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Parsons BF, Hulce MR, Ackerman JR, Reardon KA, Pappas ES, Kettler LE. Ultraviolet Excitation of M-O 2 (M = Phenalenone, Fluorenone, Pyridine, & Acridine) Complexes Resulting in 1O 2. J Phys Chem A 2024; 128:2971-2981. [PMID: 38579334 DOI: 10.1021/acs.jpca.4c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
In our experiment, a trace amount of an organic molecule (M = 1H-phenalen-1-one, 9-fluorenone, pyridine, or acridine) was seeded into a gas mix consisting of 3% O2 with a rare gas buffer (He or Ar) and then supersonically expanded. We excited the resulting molecular beam with ultraviolet light at either 355 nm (1H-phenalen-1-one, 9-fluorenone, or acridine) or 266 nm (pyridine) and used resonance enhanced multiphoton ionization (REMPI) spectroscopy to probe for the formation of O2 in the a-1Δg state, 1O2. For all systems, the REMPI spectra demonstrate that ultraviolet excitation results in the formation of 1O2 and the oxygen product is confirmed to be in the ground vibrational state and with an effective rotational temperature below 80 K. We then recorded the velocity map ion image of the 1O2 product. From the ion images, we determined the center-of-mass translational energy distribution, P(ET), assuming photodissociation of a bimolecular M-O2 complex. We also report results from electronic structure calculations that allow for a determination of the M-O2 ground state binding energy. We use the complex binding energy, the energy to form 1O2, and the adiabatic triplet energy for each organic molecule to determine the available energy following photodissociation. For dissociation of a bimolecular complex, this available energy may be partitioned into either center-of-mass recoil or internal degrees of freedom of the organic moiety. We use the available energy to generate a Prior distribution, which predicts statistical energy partitioning during dissociation. For low available energies, less than 0.2 eV, we find that the statistical prediction is in reasonable agreement with the experimental observations. However, at higher available energies, the experimental distribution is biased to lower center-of-mass kinetic energies compared with the statistical prediction, which suggests the complex undergoes vibrational predissociation.
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Affiliation(s)
- Bradley F Parsons
- Department of Chemistry and Biochemistry 2500 California Plaza, Creighton University, Omaha, Nebraska 68178, United States
| | - Martin R Hulce
- Department of Chemistry and Biochemistry 2500 California Plaza, Creighton University, Omaha, Nebraska 68178, United States
| | - John R Ackerman
- Department of Chemistry and Biochemistry 2500 California Plaza, Creighton University, Omaha, Nebraska 68178, United States
| | - Kylie A Reardon
- Department of Chemistry and Biochemistry 2500 California Plaza, Creighton University, Omaha, Nebraska 68178, United States
| | - Emerson S Pappas
- Department of Chemistry and Biochemistry 2500 California Plaza, Creighton University, Omaha, Nebraska 68178, United States
| | - Lauren E Kettler
- Department of Chemistry and Biochemistry 2500 California Plaza, Creighton University, Omaha, Nebraska 68178, United States
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Bag S, Chandra S, Ghosh J, Bera A, Bernstein ER, Bhattacharya A. The attochemistry of chemical bonding. INT REV PHYS CHEM 2021. [DOI: 10.1080/0144235x.2021.1976499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Sampad Bag
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
| | - Sankhabrata Chandra
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
| | - Jayanta Ghosh
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
| | - Anupam Bera
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
| | | | - Atanu Bhattacharya
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
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Booth RS, Annesley CJ. Photoinduced Intermolecular Electron Transfer in Gas Phase Ion Pairs of the 1-Ethyl-3-methylimidazolium Cation and the Bis(trifluoromethylsulfonyl)imide Anion. J Phys Chem A 2020; 124:9683-9691. [PMID: 33185452 DOI: 10.1021/acs.jpca.0c06018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, the UV photodissociation of gas phase ion pairs of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim]+[tf2n]-, is shown to proceed primarily through radical intermediates. [emim]+[tf2n]- ion pairs have been shown previously to undergo two-photon-dependent dissociation, but the mechanisms of this have not been probed in detail. By employing a two-laser pump probe spectroscopy and time-dependent density functional theory (TD-DFT) calculations, we have illustrated that one of the major UV photodissociation pathways in [emim]+[tf2n]- ion pairs is an intermolecular electron transfer wherein the anion transfers an electron to the cation resulting in two neutral open-shelled products. These products were observable for at least 1.6 μs post photodissociation, the experimental limit, via detection of the [emim]+ cation. This data demonstrates that the likely photoproducts of [emim]+[tf2n]- UV photodissociation are two neutral species that separate spatially, demonstrated through lack of observed relaxation pathways such as electron recombination. TD-DFT and frontier molecular orbital analysis calculations at the MN15/6-311++G(d,p) level are employed to aid in identifying excited state characteristics and support the interpretations of the experimental data. The energetic onset of the intermolecular electron transfer is consistent with previously observed [emim]+[tf2n]- absorption spectra in the bulk and gas phases. The similarities between bulk and gas phase UV spectra imply that this electron-transfer pathway may be a major photodissociation channel in both phases.
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Affiliation(s)
- Ryan S Booth
- Institute for Scientific Research, Boston College, Chestnut Hill, Boston, Massachusetts 02467, United States
| | - Christopher J Annesley
- Space Vehicles Directorate, Air Force Research Laboratory, Kirtland AFB, Albuquerque, New Mexico 87117, United States
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Pyryaeva AP, Ershov KS, Kochubei SA, Baklanov AV. Singlet Oxygen Generation via UV-A, -B, and -C Photoexcitation of Isoprene-Oxygen (C 5H 8-O 2) Encounter Complexes in the Gas Phase. J Phys Chem A 2020; 124:8469-8477. [PMID: 32986424 DOI: 10.1021/acs.jpca.0c07509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The formation of singlet oxygen 1O2 provided by the photoexcitation of the encounter complexes of isoprene with oxygen (C5H8-O2) in the gas phase within the spectral region 253.5-355 nm has been observed at the elevated pressure of oxygen. Singlet oxygen has been detected with its NIR luminescence centered near 1.27 μm. The photogeneration of 1O2 is found to be a one-photon process. In the UV-C region (253-278 nm) the quantum yield of 1O2 is measured. This yield of 1O2 is governed mainly by photoexcitation of O2 molecules to the Herzberg III (3Δu) state via enhanced absorption by C5H8-O2 collision complexes. So excited triplet O2 gives rise to singlet oxygen because of triplet-triplet annihilation in the collisions with unexcited O2 molecules. In the UV-B (308 nm) region the appearance of 1O2 is attributed to the excitation of a double spin-flip (DSF) transition in complex C5H8-O2. In the UV-A region (355 nm) besides DSF the O2-assisted T1 ← S0 excitation of isoprene to the triplet state takes place, which is a sensitizer of 1O2 formation. The contribution of the encounter complexes C5H8-O2 to the production of singlet oxygen and to the lifetime of isoprene in the Earth's troposphere are estimated.
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Affiliation(s)
- Alexandra P Pyryaeva
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Kirill S Ershov
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
| | - Sergei A Kochubei
- Institute of Semiconductor Physics, ac. Lavrent'yev ave., 13, Novosibirsk 630090, Russia
| | - Alexey V Baklanov
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090, Russia.,Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
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Baklanov AV, Parker DH. Weakly Bound Environment of Molecular Oxygen as a Catalyst of Photooxidation. KINETICS AND CATALYSIS 2020. [DOI: 10.1134/s0023158420020019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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REMPI detection of singlet oxygen 1O2 arising from UV-photodissociation of van der Waals complex isoprene-oxygen C5H8-O2. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.12.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Patros KM, Mann JE, Jarrold CC. Photoelectron Imaging Spectra of O 2-·VOC and O 4-·VOC Complexes. J Phys Chem A 2016; 120:7828-7838. [PMID: 27648607 DOI: 10.1021/acs.jpca.6b07107] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The anion photoelectron imaging spectra of O2-·VOC and O4-·VOC (VOC = hexane, isoprene, benzene, and benzene-d6) complexes measured using 3.49 eV photon energy, along with the results of ab initio and density functional theory results are reported and analyzed. Photodetachment of these anionic complexes accesses neutrals that model collision complexes, offering a probe of the effects of symmetry-breaking collision events on the electronic structure of normally transparent neutral molecules. The energies of O2-·VOC spectral features compared to the bare O2- indicate that photodetachment of the anion accesses a modestly repulsive region of the O2-VOC potential energy surface, with subtle VOC dependence on the relative energies of the O2 (X 3Σg-)·VOC ground state and O2 (a 1Δg)·VOC excited state. In contrast, a significantly higher intensity of the transition to the O2 (a 1Δg)·VOC excited state relative to the O2 (X 3Σg-)·VOC ground state is observed for VOC = benzene, with a less pronounced effect observed for VOC = isoprene. Similar spectral effects are observed in the O4-·benzene and O4-·isoprene PE spectra. Several explanations are considered, with involvement of a temporary anion state emerging as the most plausible.
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Affiliation(s)
- Kellyn M Patros
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jennifer E Mann
- Physical Electronics , 18725 Lake Drive East, Chanhassen, Minnesota 55317, United States
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Bogomolov AS, Kochubei SA, Baklanov AV. Oxygen-assisted excitation of methyl iodide as a test of double spin-flip transition in van der Waals complex CH3I-O2. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.08.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bogdanchikov GA, Baklanov AV. Calculations of the geometry and binding energy of the van der Waals complex of ethylene with oxygen C2H4–O2. J STRUCT CHEM+ 2015. [DOI: 10.1134/s0022476615050224] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Baklanov AV, Bogomolov AS, Pyryaeva AP, Bogdanchikov GA, Kochubei SA, Farooq Z, Parker DH. Singlet oxygen photogeneration from X–O2 van der Waals complexes: double spin-flip vs. charge-transfer mechanism. Phys Chem Chem Phys 2015; 17:28565-73. [DOI: 10.1039/c5cp03129j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The channel of singlet oxygen O2(1Δg) photogeneration from van der Waals complexes of oxygen X–O2 has been investigated to discriminate between two mechanisms based on charge-transfer or double spin-flip transitions.
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Affiliation(s)
- Alexey V. Baklanov
- Institute of Chemical Kinetics and Combustion
- Novosibirsk 630090
- Russia
- Novosibirsk State University
- Novosibirsk 630090
| | | | - Alexandra P. Pyryaeva
- Institute of Chemical Kinetics and Combustion
- Novosibirsk 630090
- Russia
- Novosibirsk State University
- Novosibirsk 630090
| | - Georgii A. Bogdanchikov
- Institute of Chemical Kinetics and Combustion
- Novosibirsk 630090
- Russia
- Novosibirsk State University
- Novosibirsk 630090
| | | | - Zahid Farooq
- Institute for Molecules and Materials
- Radboud University Nijmegen
- 6525 ED Nijmegen
- The Netherlands
| | - David H. Parker
- Institute for Molecules and Materials
- Radboud University Nijmegen
- 6525 ED Nijmegen
- The Netherlands
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Oxygen-assisted enhancement of H atom UV-photogeneration from hydrocarbons in van der Waals complexes RH–O2. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2012.12.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Vidma KV, Frederix PWJM, Parker DH, Baklanov AV. Photodissociation of van der Waals clusters of isoprene with oxygen, C5H8-O2, in the wavelength range 213-277 nm. J Chem Phys 2012; 137:054305. [PMID: 22894346 DOI: 10.1063/1.4737856] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The speed and angular distribution of O atoms arising from the photofragmentation of C(5)H(8)-O(2), the isoprene-oxygen van der Waals complex, in the wavelength region of 213-277 nm has been studied with the use of a two-color dissociation-probe method and the velocity map imaging technique. Dramatic enhancement in the O atoms photo-generation cross section in comparison with the photodissociation of individual O(2) molecules has been observed. Velocity map images of these "enhanced" O atoms consisted of five channels, different in their kinetic energy, angular distribution, and wavelength dependence. Three channels are deduced to be due to the one-quantum excitation of the C(5)H(8)-O(2) complex into the perturbed Herzberg III state ((3)Δ(u)) of O(2). This excitation results in the prompt dissociation of the complex giving rise to products C(5)H(8)+O+O when the energy of exciting quantum is higher than the complex photodissociation threshold, which is found to be 41740 ± 200 cm(-1) (239.6±1.2 nm). This last threshold corresponds to the photodissociation giving rise to an unexcited isoprene molecule. The second channel, with threshold shifted to the blue by 1480 ± 280 cm(-1), corresponds to dissociation with formation of rovibrationally excited isoprene. A third channel was observed at wavelengths up to 243 nm with excitation below the upper photodissociation threshold. This channel is attributed to dissociation with the formation of a bound O atom C(5)H(8)-O(2) + hv → C(5)H(8)-O(2)((3)Δ(u)) → C(5)H(8)O + O and/or to dissociation of O(2) with borrowing of the lacking energy from incompletely cooled complex internal degrees of freedom C(5)H(8)*-O(2) + hv → C(5)H(8)*-O(2)((3)Δ(u)) → C(5)H(8) + O + O. The kinetic energy of the O atoms arising in two other observed channels corresponds to O atoms produced by photodissociation of molecular oxygen in the excited a (1)Δ(g) and b (1)Σ(g)(+) singlet states as the precursors. This indicates the formation of singlet oxygen O(2)(a (1)Δ(g)) and O(2)(b (1)Σ(g)(+)) after excitation of the C(5)H(8)-O(2) complex. Cooperative excitation of the complex with a simultaneous change of the spin of both partners (1)X-(3)O(2) + hν → (3)X-(1)O(2) → (3)X + (1)O(2) is suggested as a source of singlet oxygen O(2)(a (1)Δ(g)) and O(2)(b (1)Σ(g)(+)). This cooperative excitation is in agreement with little or no vibrational excitation of O(2)(a (1)Δ(g)), produced from the C(5)H(8)-O(2) complex as studied in the current paper as well as from the C(3)H(6)-O(2) and CH(3)I-O(2) complexes reported in our previous paper [Baklanov et al., J. Chem. Phys. 126, 124316 (2007)]. The formation of O(2)(a (1)Δ(g)) from C(5)H(8)-O(2) was observed at λ(pump) = 213-277 nm with the yield going down towards the long wavelength edge of this interval. This spectral profile is interpreted as the red-side wing of the band of a cooperative transition (1)X-(3)O(2) + hν → (3)X(T(2))-(1)O(2)(a (1)Δ(g)) in the C(5)H(8)-O(2) complex.
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Affiliation(s)
- Konstantin V Vidma
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 ED Nijmegen, The Netherlands
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Trushina AP, Goldort VG, Kochubei SA, Baklanov AV. Quantum Yield and Mechanism of Singlet Oxygen Generation via UV Photoexcitation of O2–O2 and N2–O2 Encounter Complexes. J Phys Chem A 2012; 116:6621-9. [DOI: 10.1021/jp301471e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Aleksandra P. Trushina
- Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090,
Russia
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk
630090, Russia
| | - Veniamin G. Goldort
- Institute of Semiconductor Physics, Lavrentiev Ave. 13, Novosibirsk
630090, Russia
| | - Sergei A. Kochubei
- Institute of Semiconductor Physics, Lavrentiev Ave. 13, Novosibirsk
630090, Russia
| | - Alexey V. Baklanov
- Institute of Chemical Kinetics and Combustion, Institutskaya Str. 3, Novosibirsk 630090,
Russia
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk
630090, Russia
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Li Y, Liu S, Chen M, Ma F. Photoinduced intermolecular and intramolecular charge transfer in the mixed coaggregates of pyrazoline and dicyanonaphthalene. J Photochem Photobiol A Chem 2009. [DOI: 10.1016/j.jphotochem.2009.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Baklanov AV, Bogdanchikov GA, Vidma KV, Chestakov DA, Parker DH. Cluster-enhanced X–O2 photochemistry (X=CH3I, C3H6, C6H12, and Xe). J Chem Phys 2007; 126:124316. [PMID: 17411132 DOI: 10.1063/1.2710268] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The effect of a local environment on the photodissociation of molecular oxygen is investigated in the van der Waals complex X-O(2) (X=CH(3)I, C(3)H(6), C(6)H(12), and Xe). A single laser operating at wavelengths around 226 nm is used for both photodissociation of the van der Waals complex and simultaneous detection of the O((3)P(J),J=2,1,0) atom photoproduct via (2+1) resonance enhanced multiphoton ionization. The kinetic energy distribution (KED) and angular anisotropy of the product O atom recoil in this dissociation are measured using the velocity map imaging technique configured for either full ("crush") or partial ("slice") detection of the three-dimensional O((3)P(J)) atom product Newton sphere. The measured KED and angular anisotropy reveal a distinct difference in the mechanism of O atom generation from an X-O(2) complex compared to a free O(2) molecule. The authors identify two one-photon excitation pathways, the relative importance of which depends on IPx, the ionization potential of the X partner. One pathway, observed for all complexes independent of IPx, involves a direct transition to the perturbed covalent state X-O(2)(A'(3)Delta(u)) with excitation localized on the O(2) subunit. The predominantly perpendicular character of this channel relative to the laser polarization detection, together with data on the structure of the complex, allows us to confirm that X partner induced admixing of an X(+)-O(2) (-) charge transfer (CT) state is the perturbing factor resulting in the well-known enhancement of photoabsorption within the Herzberg continuum of molecular oxygen. The second excitation pathway, observed for X-O(2) complexes with X=CH(3)I and C(3)H(6), involves direct excitation into the (3)(X(+)-O(2) (-)) CT state of the complex. The subsequent photodissociation of this CT state by the same laser pulse gives rise to the superoxide anion O(2) (-), which then photodissociates, providing fast (0.69 eV) O atoms with a parallel image pattern. Products from the photodissociation of singlet oxygen O(2)(b (1)Sigma(g) (+)) are also observed when the CH(3)I-O(2) complex was irradiated. Potential energy surfaces (PES) for the ground and relevant excited states of the X-O(2) complex have been constructed for CH(3)I-O(2) using the results of CASSCF calculations for the ground and CT states of the complex as well as literature data on PES of the subunits. These model potential energy surfaces allowed us to interpret all of the observed O((3)P(J)) atom production channels.
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Affiliation(s)
- Alexey V Baklanov
- Institute of Chemical Kinetics and Combustion, Institutskaja Street 3, Novosibirsk, Russia
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Sun M, Pullerits T, Kjellberg P, Beenken WJD, Han K. Control of Emission by Intermolecular Fluorescence Resonance Energy Transfer and Intermolecular Charge Transfer. J Phys Chem A 2006; 110:6324-8. [PMID: 16686468 DOI: 10.1021/jp060275m] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Control of emission by intermolecular fluorescence resonant energy transfer (IFRET) and intermolecular charge transfer (ICT) is investigated with the quantum-chemistry method using two-dimensional (2D) and three-dimensional (3D) real space analysis methods. The work is based on the experiment of tunable emission from doped 1,3,5-triphenyl-2-pyrazoline (TPP) organic nanoparticles (Peng, A. D.; et al. Adv. Mater. 2005, 17, 2070). First, the excited-state properties of the molecules, which are studied (TPP and DCM) in that experiment, are investigated theoretically. The results of the 2D site representation reveal the electron-hole coherence and delocalization size on the excitation. The results of 3D cube representation analysis reveal the orientation and strength of the transition dipole moments and intramolecular or intermolecular charge transfer. Second, the photochemical quenching mechanism via IFRET is studied (here "resonance" means that the absorption spectrum of TPP overlaps with the fluorescence emission spectrum of DCM in the doping system) by comparing the orbital energies of the HOMO (highest occupied molecular orbital) and the LUMO (lowest unoccupied molecular orbital) of DCM and TPP in absorption and fluorescence. Third, for the DCM-TPP complex, the nonphotochemical quenching mechanism via ICT is investigated. The theoretical results show that the energetically lowest ICT state corresponds to a pure HOMO-LUMO transition, where the densities of the HOMO and LUMO are strictly located on the DCM and TPP moieties, respectively. Thus, the lowest ICT state corresponds to an excitation of an electron from the HOMO of DCM to the LUMO of TPP.
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Affiliation(s)
- Mengtao Sun
- Department of Chemical Physics, Lund University, Lund SE22100, Sweden.
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Paterson MJ, Christiansen O, Jensen F, Ogilby PR. Overview of Theoretical and Computational Methods Applied to the Oxygen–Organic Molecule Photosystem. Photochem Photobiol 2006; 82:1136-60. [PMID: 16643088 DOI: 10.1562/2006-03-17-ir-851] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The challenges of using modern theoretical and computational tools to model the unique features of the oxygen-organic molecule photosystem are discussed from a historical and pedagogical perspective. This review is written for the novice, but the problems formulated should stimulate the expert.
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Affiliation(s)
- Martin J Paterson
- Department of Chemistry, University of Aarhus, Arhus, DK-8000, Denmark
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Affiliation(s)
- T E Dermota
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Parsons BF, Chandler DW. On the Dissociation of van der Waals Clusters of X2−Cyclohexane (X = O, Cl) Following Charge-Transfer Excitation in the Ultraviolet. J Phys Chem A 2003. [DOI: 10.1021/jp0301150] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bradley F. Parsons
- Sandia National Laboratories, Combustion Research Facility, Livermore, California 94550
| | - David W. Chandler
- Sandia National Laboratories, Combustion Research Facility, Livermore, California 94550
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