl radical 2HO2 → H2O2 + O2 in the presence of one carbon dioxide molecule. Both covalently bonded intermediates and weak intermolecular complexes are identified and characterized. We found that reactions that involve covalent intermediates have substantially higher activation barriers and are not likely to play a role in hydrogen transfer kinetics. The van der Waals complexation with carbon dioxide does not affect hydrogen transfer from formaldehyde, but it lowers the barrier for hydroperoxyl self-reaction by nearly 3 kcal/mol. This indicates that CO2 environment is likely to have catalytic effect on HO2 self-reaction, which needs to be included in kinetic combustion mechanisms in supercritical CO2.
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Affiliation(s)
- Artëm E Masunov
- National Research Nuclear University MEPhI , Kashirskoye shosse 31, Moscow 115409, Russia
| | - Arseniy A Atlanov
- Department of Chemistry and Biochemistry, 95 Chieftan Way Rm. 118 DLC, Florida State University , Tallahassee, Florida 32806, United States
| | - Subith S Vasu
- Center for Advanced Turbomachinery and Energy Research (CATER), Mechanical and Aerospace Engineering, University of Central Florida , Orlando, Florida 32816, United States
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Bohnwagner MV, Burghardt I, Dreuw A. Solvent Polarity Tunes the Barrier Height for Twisted Intramolecular Charge Transfer in N-Pyrrolobenzonitrile (PBN). J Phys Chem A 2015; 120:14-27. [DOI: 10.1021/acs.jpca.5b09115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mercedes V. Bohnwagner
- Interdisciplinary
Center for Scientific Computing, Ruprecht-Karls University, Im Neuenheimer
Feld 368, 69120 Heidelberg, Germany
- Institute
of Physical and Theoretical Chemistry, Goethe-University, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Irene Burghardt
- Institute
of Physical and Theoretical Chemistry, Goethe-University, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Andreas Dreuw
- Interdisciplinary
Center for Scientific Computing, Ruprecht-Karls University, Im Neuenheimer
Feld 368, 69120 Heidelberg, Germany
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Barlow S, Risko C, Odom SA, Zheng S, Coropceanu V, Beverina L, Brédas JL, Marder SR. Tuning Delocalization in the Radical Cations of 1,4-Bis[4-(diarylamino)styryl]benzenes, 2,5-Bis[4-(diarylamino)styryl]thiophenes, and 2,5-Bis[4-(diarylamino)styryl]pyrroles through Substituent Effects. J Am Chem Soc 2012; 134:10146-55. [DOI: 10.1021/ja3023048] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen Barlow
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Chad Risko
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Susan A. Odom
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Shijun Zheng
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Veaceslav Coropceanu
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Luca Beverina
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Jean-Luc Brédas
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Seth R. Marder
- Center for
Organic Photonics and Electronics and School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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7
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Silverstein DW, Jensen L. Vibronic coupling simulations for linear and nonlinear optical processes: Theory. J Chem Phys 2012; 136:064111. [DOI: 10.1063/1.3684236] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Cai Z, Zhou M, Xu J. Degenerate four-wave mixing determination of third-order optical nonlinearities of three mixed ligand nickel(II) complexes. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Badaeva E, Harpham MR, Guda R, Süzer Ö, Ma CQ, Bäuerle P, Goodson T, Tretiak S. Excited-State Structure of Oligothiophene Dendrimers: Computational and Experimental Study. J Phys Chem B 2010; 114:15808-17. [DOI: 10.1021/jp109624d] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ekaterina Badaeva
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Michael R. Harpham
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ramakrishna Guda
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Özgün Süzer
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Chang-Qi Ma
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Peter Bäuerle
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Theodore Goodson
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States, Department of Chemistry, Applied Physics Program, The University of Michigan, Ann Arbor Michigan 48109, United States, Institute of Organic Chemistry II and Advanced Materials, University of Ulm, 89081, Ulm, Germany, and Theoretical Division, Center for Nonlinear Studies (CNLS), and Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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Katan C, Blanchard-Desce M, Tretiak S. Position Isomerism on One and Two Photon Absorption in Multibranched Chromophores: A TDDFT Investigation. J Chem Theory Comput 2010; 6:3410-26. [DOI: 10.1021/ct1004406] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Claudine Katan
- Université Européenne de Bretagne, CNRS—Chimie et Photonique Moléculaires (CPM), Université de Rennes 1, 35042 Rennes, France, and Université Européenne de Bretagne, CNRS—Fonctions Optiques pour les Technologies de l’Information (FOTON), INSA de Rennes, CS70839, 35708 Rennes, France, and Center for NonLinear Studies (CNLS) and Center for Integrated NanoTechnologies (CINT), Los Alamos, New Mexico 87545, United States
| | - Mireille Blanchard-Desce
- Université Européenne de Bretagne, CNRS—Chimie et Photonique Moléculaires (CPM), Université de Rennes 1, 35042 Rennes, France, and Université Européenne de Bretagne, CNRS—Fonctions Optiques pour les Technologies de l’Information (FOTON), INSA de Rennes, CS70839, 35708 Rennes, France, and Center for NonLinear Studies (CNLS) and Center for Integrated NanoTechnologies (CINT), Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Université Européenne de Bretagne, CNRS—Chimie et Photonique Moléculaires (CPM), Université de Rennes 1, 35042 Rennes, France, and Université Européenne de Bretagne, CNRS—Fonctions Optiques pour les Technologies de l’Information (FOTON), INSA de Rennes, CS70839, 35708 Rennes, France, and Center for NonLinear Studies (CNLS) and Center for Integrated NanoTechnologies (CINT), Los Alamos, New Mexico 87545, United States
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Masunov AE, Mikhailov IA. Theory and computations of two-photon absorbing photochromic chromophores. ACTA ACUST UNITED AC 2010. [DOI: 10.5155/eurjchem.1.2.142-161.119] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Singlet exciton fission for solar cell applications: energy aspects of interchromophore coupling. J Phys Chem B 2009; 114:14223-32. [PMID: 20025238 DOI: 10.1021/jp909002d] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Singlet exciton fission, a process that converts one singlet exciton to a pair of triplet excitons, has the potential to enhance the efficiency of both bulk heterojunction and dye-sensitized solar cells and is understood in crystals but not well understood in molecules. Previous studies have identified promising building blocks for singlet fission in molecular systems, but little work has investigated how these individual chromophores should be combined to maximize triplet yield. We consider the effects of chemically connecting two chromophores to create a coupled chromophore pair and compute how various structural choices alter the thermodynamic and kinetic parameters likely to control singlet fission yield. We use density functional theory to compute the electron transfer matrix element and the thermodynamics of fission for several promising chromophore pairs and find a trade-off between the desire to maximize this element and the desire to keep the singlet fission process exoergic. We identify promising molecular systems for singlet fission and suggest future experiments.
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Elliott P, Furche F, Burke K. Excited States from Time-Dependent Density Functional Theory. REVIEWS IN COMPUTATIONAL CHEMISTRY 2009. [DOI: 10.1002/9780470399545.ch3] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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14
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Ye JF, Chen H, Note R, Mizuseki H, Kawazoe Y. Excess polarizabilities upon the first dipole-allowed excitation of some conjugated oligomers. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Berlin A, Risko C, Ratner MA. Geometric and Chelation Influences on the Electronic Structure and Optical Properties of Tetra(carboxylic acid)phenyleneethynylene Dyes. J Phys Chem A 2008; 112:4202-8. [DOI: 10.1021/jp077692z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Asher Berlin
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Chad Risko
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Mark A. Ratner
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
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De Boni L, Toro C, Masunov AE, Hernández FE. Untangling the Excited States of DR1 in Solution: An Experimental and Theoretical Study. J Phys Chem A 2008; 112:3886-90. [DOI: 10.1021/jp711552e] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Leonardo De Boni
- Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 382616-2366
| | - Carlos Toro
- Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 382616-2366
| | - Artëm E. Masunov
- Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 382616-2366
| | - Florencio E. Hernández
- Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 382616-2366
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Katan C, Tretiak S, Werts MHV, Bain AJ, Marsh RJ, Leonczek N, Nicolaou N, Badaeva E, Mongin O, Blanchard-Desce M. Two-photon transitions in quadrupolar and branched chromophores: experiment and theory. J Phys Chem B 2007; 111:9468-83. [PMID: 17658741 DOI: 10.1021/jp071069x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combined experimental and theoretical study is conducted on a series of model compounds in order to assess the combined role of branching and charge symmetry on absorption, photoluminescence, and two-photon absorption (TPA) properties. The main issue of this study is to examine how branching of quadrupolar chomophores can lead to different consequences as compared to branching of dipolar chromophores. Hence, three structurally related pi-conjugated quadrupolar chromophores symmetrically substituted with donor end groups and one branched structure built from the assembly of three quadrupolar branches via a common donor moiety are used as model compounds. Their photophysical properties are studied using UV-vis spectroscopy, and the TPA spectra are determined through two-photon excited fluorescence experiments using femtosecond pulses in the 500-1000 nm range. Experimental studies are complemented by theoretical calculations. The applied theoretical methodology is based on time-dependent density functional theory, the Frenkel exciton model, and analysis in terms of the natural transition orbitals of relevant electronic states. Theory reveals that a symmetrical intramolecular charge transfer from the terminal donating groups to the middle of the molecule takes place in all quadrupolar chromophores upon photoexcitation. In contrast, branching via a central electron-donating triphenylamine moiety breaks the quadrupolar symmetry of the branches. Consequently, all Frank-Condon excited states have significant asymmetric multidimensional charge-transfer character upon excitation. Subsequent vibrational relaxation of the branched chromophore in the excited state leads to a localization of the excitation and fluorescence stemming from a single branch. As opposed to what was earlier observed when dipolar chromophores are branched via the same common electron-donating moiety, we find only a slight enhancement of the maximum TPA response of the branched compound with respect to an additive contribution of its quadrupolar branches. In contrast, substantial modifications of the spectral shape are observed. This is attributed to the subtle interplay of interbranch electronic coupling and asymmetry caused by branching.
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Affiliation(s)
- Claudine Katan
- Synthèse et ElectroSynthèse Organiques (CNRS, UMR 6510), Université de Rennes 1, Campus de Beaulieu, Bât 10A Case 1003, F-35042 Rennes Cedex, France.
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Badaeva EA, Timofeeva TV, Masunov A, Tretiak S. Role of donor-acceptor strengths and separation on the two-photon absorption response of cytotoxic dyes: a TD-DFT study. J Phys Chem A 2007; 109:7276-84. [PMID: 16834093 DOI: 10.1021/jp0521510] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-dependent density functional theory (TD-DFT) is applied to model one-photon (OPA) and two-photon (TPA) absorption spectra in a series of conjugated cytotoxic dyes. Good agreement with available experimental data is found for calculated excitation energies and cross sections. Calculations show that both OPA and TPA spectra in the molecules studied are typically dominated by two strong peaks corresponding to different electronic states. We find that donor-acceptor strengths and conjugated bridge length have a strong impact on the cross-section magnitudes of low- and high-frequency TPA maxima, respectively. These trends are analyzed in terms of the natural transition orbitals of the corresponding electronic states. Observed structure-property relationships may have useful implications on design of organic conjugated chromophores with tunable two-photon absorption properties for photodynamic therapy applications.
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Affiliation(s)
- Ekaterina A Badaeva
- Department of Natural Sciences, Highlands University, Las Vegas, New Mexico 87701, USA
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Burke K, Werschnik J, Gross EKU. Time-dependent density functional theory: past, present, and future. J Chem Phys 2007; 123:62206. [PMID: 16122292 DOI: 10.1063/1.1904586] [Citation(s) in RCA: 505] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Time-dependent density functional theory (TDDFT) is presently enjoying enormous popularity in quantum chemistry, as a useful tool for extracting electronic excited state energies. This article discusses how TDDFT is much broader in scope, and yields predictions for many more properties. We discuss some of the challenges involved in making accurate predictions for these properties.
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Affiliation(s)
- Kieron Burke
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
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Zhang Y, Zhao J, Tang G, Zhu L. Theoretical studies on vibrational spectra of some halides of group IVB elements. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 64:420-5. [PMID: 16384738 DOI: 10.1016/j.saa.2005.07.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 07/08/2005] [Accepted: 07/17/2005] [Indexed: 05/05/2023]
Abstract
The vibrational spectra of group IVB elements halides MX4 (M=Ti(IV), Zr(IV), Hf(II); X=F, Cl, Br and I), have been investigated by ab initio RHF, MP2 and density functional theory B3LYP method with LanL2DZ basis sets. The optimized geometries, calculated vibrational frequencies and Far-IR intensities of MX4 are evaluated via comparison with experimental data. The vibrational frequencies, calculated by these methods, are compared to each other. The results indicate that B3LYP method is more reliable than RHF and MP2 methods for the frequencies calculations for these compounds. With this method, some vibrational frequencies of M2X6(2+)(M=Ti(IV), Zr(IV) and Hf(II); X=F, Cl, Br and I) are also predicted.
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Affiliation(s)
- Yu Zhang
- Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, Department of Chemistry, Huaiyin Teachers College, Huai'an 223001, Jiangsu, PR China.
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Kauffman JF, Turner JM, Alabugin IV, Breiner B, Kovalenko SV, Badaeva EA, Masunov A, Tretiak S. Two-Photon Excitation of Substituted Enediynes. J Phys Chem A 2005; 110:241-51. [PMID: 16392861 DOI: 10.1021/jp056127y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electronic spectroscopy of nine benzannelated enediynes and a related fulvene was studied under one-photon and two-photon excitation conditions. We utilize measured absorbance and emission spectra and time-resolved fluorescence decays of these molecules to calculate their radiative lifetimes and fluorescence quantum yields. The fluorescence quantum yields for the other compounds were referenced to the fluorescence quantum yield of compound 3 and used to determine relative two-photon absorption cross-sections. Further insight into experimental studies has been achieved using time-dependent density functional (TD-DFT) computations. The probability of two-photon absorption (TPA) increases noticeably for excitation to the higher excited states. The photophysical properties of benzannelated enediynes are sensitive to substitutions at both the core and the periphery of the enediyne chromophore. Considerably enhanced two-photon absorption is observed in an enediyne with donor substitution in the middle and acceptor substitution at the termini. Excited states with B symmetry are not active in TPA spectra. From a practical point of view, this study extends the range of wavelengths applicable for activation of the enediyne moiety from 350 to 600 nm and provides a rational basis for future studies in this field. Our theoretical computations confirmed that lowest energy TPA in benzannelated enediynes involves different orbitals than lowest energy one-photon absorbance and provided further support to the notion that introduction of donor and acceptor substituents at different ends of a molecule increases TPA.
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Affiliation(s)
- John F Kauffman
- Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
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Masunov A, Tretiak S, Hong JW, Liu B, Bazan GC. Theoretical study of the effects of solvent environment on photophysical properties and electronic structure of paracyclophane chromophores. J Chem Phys 2005; 122:224505. [PMID: 15974689 DOI: 10.1063/1.1878732] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use first-principles quantum-chemical approaches to study absorption and emission properties of recently synthesized distyrylbenzene (DSB) derivative chromophores and their dimers (two DSB molecules linked through a [2.2]paracyclophane moiety). Several solvent models are applied to model experimentally observed shifts and radiative lifetimes in Stokes nonpolar organic solvents (toluene) and water. The molecular environment is simulated using the implicit solvation models, as well as explicit water molecules and counterions. Calculations show that neither implicit nor explicit solvent models are sufficient to reproduce experimental observations. The contact pair between the chromophore and counterion, on the other hand, is able to reproduce the experimental data when a partial screening effect of the solvent is taken into account. Based on our simulations we suggest two mechanisms for the excited-state lifetime increase in aqueous solutions. These findings may have a number of implications for organic light-emitting devices, electronic functionalities of soluble polymers and molecular fluorescent labels, and their possible applications as biosensors and charge/energy conduits in nanoassemblies.
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Affiliation(s)
- Artëm Masunov
- Los Alamos National Laboratory, Theoretical Division and Center for Nonlinear Studies, Los Alamos, New Mexico 87545, USA.
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Katan C, Terenziani F, Mongin O, Werts MHV, Porrès L, Pons T, Mertz J, Tretiak S, Blanchard-Desce M. Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption. J Phys Chem A 2005; 109:3024-37. [PMID: 16833626 DOI: 10.1021/jp044193e] [Citation(s) in RCA: 315] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To investigate the effect of branching on linear and nonlinear optical properties, a specific series of chromophores, epitome of (multi)branched dipoles, has been thoroughly explored by a combined theoretical and experimental approach. Excited-state structure calculations based on quantum-chemical techniques (time-dependent density functional theory) as well as a Frenkel exciton model nicely complement experimental photoluminescence and one- and two-photon absorption findings and contribute to their interpretation. This allowed us to get a deep insight into the nature of fundamental excited-state dynamics and the nonlinear optical (NLO) response involved. Both experiment and theory reveal that a multidimensional intramolecular charge transfer takes place from the donating moiety to the periphery of the branched molecules upon excitation, while fluorescence stems from an excited state localized on one of the dipolar branches. Branching is also observed to lead to cooperative enhancement of two-photon absorption (TPA) while maintaining high fluorescence quantum yield, thanks to localization of the emitting state. The comparison between results obtained in the Frenkel exciton scheme and ab initio results suggests the coherent coupling between branches as one of the possible mechanisms for the observed enhancement. New strategies for the rational design of NLO molecular assemblies are thus inferred on the basis of the acquired insights.
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Affiliation(s)
- Claudine Katan
- Synthèse et ElectroSynthèse Organiques (CNRS, UMR 6510), Université de Rennes 1, Institut de Chimie, Campus Scientifique de Beaulieu, Bât 10A, F-35042 Rennes Cedex, France
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