1
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Giussani A, Segarra-Martí J. XMS-CASPT2//XMS-CASPT2 and XMS-CASPT2//CASSCF at comparison: The impact of dynamic correlation in the excited state optimization of nitronaphthalene. J Chem Phys 2024; 161:011103. [PMID: 38953440 DOI: 10.1063/5.0203550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/12/2024] [Indexed: 07/04/2024] Open
Abstract
Here, analytical extended multi-state complete active space second-order perturbation method (XMS-CASPT2) gradients are used to rationalize the decreasing triplet quantum yield trend in 2-nitronaphthalene, 1-nitronaphthalene, and 2-methyl-1-nitronaphthalene, a series of nitro-substituted aromatic compounds. Comparison with the XMS-CASPT2//CASSCF (where CASSCF stands for complete active space self-consistent field method) results highlights the importance of dynamic correlation in geometry optimization and challenges the validity of an XMS-CASPT2//CASSCF approach: XMS-CASPT2 S1 minima leads to planar structures, while CASSCF optimizations trigger a pyramidalization of the nitro group. The XMS-CASPT2 results correlate the reported decreasing triplet quantum yield trend in these species to a decrease in S1 to T2 population transfer and an increase in S1-S0 decay, while no such correlation is observed when using XMS-CASPT2//CASSCF data.
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Affiliation(s)
- Angelo Giussani
- Instituto de Ciencia Molecular, Universitat de València, Apartado22085, ES-46071 Valencia, Spain
| | - Javier Segarra-Martí
- Instituto de Ciencia Molecular, Universitat de València, Apartado22085, ES-46071 Valencia, Spain
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2
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Giussani A, Worth GA. A First Proposal on the Nitrobenzene Photorelease Mechanism of NO 2 and Its Relation to NO Formation through a Roaming Mechanism. J Phys Chem Lett 2024; 15:2216-2221. [PMID: 38373198 PMCID: PMC10910573 DOI: 10.1021/acs.jpclett.3c03457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
Despite the fact that NO2 is considered to be the main photoproduct of nitrobenzene photochemistry, no mechanism has ever been proposed to rationalize its formation. NO photorelease is instead a more studied process, probably due to its application in the drug delivery sector and the study of roaming mechanisms. In this contribution, a photoinduced mechanism accounting for the formation of NO2 in nitrobenzene is theorized based on CASPT2, CASSCF, and DFT electronic structure calculations and CASSCF classical dynamics. A triplet nπ* state is shown to evolve toward C-NO2 dissociation, being, in fact, the only low-lying excited state favoring such a deformation. Along the triplet dissociation path, the possibility to decay to the singlet ground state results in the frustration of the dissociation and in the recombination of the fragments, either back to the nitro or the nitrite isomer. The thermal decomposition of the latter to NO constitutes globally a roaming mechanism of NO formation.
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Affiliation(s)
- Angelo Giussani
- Instituto
de Ciencia Molecular, Universitat de València, Apartado 22085, ES-46071 Valencia, Spain
| | - Graham A. Worth
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
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3
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Wang PY, Hsu YC, Chen PH, Chen GY, Liao YK, Cheng PY. Solvent-polarity dependence of ultrafast excited-state dynamics of trans-4-nitrostilbene. Phys Chem Chem Phys 2024; 26:788-807. [PMID: 38088777 DOI: 10.1039/d3cp05245a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Ultrafast excited-state dynamics of the simplest nitrostilbenes, namely trans-4-nitrostilbene (t-NSB), was studied in solvents of various polarities with ultrafast broadband time-resolved fluorescence and transient absorption spectroscopies, and by quantum-chemical computations. The results revealed that the initially excited S1(ππ*) state deactivation dynamics is strongly influenced by the solvent polarity. Specifically, the t-NSB S1-state lifetime decreases by three orders of magnitude from ∼60 ps in high-polarity solvents to ∼60 fs in nonpolar solvents. The strong solvent-polarity dependence arises from the differences in dipole moments among the S1 and relevant states, including the major intersystem crossing (ISC) receiver triplet states, and therefore, the solvent polarity can modulate their relative energies and ISC rates. In nonpolar solvents, the sub-100 fs lifetime is due to a combination of efficient ISC and internal conversion. In medium-polarity solvents, the S1-state population decays via a competing ISC relaxation mechanism in a biphasic manner, and the ISC rates are found to obey the inverse energy gap law of the strong coupling case. In high-polarity solvents, the S1 state is stabilized to a much lower energy such that ISC becomes energetically infeasible, and the S1 state decays via barrier crossing along the torsion angle of the central ethylenic bond to the nonfluorescent perpendicular configuration. Regardless of the initial S1-state deactivation pathways in various solvents, the excited-state population is ultimately trapped in the metastable T1-state perpendicular configuration, at which a slower ISC occurs to bring the system to the ground state and bifurcate into either trans or cis form of NSB.
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Affiliation(s)
- Peng-Yun Wang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, 30043, Republic of China.
| | - Yu-Cheng Hsu
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, 30043, Republic of China.
| | - Pin-Hsun Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, 30043, Republic of China.
| | - Guan-Yu Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, 30043, Republic of China.
| | - Yi-Kai Liao
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, 30043, Republic of China.
| | - Po-Yuan Cheng
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, 30043, Republic of China.
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4
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Fu Y, Yan Y, Wei Z, Spinney R, Dionysiou DD, Vione D, Liu M, Xiao R. Overlooked Transformation of Nitrated Polycyclic Aromatic Hydrocarbons in Natural Waters: Role of Self-Photosensitization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37327199 DOI: 10.1021/acs.est.3c02276] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Photochemical transformation is an important process that involves trace organic contaminants (TrOCs) in sunlit surface waters. However, the environmental implications of their self-photosensitization pathway have been largely overlooked. Here, we selected 1-nitronaphthalene (1NN), a representative nitrated polycyclic aromatic hydrocarbon, to study the self-photosensitization process. We investigated the excited-state properties and relaxation kinetics of 1NN after sunlight absorption. The intrinsic decay rate constants of triplet (31NN*) and singlet (11NN*) excited states were estimated to be 1.5 × 106 and 2.5 × 108 s-1, respectively. Our results provided quantitative evidence for the environmental relevance of 31NN* in waters. Possible reactions of 31NN* with various water components were evaluated. With the reduction and oxidation potentials of -0.37 and 1.95 V, 31NN* can be either oxidized or reduced by dissolved organic matter isolates and surrogates. We also showed that hydroxyl (•OH) and sulfate (SO4•-) radicals can be generated via the 31NN*-induced oxidation of inorganic ions (OH- and SO42-, respectively). We further investigated the reaction kinetics of 31NN* and OH- forming •OH, an important photoinduced reactive intermediate, through complementary experimental and theoretical approaches. The rate constants for the reactions of 31NN* with OH- and 1NN with •OH were determined to be 4.22 × 107 and 3.95 ± 0.01 × 109 M-1 s-1, respectively. These findings yield new insights into self-photosensitization as a pathway for TrOC attenuation and provide more mechanistic details into their environmental fate.
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Affiliation(s)
- Yifu Fu
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Yiqi Yan
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Zongsu Wei
- Centre for Water Technology (WATEC) & Department of Engineering, Aarhus University, Hangøvej 2, Aarhus N DK-8200, Denmark
| | - Richard Spinney
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Davide Vione
- Department of Chemistry, University of Turin, Via Pietro Giuria 5, Torino 10125, Italy
| | - Min Liu
- State Key Laboratory of Powder Metallurgy, School of Physics and Electronics, Central South University, Changsha 410083, China
| | - Ruiyang Xiao
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
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5
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Wu Y, Wang Y, Guan H, Du Y, Zheng X, Xue J. Effect of electron-donating substitution on the triplet state reactivities of 1-nitronaphthalene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:121997. [PMID: 36308824 DOI: 10.1016/j.saa.2022.121997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/23/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), often found in polluted air, are carcinogenic and mutagenic. The nitro group increases the spin-orbit coupling and results in the lowest excited triplet (T1) on the picosecond time scale with a high yield. The electron-donating substituents have a significant influence on the photophysics and photochemistry of nitro-PAHs. We used transient absorption spectroscopy and kinetic analysis to investigate the reactivities of the T1 state 1-methoxy-4-nitronaphthalene (3MeO-NN) and 1-methyl-4-nitronaphthalene (3Me-NN). The results show that the methoxy and methyl substitutions have a minor effect on their hydrogen abstraction and electron accepting abilities. The main distinction is their reaction rates towards protons. The second order rate constant of 3MeO-NN towards protons is three orders of magnitude greater than that of 3Me-NN, indicating that 3MeO-NN has a stronger hydrogen bond accepting ability. The kinetic analysis reveals that the dimer of 2,2,2-trifluoroethanol participates in the reaction with 3MeO-NN. These results suggest that the formation of the hydrogen-bonded complex is responsible for the unusually short lifetime of 3MeO-NN in methanol solution and the lack of hydrogen abstraction radicals during the decay of 3MeO-NN in methanol.
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Affiliation(s)
- Yu Wu
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yangxin Wang
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Huaiyu Guan
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yong Du
- Centre for THz Research, Jiliang University, Hangzhou 310018, China
| | - Xuming Zheng
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jiadan Xue
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China; Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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6
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Giussani A, Worth GA. On the photorelease of nitric oxide by nitrobenzene derivatives: A CASPT2//CASSCF model. J Chem Phys 2022; 157:204301. [PMID: 36456224 DOI: 10.1063/5.0125460] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Nitroaromatic compounds can photorelease nitric oxide after UV absorption. The efficiency of the photoreaction depends on the molecular structure, and two features have been pointed out as particularly important for the yield of the process: the presence of methyl groups at the ortho position with respect to the nitro group and the degree of conjugation of the molecule. In this paper, we provide a theoretical characterization at the CASPT2//CASSCF (complete active space second-order perturbation theory//complete active space self-consistent field) level of theory of the photorelease of NO for four molecules derived from nitrobenzene through the addition of ortho methyl groups and/or the elongation of the conjugation. Our previously described mechanism obtained for the photorelease of NO in nitrobenzene has been adopted as a model for the process. According to this model, the process proceeds through a reactive singlet-triplet crossing (STC) region that the system can reach from the triplet 3(πOπ*) minimum. The energy barrier that must be surmounted in order to populate the reactive STC can be associated with the efficiency of the photoreaction. Here, the obtained results display clear differences in the efficiency of the photoreaction in the studied systems and can be correlated with experimental results. Thus, the model proves its ability to highlight the differences in the photoreaction efficiency for the nitroaromatic compounds studied here.
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Affiliation(s)
- Angelo Giussani
- Instituto de Ciencia Molecular, Universitat de València, Apartado22085, ES-46071 Valencia, Spain
| | - Graham A Worth
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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7
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Sarkar R, Loos PF, Boggio-Pasqua M, Jacquemin D. Assessing the Performances of CASPT2 and NEVPT2 for Vertical Excitation Energies. J Chem Theory Comput 2022; 18:2418-2436. [PMID: 35333060 DOI: 10.1021/acs.jctc.1c01197] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Methods able to simultaneously account for both static and dynamic electron correlations have often been employed, not only to model photochemical events but also to provide reference values for vertical transition energies, hence allowing benchmarking of lower-order models. In this category, both the complete-active-space second-order perturbation theory (CASPT2) and the N-electron valence state second-order perturbation theory (NEVPT2) are certainly popular, the latter presenting the advantage of not requiring the application of the empirical ionization-potential-electron-affinity (IPEA) and level shifts. However, the actual accuracy of these multiconfigurational approaches is not settled yet. In this context, to assess the performances of these approaches, the present work relies on highly accurate (±0.03 eV) aug-cc-pVTZ vertical transition energies for 284 excited states of diverse character (174 singlet, 110 triplet, 206 valence, 78 Rydberg, 78 n → π*, 119 π → π*, and 9 double excitations) determined in 35 small- to medium-sized organic molecules containing from three to six non-hydrogen atoms. The CASPT2 calculations are performed with and without IPEA shift and compared to the partially contracted (PC) and strongly contracted (SC) variants of NEVPT2. We find that both CASPT2 with IPEA shift and PC-NEVPT2 provide fairly reliable vertical transition energy estimates, with slight overestimations and mean absolute errors of 0.11 and 0.13 eV, respectively. These values are found to be rather uniform for the various subgroups of transitions. The present work completes our previous benchmarks focused on single-reference wave function methods ( J. Chem. Theory Comput. 2018, 14, 4360; J. Chem. Theory Comput. 2020, 16, 1711), hence allowing for a fair comparison between various families of electronic structure methods. In particular, we show that ADC(2), CCSD, and CASPT2 deliver similar accuracies for excited states with a dominant single-excitation character.
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Affiliation(s)
| | - Pierre-François Loos
- Laboratoire de Chimie et Physique Quantiques, CNRS, UPS, Université de Toulouse, Toulouse 31062, France
| | - Martial Boggio-Pasqua
- Laboratoire de Chimie et Physique Quantiques, CNRS, UPS, Université de Toulouse, Toulouse 31062, France
| | - Denis Jacquemin
- Université de Nantes, CNRS, CEISAM UMR 6230, F-44000 Nantes, France
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8
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Mazumder A, Sebastian E, Hariharan M. Solvent dielectric delimited nitro–nitrito photorearrangement in a perylenediimide derivative. Chem Sci 2022; 13:8860-8870. [PMID: 35975155 PMCID: PMC9350666 DOI: 10.1039/d2sc02979k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/04/2022] [Indexed: 12/04/2022] Open
Abstract
The discovery of vibrant excited-state dynamics and distinctive photochemistry has established nitrated polycyclic aromatic hydrocarbons as an exhilarating class of organic compounds. Herein, we report the atypical photorearrangement of nitro-perylenediimide (NO2-PDI) to nitrito-perylenediimide (ONO-PDI), triggered by visible-light excitation and giving rise to linkage isomers in the polar aprotic solvent acetonitrile. ONO-PDI has been isolated and unambiguously characterized using standard spectroscopic, spectrometric, and elemental composition techniques. Although nitritoaromatic compounds are conventionally considered to be crucial intermediates in the photodissociation of nitroaromatics, experimental evidence for this has not been observed heretofore. Ultrafast transient absorption spectroscopy combined with computational investigations revealed the prominence of a conformationally relaxed singlet excited-state (SCR1) of NO2-PDI in the photoisomerization pathway. Theoretical transition state (TS) analysis indicated the presence of a six-membered cyclic TS, which is pivotal in connecting the SCR1 state to the photoproduct state. This article addresses prevailing knowledge gaps in the field of organic linkage isomers and provides a comprehensive understanding of the unprecedented photoisomerization mechanism operating in the case of NO2-PDI. The unprecedented photorearrangement of nitro-perylenediimide (NO2-PDI) to nitrito-perylenediimide (ONO-PDI) is shown to occur through a cyclic six-membered transition state triggered by visible-light excitation.![]()
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Affiliation(s)
- Aniruddha Mazumder
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala, India 695551
| | - Ebin Sebastian
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala, India 695551
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala, India 695551
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9
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Rodríguez-Córdoba W, Gutiérrez-Arzaluz L, Cortés-Guzmán F, Peon J. Excited state dynamics and photochemistry of nitroaromatic compounds. Chem Commun (Camb) 2021; 57:12218-12235. [PMID: 34735557 DOI: 10.1039/d1cc04999b] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nitrated aromatic molecules have unique photoinduced channels. Due to the presence of oxygen-centered non-bonding orbitals, they can undergo sub-picosecond intersystem crossing showing one of the strongest couplings between the singlet and triplet manifolds among organic molecules. Several nitroaromatic compounds also have a distinctive nitric oxide photodissociation channel which occurs through a complex sequence of atom rearrangements and state changes. These remarkable processes have stimulated the attention of several research groups over the last few years who have applied modern femtosecond spectroscopies and new computational methods to these topics. Nitroaromatic molecules also have demonstrated their value as case-studies, where they can serve to understand the influence of torsional motions between the nitro substituent and the aromatic system in the conversions between states. In this contribution we highlight several of the recent results in this area. Due to the importance of the atmospheric photochemistry of nitrated compounds and their accumulating applications as nitric oxide release agents, continued research about the effects of the different state orderings, substitution patterns, and solvent effects is central to the development of future applications and for a better understanding of their environmental pathways. From this analysis, several pending issues are highlighted, which include the nature of the dominant singlet state involved in intersystem crossing, the role of the formation of charge-transfer states, the yield of the internal conversion channel to the electronic ground state, and a more generalized understanding of the sequence of steps which lead to nitric oxide dissociation.
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Affiliation(s)
- William Rodríguez-Córdoba
- Facultad de ciencias, Escuela de Física, Laboratorio de Fotónica y Optoelectrónica, Universidad Nacional de Colombia - Sede Medellín, Calle 59 A No. 63-20, A.A. 3840, Medellín, Colombia.
| | - Luis Gutiérrez-Arzaluz
- Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
| | - Fernando Cortés-Guzmán
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 D.F., Mexico.
| | - Jorge Peon
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 D.F., Mexico.
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10
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Wilson J, Octaviani M, Bandowe BAM, Wietzoreck M, Zetzsch C, Pöschl U, Berkemeier T, Lammel G. Modeling the Formation, Degradation, and Spatiotemporal Distribution of 2-Nitrofluoranthene and 2-Nitropyrene in the Global Atmosphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14224-14234. [PMID: 33112146 PMCID: PMC7676291 DOI: 10.1021/acs.est.0c04319] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/07/2020] [Accepted: 10/16/2020] [Indexed: 05/19/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are common atmospheric pollutants and known to cause adverse health effects. Nitrated PAHs (NPAHs) are formed in combustion activities and by nitration of PAHs in the atmosphere and may be equally or more toxic, but their spatial and temporal distribution in the atmosphere is not well characterized. Using the global EMAC model with atmospheric chemistry and surface compartments coupled, we investigate the formation, abundance, and fate of two secondarily formed NPAHs, 2-nitrofluoranthene (2-NFLT) and 2-nitropyrene (2-NPYR). The default reactivity scenario, the model with the simplest interpretation of parameters from the literature, tends to overestimate both absolute concentrations and NPAH/PAH ratios at observational sites. Sensitivity scenarios indicate that NO2-dependent NPAH formation leads to better agreement between measured and predicted NPAH concentrations and that photodegradation is the most important loss process of 2-NFLT and 2-NPYR. The highest concentrations of 2-NFLT and 2-NPYR are found in regions with strong PAH emissions, but because of continued secondary formation from the PAH precursors, these two NPAHs are predicted to be spread across the globe.
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Affiliation(s)
- Jake Wilson
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Mega Octaviani
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | | | - Marco Wietzoreck
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Cornelius Zetzsch
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
- Bayreuth
Centre for Ecology and Environmental Research, University of Bayreuth, 95448 Bayreuth, Germany
| | - Ulrich Pöschl
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Thomas Berkemeier
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Gerhard Lammel
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
- Research
Centre for Toxic Compounds in the Environment, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
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11
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Li B, Zhang TS, Xue J, Xie BB, Fang WH, Shen L. Theoretical studies on the photochemistry of 2-nitrofluorene in the gas phase and acetonitrile solution. Phys Chem Chem Phys 2020; 22:16772-16782. [PMID: 32662496 DOI: 10.1039/d0cp01969k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The photophysical and photochemical mechanisms of 2-nitrofluorene (2-NF) in the gas phase and acetonitrile solution have been studied theoretically. Upon ∼330 nm irradiation to the first bright state (1ππ*), the 2-NF system can decay to triplet excited states via rapid intersystem crossing (ISC) processes through different surface crossing points or to the ground state via an ultrafast internal conversion (IC) process through the S1/S0 conical intersection. The 1nπ* dark state will serve as a bridge when the system leaves the Franck-Condon (FC) region and approaches to the S1 minimum. The molecule maintains a planar geometry during the excited-state relaxation processes. The differences on excitation properties such as electronic configurations and spin-orbit coupling (SOC) interactions between those in the gas phase and acetonitrile solution cannot be neglected, indicating possible changes on the efficiency of the related ISC processes for the 2-NF system in solution. Once arrived at the T1 state, it would further decay to the S0 state or photodegrade into the Ar-O˙ and NO˙ free radicals. During the intramolecular rearrangement process, the twisting of the nitro group out of the aromatic-ring plane is regarded as a critical structural variation for the photodegradation of the 2-NF system. The free radicals finally form through oxaziridine-type intermediate and transition state structures. The present work provides important mechanistic insights to the photochemistry of nitro-substituted polyaromatic compounds.
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Affiliation(s)
- Bo Li
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
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12
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Giussani A, Worth GA. How important is roaming in the photodegradation of nitrobenzene? Phys Chem Chem Phys 2020; 22:15945-15952. [DOI: 10.1039/d0cp02077j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three pathways have been found for the formation of NO from nitrobenzene photodegradation that lead to either low or high translational energy, with a roaming mechanism involved at high excitation energies.
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Affiliation(s)
- Angelo Giussani
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Graham A. Worth
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
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13
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Zobel JP, González L. Nonadiabatic Dynamics Simulation Predict Intersystem Crossing in Nitroaromatic Molecules on a Picosecond Time Scale. CHEMPHOTOCHEM 2019; 3:833-845. [PMID: 31681833 PMCID: PMC6813632 DOI: 10.1002/cptc.201900108] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 05/06/2019] [Indexed: 12/19/2022]
Abstract
Previous time-resolved spectroscopic experiments and static quantum-chemical calculations attributed nitronaphthalene derivatives one of the fastest time scales for intersystem crossing within organic molecules, reaching the 100 fs mark. Nonadiabatic dynamics simulations on three nitronaphthalene derivatives challenge this view, showing that the experimentally observed ∼100 fs process corresponds to internal conversion in the singlet manifolds. Intersystem crossing, instead, takes place on a longer time scale of ∼1 ps. The dynamics simulations further reveal that the spin transitions occur via two distinct pathways with different contribution for the three systems, which are determined by electronic factors and the torsion of the nitro group. This study, therefore, indicates that the existence of sub-picosecond intersystem crossing in other nitroaromatic molecules should be questioned.
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Affiliation(s)
- J. Patrick Zobel
- Division of Theoretical Chemistry, KemicentrumLund UniversityP.O. Box 124SE-221 00LundSweden
| | - Leticia González
- Institute of Theoretical ChemistryUniversity of ViennaWähringer Straße 17A-1090ViennaAustria
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14
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Sun H, Wang M, Nan Y, Han M, Lu H. The Kinetics and Mechanisms for Photodegradation of Nitrated Polycyclic Aromatic Hydrocarbons on Lettuce Leaf Surfaces: An In Vivo Study. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:8452-8458. [PMID: 31294967 DOI: 10.1021/acs.jafc.9b02326] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Insights into the environmental fates of nitrated polycyclic aromatic hydrocarbons (NPAHs) in edible vegetables are of great significance for better evaluating human exposure to NPAHs through the dietary pathway. In this work, a fluorescence quenching method using graphene quantum dots as a fluorescent probe was first applied for the in vivo determination of 9-nitroanthracene (9-NAnt) and 1-nitropyrene (1-NPyr) adsorbed on the leaf surfaces of living lettuce (Lactuca sativa L.) seedlings. Moreover, the photolysis kinetics and mechanisms of the two adsorbed NPAHs were discussed. The photodegradation kinetics followed the pseudo-first-order equation, and the photodegradation half-life of 1-NPyr (7.4 ± 0.2 h) was greater than that of 9-NAnt (2.3 ± 0.1 h). Anthraquinone and pyrenediones were identified to be the main photolytic products of 9-NAnt and 1-NPyr, respectively. Intramolecular rearrangement was the most reasonable mechanism for the NPAH photolysis. The photolysis-driven degradation exhibited a key role in scavenging NPAHs from the vegetable leaf, indicating the reduction of NPAH transportation in the food chain.
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Affiliation(s)
- Haifeng Sun
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
- Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province , Taiyuan 030031 , P. R. China
| | - Meng Wang
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
| | - Yanli Nan
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
| | - Ming Han
- College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China
| | - Haoliang Lu
- Key Laboratory of Ministry of Coastal and Wetland Ecosystem , Xiamen University , Xiamen 361102 , P. R. China
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15
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Giussani A, Worth GA. Similar chemical structures, dissimilar triplet quantum yields: a CASPT2 model rationalizing the trend of triplet quantum yields in nitroaromatic systems. Phys Chem Chem Phys 2019; 21:10514-10522. [DOI: 10.1039/c9cp00705a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
S1/S0 accessibility strongly influences the triplet quantum yields of nitronaphthalenes.
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Affiliation(s)
- Angelo Giussani
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Graham A. Worth
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
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16
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Zobel JP, Nogueira JJ, González L. Mechanism of Ultrafast Intersystem Crossing in 2-Nitronaphthalene. Chemistry 2018; 24:5379-5387. [PMID: 29377370 PMCID: PMC5947663 DOI: 10.1002/chem.201705854] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Indexed: 01/10/2023]
Abstract
Nitronaphthalene derivatives efficiently populate their electronically excited triplet states upon photoexcitation through ultrafast intersystem crossing (ISC). Despite having been studied extensively by time-resolved spectroscopy, the reasons behind their ultrafast ISC remain unknown. Herein, we present the first ab initio nonadiabatic molecular dynamics study of a nitronaphthalene derivative, 2-nitronaphthalene, including singlet and triplet states. We find that there are two distinct ISC reaction pathways involving different electronic states at distinct nuclear configurations. The high ISC efficiency is explained by the very small electronic and nuclear alterations that the chromophore needs to undergo during the singlet-triplet transition in the dominating ISC pathway after initial dynamics in the singlet manifold. The insights gained in this work are expected to shed new light on the photochemistry of other nitro polycyclic aromatic hydrocarbons that exhibit ultrafast intersystem crossing.
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Affiliation(s)
- J. Patrick Zobel
- Institute of Theoretical Chemistry, Faculty of ChemistryUniversity of ViennaWähringer Straße 171090ViennaAustria
| | - Juan J. Nogueira
- Institute of Theoretical Chemistry, Faculty of ChemistryUniversity of ViennaWähringer Straße 171090ViennaAustria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of ChemistryUniversity of ViennaWähringer Straße 171090ViennaAustria
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17
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Penfold TJ, Gindensperger E, Daniel C, Marian CM. Spin-Vibronic Mechanism for Intersystem Crossing. Chem Rev 2018; 118:6975-7025. [DOI: 10.1021/acs.chemrev.7b00617] [Citation(s) in RCA: 401] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Thomas J. Penfold
- Chemistry - School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon-Tyne NE1 7RU, United Kingdom
| | - Etienne Gindensperger
- Laboratoire de Chimie Quantique, Institut de Chimie UMR-7177, CNRS - Université de Strasbourg, 1 Rue Blaise Pascal 67008 Strasbourg, France
| | - Chantal Daniel
- Laboratoire de Chimie Quantique, Institut de Chimie UMR-7177, CNRS - Université de Strasbourg, 1 Rue Blaise Pascal 67008 Strasbourg, France
| | - Christel M. Marian
- Institut für Theoretische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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18
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Yang M, Zhang T, Xue J, Zheng X. Ab Initio Study of Decay Dynamics of 1-Nitronaphthalene Initiated from the S 2(ππ* + n NOπ*) State. J Phys Chem A 2018; 122:2732-2738. [PMID: 29488758 DOI: 10.1021/acs.jpca.7b11003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Irradiation of nitro-PAHs in solution at ambient conditions leads to formation of its lowest excited triplet, dissociation intermediates nitrogen oxide (NO•) and aryloxy radical (Ar-O•). Experimental and theoretical studies demonstrated that Franck-Condon excited singlet state SFC(ππ*) to a receiver, higher-energy triplet state Tn(nπ*) controlled the ultrafast population of the triplet state and, hence, the slight fluorescence yield of nitronaphthalenes. However, the detailed information about the curve-crossings of potential energy surfaces and the major channels for forming T1 species and Ar-O• radical were unclear. Here, by using the CASSCF//CASPT2 method, an efficient decay channel is revealed: S2-FC-1NN → S2-MIN-1NN or S2T3-MIN-1NN → T3-MIN-1NN or T3T2-MIN-1NN→ T2-MIN-1NN or T2T1-MIN-1NN → T1-MIN-1NN. This explains the high yield of T1-1NN species and minor yield of Ar-O• and NO• radicals. The calculation results suggest the bifurcation processes take place predominantly after the internal conversion to the T1-1NN state via T2T1-MIN-1NN, one leads to T1-MIN-1NN, while the other to T1-MIN-ISO to produce Ar-O• and NO• radicals.
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Affiliation(s)
- Meng Yang
- Department of Chemistry , Zhejiang Sci-Tech University , Hangzhou 310018 , P. R. China
| | - Tengshuo Zhang
- Department of Chemistry , Zhejiang Sci-Tech University , Hangzhou 310018 , P. R. China
| | - Jiadan Xue
- Department of Chemistry , Zhejiang Sci-Tech University , Hangzhou 310018 , P. R. China
| | - Xuming Zheng
- Department of Chemistry , Zhejiang Sci-Tech University , Hangzhou 310018 , P. R. China
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19
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Zhang D, Jin P, Yang M, Du Y, Zheng X, Xue J. Intermolecular Hydrogen Abstraction from Hydroxy Group and Alkyl by T 1(ππ*) of 1-Chloro-4-nitronaphthalene. J Phys Chem A 2018; 122:1831-1837. [PMID: 29432008 DOI: 10.1021/acs.jpca.7b11146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nanosecond transient absorption and theoretical calculations have been used to investigate the intermolecular hydrogen abstractions from alcohols and 1-naphthol by the lowest excited triplet (T1) of 1-chloro-4-nitronaphthalene upon excitation of the compound in organic solvents. The hydrogen abstraction of T1 from hydroxy group of 1-naphthol takes place through an electron transfer followed by a proton transfer through hydrogen bonding interaction with rate constants of ∼109 M-1 s-1. Hydrogen-bonding is crucial in this process, indicated by the observation of a half reduction for T1 yield when increasing the concentration of 1-naphthol. The hydrogen abstraction in this way can be decelerated by increasing solvent polarity and hydrogen-bonding donor ability. The T1 of 1-chloro-4-nitronaphthalene can undergo one-step H atom abstraction from alkyl hydrogen in alcoholic solvents, with rate constants of ∼104 M-1 s-1, and produce radical intermediates with the absorption maximum at 368 nm. DFT calculation results indicate both oxygens of the nitro group are active sites for hydrogen abstraction, and the difference of activation barriers for formation of two radical isomers is only 1.0 kcal/mol.
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Affiliation(s)
- Di Zhang
- Department of Chemsitry, Zhejiang Sci-Tech University , Hangzhou 310018, China
| | - Peipei Jin
- Department of Chemsitry, Zhejiang Sci-Tech University , Hangzhou 310018, China
| | - Meng Yang
- Department of Chemsitry, Zhejiang Sci-Tech University , Hangzhou 310018, China
| | - Yong Du
- Center for THz Research, China Jiliang University , Hangzhou 310018, China
| | - Xuming Zheng
- Department of Chemsitry, Zhejiang Sci-Tech University , Hangzhou 310018, China
| | - Jiadan Xue
- Department of Chemsitry, Zhejiang Sci-Tech University , Hangzhou 310018, China
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20
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Giussani A, Conti I, Nenov A, Garavelli M. Photoinduced formation mechanism of the thymine–thymine (6–4) adduct in DNA; a QM(CASPT2//CASSCF):MM(AMBER) study. Faraday Discuss 2018; 207:375-387. [DOI: 10.1039/c7fd00202e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Out-of-plane puckering of the C4′ atom forming a new CC bond seems essential for oxetane formation.
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Affiliation(s)
- Angelo Giussani
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
| | - Irene Conti
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
- Dipartimento di Chimica Industriale “Toso Montanari”
| | - Artur Nenov
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
- Dipartimento di Chimica Industriale “Toso Montanari”
| | - Marco Garavelli
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
- Dipartimento di Chimica Industriale “Toso Montanari”
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21
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Giussani A, Worth GA. Insights into the Complex Photophysics and Photochemistry of the Simplest Nitroaromatic Compound: A CASPT2//CASSCF Study on Nitrobenzene. J Chem Theory Comput 2017; 13:2777-2788. [DOI: 10.1021/acs.jctc.6b01149] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Angelo Giussani
- School
of Chemistry, University of Birmingham, Edgbaston B15 2TT, U.K
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Graham A. Worth
- School
of Chemistry, University of Birmingham, Edgbaston B15 2TT, U.K
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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22
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Zobel JP, Nogueira JJ, González L. The IPEA dilemma in CASPT2. Chem Sci 2017; 8:1482-1499. [PMID: 28572908 PMCID: PMC5452265 DOI: 10.1039/c6sc03759c] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/23/2016] [Indexed: 12/22/2022] Open
Abstract
Multi-configurational second order perturbation theory (CASPT2) has become a very popular method for describing excited-state properties since its development in 1990. To account for systematic errors found in the calculation of dissociation energies, an empirical correction applied to the zeroth-order Hamiltonian, called the IPEA shift, was introduced in 2004. The errors were attributed to an unbalanced description of open-shell versus closed-shell electronic states and is believed to also lead to an underestimation of excitation energies. Here we show that the use of the IPEA shift is not justified and the IPEA should not be used to calculate excited states, at least for organic chromophores. This conclusion is the result of three extensive analyses. Firstly, we survey the literature for excitation energies of organic molecules that have been calculated with the unmodified CASPT2 method. We find that the excitation energies of 356 reference values are negligibly underestimated by 0.02 eV. This value is an order of magnitude smaller than the expected error based on the calculation of dissociation energies. Secondly, we perform benchmark full configuration interaction calculations on 137 states of 13 di- and triatomic molecules and compare the results with CASPT2. Also in this case, the excited states are underestimated by only 0.05 eV. Finally, we perform CASPT2 calculations with different IPEA shift values on 309 excited states of 28 organic small and medium-sized organic chromophores. We demonstrate that the size of the IPEA correction scales with the amount of dynamical correlation energy (and thus with the size of the system), and gets immoderate already for the molecules considered here, leading to an overestimation of the excitation energies. It is also found that the IPEA correction strongly depends on the size of the basis set. The dependency on both the size of the system and of the basis set, contradicts the idea of a universal IPEA shift which is able to compensate for systematic CASPT2 errors in the calculation of excited states.
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Affiliation(s)
- J Patrick Zobel
- Institute of Theoretical Chemistry , Faculty of Chemistry , University of Vienna , Währinger Straße 17 , 1090 Vienna , Austria . ;
| | - Juan J Nogueira
- Institute of Theoretical Chemistry , Faculty of Chemistry , University of Vienna , Währinger Straße 17 , 1090 Vienna , Austria . ;
| | - Leticia González
- Institute of Theoretical Chemistry , Faculty of Chemistry , University of Vienna , Währinger Straße 17 , 1090 Vienna , Austria . ;
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23
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Giussani A, Segarra-Martí J, Nenov A, Rivalta I, Tolomelli A, Mukamel S, Garavelli M. Spectroscopic fingerprints of DNA/RNA pyrimidine nucleobases in third-order nonlinear electronic spectra. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1867-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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24
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Nenov A, Giussani A, Segarra-Martí J, Jaiswal VK, Rivalta I, Cerullo G, Mukamel S, Garavelli M. Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy. J Chem Phys 2015; 142:212443. [PMID: 26049463 DOI: 10.1063/1.4921016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040-1041, 295-303 (2014)]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide conformational dependent fingerprints in dimeric systems, the performances of the selected reduced level of calculations have been tested in the construction of 2D electronic spectra for the in vacuo adenine monomer and the unstacked adenine homodimer, thereby exciting the Lb/La transitions with the pump pulse pair and probing in the Vis to near ultraviolet spectral window.
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Affiliation(s)
- Artur Nenov
- Dipartimento di Chimica "G. Ciamician," Università di Bologna, Via Selmi 2, IT-40126 Bologna, Italy
| | - Angelo Giussani
- Dipartimento di Chimica "G. Ciamician," Università di Bologna, Via Selmi 2, IT-40126 Bologna, Italy
| | - Javier Segarra-Martí
- Dipartimento di Chimica "G. Ciamician," Università di Bologna, Via Selmi 2, IT-40126 Bologna, Italy
| | - Vishal K Jaiswal
- Dipartimento di Chimica "G. Ciamician," Università di Bologna, Via Selmi 2, IT-40126 Bologna, Italy
| | - Ivan Rivalta
- Université de Lyon, CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, IFN-CNR, Piazza Leonardo Da Vinci 32, IT-20133 Milano, Italy
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
| | - Marco Garavelli
- Dipartimento di Chimica "G. Ciamician," Università di Bologna, Via Selmi 2, IT-40126 Bologna, Italy
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