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Jarrold CC. Probing Anion-Molecule Complexes of Atmospheric Relevance Using Anion Photoelectron Detachment Spectroscopy. ACS PHYSICAL CHEMISTRY AU 2022; 3:17-29. [PMID: 36718261 PMCID: PMC9881448 DOI: 10.1021/acsphyschemau.2c00060] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 01/01/2023]
Abstract
Bimolecular reaction and collision complexes that drive atmospheric chemistry and contribute to the absorption of solar radiation are fleeting and therefore inherently challenging to study experimentally. Furthermore, primary anions in the troposphere are short lived because of a complicated web of reactions and complex formation they undergo, making details of their early fate elusive. In this perspective, the experimental approach of photodetaching mass-selected anion-molecule complexes or complex anions, which prepares neutrals in various vibronic states, is surveyed. Specifically, the application of anion photoelectron spectroscopy along with photoelectron-photofragment coincidence spectroscopy toward the study of collision complexes, complex anions in which a partial covalent bond is formed, and radical bimolecular reaction complexes, with relevance in tropospheric chemistry, will be highlighted.
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2
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Ru B, Hart CA, Mabbs R, Gozem S, Krylov AI, Sanov A. Dipole effects in the photoelectron angular distributions of the sulfur monoxide anion. Phys Chem Chem Phys 2022; 24:23367-23381. [PMID: 36129043 DOI: 10.1039/d2cp03337b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoelectron angular distributions (PADs) in SO- photodetachment using linearly polarized 355 nm (3.49 eV), 532 nm (2.33 eV), and 611 nm (2.03 eV) light were investigated via photoelectron imaging spectroscopy. The measurements at 532 and 611 nm access the X3Σ- and a1Δ electronic states of SO, whereas the measurements at 355 nm also access the b1Σ+ state. In aggregate, the photoelectron anisotropy parameter values follow the general trend with respect to electron kinetic energy (eKE) expected for π*-orbital photodetachment. The trend is similar to O2-, but the minimum of the SO- curve is shifted to smaller eKE. This shift is mainly attributed to the exit-channel interactions of the departing electron with the dipole moment of the neutral SO core, rather than the differing shapes of the SO- and O2- molecular orbitals. Of the several ab initio models considered, two approaches yield good agreement with the experiment: one representing the departing electron as a superposition of eigenfunctions of a point dipole-field Hamiltonian, and another describing the outgoing electron in terms of Coulomb waves originating from two separated charge centers, with a partial positive charge on the sulfur and an equal negative charge on the oxygen. These fundamentally related approaches support the conclusion that electron-dipole interactions in the exit channel of SO- photodetachment play an important role in shaping the PADs. While a similar conclusion was previously reached for photodetachment from σ orbitals of CN- (Hart, Lyle, Spellberg, Krylov, Mabbs, J. Phys. Chem. Lett., 2021, 12, 10086-10092), the present work includes the first extension of the dipole-field model to detachment from π* orbitals.
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Affiliation(s)
- Beverly Ru
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA.
| | - C Annie Hart
- Department of Chemistry, Washington University, Saint Louis, MO 63130, USA
| | - Richard Mabbs
- Department of Chemistry, Washington University, Saint Louis, MO 63130, USA
| | - Samer Gozem
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Andrei Sanov
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA.
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3
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Hashimoto Y, Saito K, Takayanagi T, Tachikawa H. Theoretical study of the dissociative photodetachment dynamics of the hydrated superoxide anion cluster. Phys Chem Chem Phys 2021; 23:16958-16965. [PMID: 34338247 DOI: 10.1039/d1cp02379a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The dissociative photodetachment of the hydrated superoxide anion cluster, O2-·H2O + hν → O2 + H2O + e-, is theoretically investigated using path-integral and ring-polymer molecular dynamics simulation methods, which can account for nuclear quantum effects. Full-dimensional potential energy surfaces for the anionic and lowest two neutral states (triplet and singlet spin states) are constructed based on extensive density-functional theory calculations. The calculated photoelectron spectrum agrees well with the experimental spectra measured for different photodetachment laser wavelengths. The calculated photoelectron-photofragment kinetic energy correlation spectrum also agrees well with previous experimental measurements. The dissociation mechanisms, including available energy partitioning and the importance of nuclear quantum effects in photodetachment, are discussed in detail.
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Affiliation(s)
- Yu Hashimoto
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan.
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4
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Blackstone CC, Wallace AA, Sanov A. Photoelectron angular distributions in photodetachment from polarised d-like states: the case of HO2−. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1831636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Adam A. Wallace
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, USA
| | - Andrei Sanov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, USA
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5
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Wallace AA, Dauletyarov Y, Sanov A. Deprotonation of Isoxazole: A Photoelectron Imaging Study. J Phys Chem A 2020; 124:7768-7775. [DOI: 10.1021/acs.jpca.0c06838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Adam A. Wallace
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Yerbolat Dauletyarov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Andrei Sanov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
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6
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Gregory N, Reveles JU, Bly J, Luong T. Ab Initio Molecular Dynamics Investigation of the Electronic and Structural Stability of Anionic O 2-(H 2O) n, n = 1-16 Clusters. J Phys Chem A 2019; 123:7528-7535. [PMID: 31387356 DOI: 10.1021/acs.jpca.9b04510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report an ab initio molecular dynamics investigation of the electronic and structural stability of water molecules binding to a nucleation O2- particle, O2-(H2O)n with n = 1-16, to ascertain the factors that create particularly stable species. Our results compare well with previous experimental and theoretical reports for clusters with less water content, find three new geometries for species with 7, 9, and 10 water molecules, and determine that 8, 11, 13, and 15 water molecules form remarkably stable structures around O2-. These special clusters correspond to well-defined compact structures formed by cubes and four-member rings made of water's hydrogen bonds interacting with a negative kernel formed by O2- with five water molecules, O2-(H2O)5, in which the negative charge is localized in the first four water molecules, while the fifth molecule provides geometrical stability. We assess the clusters' energetic stability based on dissociation energies, analyze electron detachment energies to understand its geometrical evolution, and investigate its charge distribution based upon isosurfaces of the highest occupied molecular orbital (HOMO). This research can help provide theoretical insight into the starting steps of nucleation of water clusters around ionic particles.
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Affiliation(s)
- N Gregory
- Maggie L. Walker Governor's School , Richmond , Virginia 23220 , United States
| | - J U Reveles
- Advanced Career Education Center at Highland Springs , Highland Springs , Virginia 23075 , United States
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7
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Manna S, Mishra S. Vibronic structure and photoelectron angular distribution in the photoelectron spectrum of ICN. J Chem Phys 2018; 149:204308. [DOI: 10.1063/1.5050461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Soumitra Manna
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
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8
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Li Y, Zou J, Xiong XG, Su J, Xie H, Fei Z, Tang Z, Liu H. Probing Chemical Bonding and Electronic Structures in ThO - by Anion Photoelectron Imaging and Theoretical Calculations. J Phys Chem A 2017; 121:2108-2113. [PMID: 28221794 DOI: 10.1021/acs.jpca.6b11554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Because of renewed research on thorium-based molten salt reactors, there is growing demand and interest in enhancing the knowledge of thorium chemistry both experimentally and theoretically. Compared with uranium, thorium has few chemical studies reported up to the present. Here we report the vibrationally resolved photoelectron imaging of the thorium monoxide anion. The electron affinity of ThO is first reported to be 0.707 ± 0.020 eV. Vibrational frequencies of the ThO molecule and its anion are determined from Franck-Condon simulation. Spectroscopic evidence is obtained for the two-electron transition in ThO-, indicating the strong electron correlation among the (7sσ)2(6dδ)1 electrons in ThO- and the (7sσ)2 electrons in ThO. These findings are explained by using quantum-chemical calculations including spin-orbit coupling, and the chemical bonding of gaseous ThO molecules is analyzed. The present work will enrich our understanding of bonding capacities with the 6d valence shell.
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Affiliation(s)
- Yanli Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
| | - Jinghan Zou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, China
| | - Xiao-Gen Xiong
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
| | - Jing Su
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
| | - Hua Xie
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, China
| | - Zejie Fei
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
| | - Zichao Tang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China
| | - Hongtao Liu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
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9
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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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10
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Liu Y, Ning C. Calculation of photodetachment cross sections and photoelectron angular distributions of negative ions using density functional theory. J Chem Phys 2016; 143:144310. [PMID: 26472382 DOI: 10.1063/1.4932978] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recently, the development of photoelectron velocity map imaging makes it much easier to obtain the photoelectron angular distributions (PADs) experimentally. However, explanations of PADs are only qualitative in most cases, and very limited works have been reported on how to calculate PAD of anions. In the present work, we report a method using the density-functional-theory Kohn-Sham orbitals to calculate the photodetachment cross sections and the anisotropy parameter β. The spherical average over all random molecular orientation is calculated analytically. A program which can handle both the Gaussian type orbital and the Slater type orbital has been coded. The testing calculations on Li(-), C(-), O(-), F(-), CH(-), OH(-), NH2 (-), O2 (-), and S2 (-) show that our method is an efficient way to calculate the photodetachment cross section and anisotropy parameter β for anions, thus promising for large systems.
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Affiliation(s)
- Yuan Liu
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Chuangang Ning
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
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11
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Dixon AR, Khuseynov D, Sanov A. Benzonitrile: Electron affinity, excited states, and anion solvation. J Chem Phys 2015; 143:134306. [DOI: 10.1063/1.4931985] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Andrew R. Dixon
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA
| | - Dmitry Khuseynov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA
| | - Andrei Sanov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA
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12
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Khuseynov D, Blackstone CC, Culberson LM, Sanov A. Photoelectron angular distributions for states of any mixed character: an experiment-friendly model for atomic, molecular, and cluster anions. J Chem Phys 2015; 141:124312. [PMID: 25273442 DOI: 10.1063/1.4896241] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a model for laboratory-frame photoelectron angular distributions in direct photodetachment from (in principle) any molecular orbital using linearly polarized light. A transparent mathematical approach is used to generalize the Cooper-Zare central-potential model to anionic states of any mixed character. In the limit of atomic-anion photodetachment, the model reproduces the Cooper-Zare formula. In the case of an initial orbital described as a superposition of s and p-type functions, the model yields the previously obtained s-p mixing formula. The formalism is further advanced using the Hanstorp approximation, whereas the relative scaling of the partial-wave cross-sections is assumed to follow the Wigner threshold law. The resulting model describes the energy dependence of photoelectron anisotropy for any atomic, molecular, or cluster anions, usually without requiring a direct calculation of the transition dipole matrix elements. As a benchmark case, we apply the p-d variant of the model to the experimental results for NO(-) photodetachment and show that the observed anisotropy trend is described well using physically meaningful values of the model parameters. Overall, the presented formalism delivers insight into the photodetachment process and affords a new quantitative strategy for analyzing the photoelectron angular distributions and characterizing mixed-character molecular orbitals using photoelectron imaging spectroscopy of negative ions.
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Affiliation(s)
- Dmitry Khuseynov
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
| | | | - Lori M Culberson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
| | - Andrei Sanov
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
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13
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Sanov A. Laboratory-Frame Photoelectron Angular Distributions in Anion Photodetachment: Insight into Electronic Structure and Intermolecular Interactions. Annu Rev Phys Chem 2014; 65:341-63. [DOI: 10.1146/annurev-physchem-040513-103656] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andrei Sanov
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721-0041;
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14
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Sanov A, Grumbling ER, Goebbert DJ, Culberson LM. Photodetachment anisotropy for mixed s-p states: 8/3 and other fractions. J Chem Phys 2013; 138:054311. [PMID: 23406123 DOI: 10.1063/1.4789811] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An approximate model for analytical prediction of photoelectron angular distributions in anion photodetachment from mixed s-p states is presented. Considering the dipole-allowed s, p, and d free-electron partial waves, the model describes photodetachment anisotropy in terms of the fractional p character of the initial orbital and the A and B coefficients describing the relative intensities of the p → d to p → s and s → p to p → s channels, respectively. The model represents an extension of the central-potential model to an intermediate regime encompassing varying degrees of s and p contributions to the initial bound orbital. This description is applicable to a broad class of hybrid molecular orbitals, particularly those localized predominantly on a single atom. Under the additional assumption of hydrogenic or Slater-type orbitals, the B/A ratio in photodetachment from a mixed 2s-2p state is shown to equal 8/3. Corresponding fractions are derived for other ns-np mixing cases. The predictions of the model are tested on several anion systems, including NH(2)(-) and CCl(2)(-). The quantitative discrepancies in the latter case are attributed to the breakdown of the central-atom approximation and a mechanism for corresponding corrections is indicated.
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Affiliation(s)
- Andrei Sanov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA.
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15
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Bandyopadhyay B, Pruitt CJM, Goebbert DJ. Communication: Photoelectron angular distributions of CH− reveal a temporary anion state. J Chem Phys 2013; 138:201101. [DOI: 10.1063/1.4808045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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16
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Culberson LM, Blackstone CC, Sanov A. Photoelectron Angular Distributions of Pyridinide: A Benchmark Application of the Mixed s–p Model to a Truly Polyatomic Anion. J Phys Chem A 2013; 117:11760-5. [DOI: 10.1021/jp402507v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lori Marie Culberson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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17
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Chiou MF, Sheu WS. Exploring water binding motifs to an excess electron via X2(-)(H2O) [X = O, F]. J Phys Chem A 2012; 116:7694-702. [PMID: 22762788 DOI: 10.1021/jp3030232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
X(2)(-)(H(2)O) [X = O, F] is utilized to explore water binding motifs to an excess electron via ab initio calculations at the MP4(SDQ)/aug-cc-pVDZ + diffs(2s2p,2s2p) level of theory. X(2)(-)(H(2)O) can be regarded as a water molecule that binds to an excess electron, the distribution of which is gauged by X(2). By varying the interatomic distance of X(2), r(X1-X2), the distribution of the excess electron is altered, and the water binding motifs to the excess electron is then examined. Depending on r(X1-X2), both binding motifs of C(s) and C(2v) forms are found with a critical distance of ∼1.37 Å and ∼1.71 Å for O(2)(-)(H(2)O) and F(2)(-)(H(2)O), respectively. The energetic and geometrical features of O(2)(-)(H(2)O) and F(2)(-)(H(2)O) are compared. In addition, various electronic properties of X(2)(-)(H(2)O) are examined. For both O(2)(-)(H(2)O) and F(2)(-)(H(2)O), the C(s) binding motif appears to prevail at a compact distribution of the excess electron. However, when the electron is diffuse, characterized by the radius of gyration in the direction of the X(2) bond axis with a threshold of ∼0.84 Å, the C(2v) binding motif is formed.
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Affiliation(s)
- Mong-Feng Chiou
- Department of Chemistry, Fu-Jen Catholic University, Xinzhuang, New Taipei City 24205, Taiwan, Republic of China
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18
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Khuseynov D, Goebbert DJ, Sanov A. Oxygen cluster anions revisited: solvent-mediated dissociation of the core O4(-) anion. J Chem Phys 2012; 136:094312. [PMID: 22401445 DOI: 10.1063/1.3691104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electronic structure and photochemistry of the O(2n)(-)(H(2)O)(m), n = 1-6, m = 0-1 cluster anions is investigated at 532 nm using photoelectron imaging and photofragment mass-spectroscopy. The results indicate that both pure oxygen clusters and their hydrated counterparts with n ≥ 2 form an O(4)(-) core. Fragmentation of these clusters yields predominantly O(2)(-) and O(2)(-)·H(2)O anionic products, with the addition of O(4)(-) fragments for larger parent clusters. The fragment autodetachment patterns observed for O(6)(-) and larger O(2n)(-) species, as well as some of their hydrated counterparts, indicate that the corresponding O(2)(-) fragments are formed in excited vibrational states (v ≥ 4). Yet, surprisingly, the unsolvated O(4)(-) anion itself does not show fragment autodetachment at 532 nm. It is hypothesized that the vibrationally excited O(2)(-) is formed in the intra-cluster photodissociation of the O(4)(-) core anion via a charge-hopping electronic relaxation mechanism mediated by asymmetric solvation of the nascent photofragments: O(4)(-) → O(2)(-)(X(2)Π(g)) + O(2)(a(1)Δ(g)) → O(2)(X(3)Σ(g)(-)) + O(2)(-)(X(2)Π(g)). This process depends on the presence of solvent molecules and leads to vibrationally excited O(2)(-)(X(2)Π(g)) products.
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Affiliation(s)
- Dmitry Khuseynov
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, USA
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Culberson LM, Sanov A. Electronic states of thiophenyl and furanyl radicals and dissociation energy of thiophene via photoelectron imaging of negative ions. J Chem Phys 2011; 134:204306. [PMID: 21639439 DOI: 10.1063/1.3593275] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report photoelectron images and spectra of deprotonated thiophene, C(4)H(3)S(-), obtained at 266, 355, and 390 nm. Photodetachment of the α isomer of the anion is observed, and the photoelectron bands are assigned to the ground X(2)A(') (σ) and excited A(2)A(") and B(2)A(") (π) states of the thiophenyl radical. The photoelectron angular distributions are consistent with photodetachment from the respective in-plane (σ) and out-of-plane (π(∗)) orbitals. The adiabatic electron affinity of α-(●)C(4)H(3)S is determined to be 2.05 ± 0.08 eV, while the B(2)A(") term energy is estimated at 1.6 ± 0.1 eV. Using the measured electron affinity and the electron affinity/acidity thermodynamic cycle, the C-H(α) bond dissociation energy of thiophene is calculated as DH(298)(H(α)-C(4)H(3)S) = 115 ± 3 kcal/mol. Comparison of this value to other, previously reported C-H bond dissociation energies, in particular for benzene and furan, sheds light of the relative thermodynamic stabilities of the corresponding radicals. In addition, the 266 nm photoelectron image and spectrum of the furanide anion, C(4)H(3)O(-), reveal a previously unobserved vibrationally resolved band, assigned to the B(2)A(") excited state of the furanyl radical, (●)C(4)H(3)O. The observed band origin corresponds to a 2.53 ± 0.01 eV B(2)A(") term energy, while the resolved vibrational progression (853 ± 42 cm(-1)) is assigned to an in-plane ring mode of α-(●)C(4)H(3)O (B(2)A(")).
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Affiliation(s)
- Lori Marie Culberson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
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Van Duzor M, Mbaiwa F, Wei J, Singh T, Mabbs R, Sanov A, Cavanagh SJ, Gibson ST, Lewis BR, Gascooke JR. Vibronic coupling in the superoxide anion: the vibrational dependence of the photoelectron angular distribution. J Chem Phys 2011; 133:174311. [PMID: 21054036 DOI: 10.1063/1.3493349] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a comprehensive photoelectron imaging study of the O(2)(X (3)Σ(g)(-),v(')=0-6)←O(2)(-)(X (2)Π(g),v(")=0) and O(2)(a (1)Δ(g),v(')=0-4)←O(2)(-)(X (2)Π(g),v(")=0) photodetachment bands at wavelengths between 900 and 455 nm, examining the effect of vibronic coupling on the photoelectron angular distribution (PAD). This work extends the v(')=1-4 data for detachment into the ground electronic state, presented in a recent communication [R. Mabbs, F. Mbaiwa, J. Wei, M. Van Duzor, S. T. Gibson, S. J. Cavanagh, and B. R. Lewis, Phys. Rev. A 82, 011401(R) (2010)]. Measured vibronic intensities are compared to Franck-Condon predictions and used as supporting evidence of vibronic coupling. The results are analyzed within the context of the one-electron, zero core contribution (ZCC) model [R. M. Stehman and S. B. Woo, Phys. Rev. A 23, 2866 (1981)]. For both bands, the photoelectron anisotropy parameter variation with electron kinetic energy, β(E), displays the characteristics of photodetachment from a d-like orbital, consistent with the π(g)(∗) 2p highest occupied molecular orbital of O(2)(-). However, differences exist between the β(E) trends for detachment into different vibrational levels of the X (3)Σ(g)(-) and a (1)Δ(g) electronic states of O(2). The ZCC model invokes vibrational channel specific "detachment orbitals" and attributes this behavior to coupling of the electronic and nuclear motion in the parent anion. The spatial extent of the model detachment orbital is dependent on the final state of O(2): the higher the neutral vibrational excitation, the larger the electron binding energy. Although vibronic coupling is ignored in most theoretical treatments of PADs in the direct photodetachment of molecular anions, the present findings clearly show that it can be important. These results represent a benchmark data set for a relatively simple system, upon which to base rigorous tests of more sophisticated models.
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Affiliation(s)
- Matthew Van Duzor
- Department of Chemistry, Washington University, One Brookings Dr., Campus Box 1134 Saint Louis, Missouri 63130, USA
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Sheu WS, Chiou MF. Potential Energy Surface of O2−(H2O) and Factors Controlling Water-to-O2− Binding Motifs. J Phys Chem A 2010; 115:99-104. [DOI: 10.1021/jp110264x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wen-Shyan Sheu
- Department of Chemistry, Fu-Jen Catholic University, Taipei, Taiwan 242, Republic of China
| | - Mong-Feng Chiou
- Department of Chemistry, Fu-Jen Catholic University, Taipei, Taiwan 242, Republic of China
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Goebbert DJ, Khuseynov D, Sanov A. Photoelectron Imaging of Cyanovinylidene and Cyanoacetylene Anions. J Phys Chem A 2010; 114:2259-65. [DOI: 10.1021/jp9106102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel J. Goebbert
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041
| | - Dmitry Khuseynov
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041
| | - Andrei Sanov
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041
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Oana CM, Krylov AI. Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals. J Chem Phys 2009; 131:124114. [DOI: 10.1063/1.3231143] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Goebbert DJ, Sanov A. Photodetachment, photofragmentation, and fragment autodetachment of [O[sub 2n](H[sub 2]O)[sub m]][sup −] clusters: Core-anion structures and fragment energy partitioning. J Chem Phys 2009. [DOI: 10.1063/1.3224135] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Velarde L, Habteyes T, Grumbling ER, Pichugin K, Sanov A. Solvent resonance effect on the anisotropy of NO−(N2O)n cluster anion photodetachment. J Chem Phys 2007; 127:084302. [PMID: 17764243 DOI: 10.1063/1.2766948] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photodetachment from NO(-)(N(2)O)(n) cluster anions (n< or =7) is investigated using photoelectron imaging at 786, 532, and 355 nm. Compared to unsolvated NO(-), the photoelectron anisotropy with respect to the laser polarization direction diminishes drastically in the presence of the N(2)O solvent, especially in the 355 nm data. In contrast, a less significant anisotropy loss is observed for NO(-)(H(2)O)(n). The effect is attributed to photoelectron scattering on the solvent, which in the N(2)O case is mediated by the (2)Pi anionic resonance. No anionic resonances exist for H(2)O in the applicable photoelectron energy range, in line with the observed difference between the photoelectron images obtained with the two solvents. The momentum-transfer cross section, rather than the total scattering cross section, is argued to be an appropriate physical parameter predicting the solvent effects on the photoelectron angular distributions in these cluster anions.
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Affiliation(s)
- Luis Velarde
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041, USA
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