1
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Colley J, Dynak NJ, Blais JRC, Duncan MA. Photodissociation Spectroscopy and Photofragment Imaging to Probe Fe +(Benzene) 1,2 Dissociation Energies. J Phys Chem A 2023; 127:2795-2804. [PMID: 36920853 PMCID: PMC10068738 DOI: 10.1021/acs.jpca.3c00735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/03/2023] [Indexed: 03/16/2023]
Abstract
Tunable laser photodissociation spectroscopy measurements and photofragment imaging experiments are employed to investigate the dissociation energy of the Fe+(benzene) ion-molecule complex. Additional spectroscopy measurements determine the dissociation energy of Fe+(benzene)2. The dissociation energies for Fe+(benzene) determined from the threshold for the appearance of the Fe+ fragment (48.4 ± 0.2 kcal/mol) and photofragment imaging (≤49.3 ± 3.2 kcal/mol) agree nicely with each other and with the value determined previously by collision-induced dissociation (49.5 ± 2.9 kcal/mol), but they are lower than the values produced by computational chemistry at the density functional theory level using different functionals recommended for transition-metal chemistry. The threshold measurement for Fe+(benzene)2 (43.0 ± 0.2 kcal/mol) likewise agrees with the value (44.7 ± 3.8 kcal/mol) from previous collision-induced dissociation measurements.
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Affiliation(s)
- Jason
E. Colley
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| | - Nathan J. Dynak
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| | - John R. C. Blais
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| | - Michael A. Duncan
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
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2
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Ito Y, Kominato M, Nakashima Y, Ohshimo K, Misaizu F. Fragment imaging in the infrared photodissociation of the Ar-tagged protonated water clusters H 3O +-Ar and H +(H 2O) 2-Ar. Phys Chem Chem Phys 2023; 25:9404-9412. [PMID: 36928842 DOI: 10.1039/d3cp00469d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Infrared photodissociation of protonated water clusters with an Ar atom, namely H3O+-Ar and H+(H2O)2-Ar, was investigated by an imaging technique for mass-selected ions, to reveal the intra- and intermolecular vibrational dynamics. The presented system has the advantage of achieving fragment ion images with the cluster size- and mode-selective photoexcitation of each OH stretching vibration. Translational energy distributions of photofragments were obtained from the images upon the excitation of the bound (νb) and free (νf) OH stretching vibrations. The energy fractions in the translational motion were compared between νbI and νfI in H3O+-Ar or between νbII and νfII in H+(H2O)2-Ar, where the labels "I" and "II" represent H3O+-Ar and H+(H2O)2-Ar, respectively. In H3O+-Ar, the νfI excitation exhibited a smaller translational energy than νbI. This result can be explained by the higher vibrational energy of νfI, which enabled it to produce bending (ν4) excited H3O+ fragments that should be favored according to the energy-gap model. In contrast to H3O+-Ar, the νbII excitation of an Ar-tagged H2O subunit and the νfII excitation of an untagged H2O subunit resulted in very similar translational energy distributions in H+(H2O)2-Ar. The similar energy fractions independent of the excited H2O subunits suggested that the νbII and νfII excited states relaxed into a common intermediate state, in which the vibrational energy was delocalized within the H2O-H+-H2O moiety. However, the translational energy distributions for H+(H2O)2-Ar did not agree with a statistical dissociation model, which implied another aspect of the process, that is, Ar dissociation via incomplete energy randomization in the whole H+(H2O)2-Ar cluster.
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Affiliation(s)
- Yuri Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Mizuhiro Kominato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Yuji Nakashima
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
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3
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Colley JE, Dynak NJ, Blais JRC, Duncan MA. Photodissociation Spectroscopy and Photofragment Imaging of the Fe +(Acetylene) Complex. J Phys Chem A 2023; 127:1244-1251. [PMID: 36701377 DOI: 10.1021/acs.jpca.2c08456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tunable laser photodissociation spectroscopy in the 700-400 nm region and photofragment imaging experiments are employed to investigate the Fe+(acetylene) ion-molecule complex. At energies above a threshold at 679 nm, continuous dissociation is detected throughout the visible wavelength region, with regions of broad structure. Comparison to the spectrum predicted by time-dependent density functional theory (TD-DFT) indicates that the complex has a quartet ground state. The dissociation threshold for Fe+(acetylene) at 679 nm provides the dissociation energy on the quartet potential energy surface. Correction for the atomic quartet-sextet spin state energy difference provides an adiabatic dissociation energy of 36.8 ± 0.2 kcal/mol. Photofragment imaging of the Fe+ photoproduct produced at 603.5 nm produces significant kinetic energy release (KER). The photon energy and the maximum value of the KER provide an upper limit on the dissociation energy of D0 ≤ 34.6 ± 3.2 kcal/mol. The dissociation energies determined from the spectroscopy and photofragment imaging experiments agree nicely with the value determined previously by collision-induced dissociation (38.0 ± 2.6 kcal/mol). However, both values are significantly lower than those produced by computational chemistry at the DFT level using different functionals recommended for transition-metal chemistry.
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Affiliation(s)
- Jason E Colley
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Nathan J Dynak
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - John R C Blais
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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4
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Lockwood SP, Metz RB. Photofragment imaging differentiates between one- and two-photon dissociation pathways in MgI . J Chem Phys 2023; 158:054303. [PMID: 36754811 DOI: 10.1063/5.0134668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The bond strength and photodissociation dynamics of MgI+ are determined by a combination of theory, photodissociation spectroscopy, and photofragment velocity map imaging. From 17 000 to 21 500 cm-1, the photodissociation spectrum of MgI+ is broad and unstructured; photofragment images in this region show perpendicular anisotropy, which is consistent with absorption to the repulsive wall of the (1) Ω = 1 or (2) Ω = 1 states followed by direct dissociation to ground state products Mg+ (2S) + I (2P3/2). Analysis of photofragment images taken at photon energies near the threshold gives a bond dissociation energy D0(Mg+-I) = 203.0 ± 1.8 kJ/mol (2.10 ± 0.02 eV; 17 000 ± 150 cm-1). At photon energies of 33 000-41 000 cm-1, exclusively I+ fragments are formed. Over most of this region, the formation of I+ is not energetically allowed via one-photon absorption from the ground state of MgI+. Images show the observed product is due to resonance enhanced two-photon dissociation. The photodissociation spectrum from 33 000 to 38 500 cm-1 shows vibrational structure, giving an average excited state vibrational spacing of 227 cm-1. This is consistent with absorption to the (3) Ω = 0+ state from ν = 0, 1 of the (1) Ω = 0+ ground state; from the (3) Ω = 0+ state, absorption of a second photon results in dissociation to Mg* (3P° J) + I+ (3PJ). From 38 500 to 41 000 cm-1, the spectrum is broad and unstructured. We attribute this region of the spectrum to one-photon dissociation of vibrationally hot MgI+ at low energy and ground state MgI+ at higher energy to form Mg (1S) + I+ (3PJ) products.
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Affiliation(s)
- Schuyler P Lockwood
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01002, USA
| | - Ricardo B Metz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01002, USA
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5
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Tureček F. UV-vis spectroscopy of gas-phase ions. MASS SPECTROMETRY REVIEWS 2023; 42:206-226. [PMID: 34392556 DOI: 10.1002/mas.21726] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Photodissociation action spectroscopy has made a great progress in expanding investigations of gas-phase ion structures. This review deals with aspects of gas-phase ion electronic excitations that result in wavelength-dependent dissociation and light emission via fluorescence, chiefly covering the ultraviolet and visible regions of the spectrum. The principles are briefly outlined and a few examples of instrumentation are presented. The main thrust of the review is to collect and selectively present applications of UV-vis action spectroscopy to studies of stable gas-phase ion structures and combinations of spectroscopy with ion mobility, collision-induced dissociation, and ion-ion reactions leading to the generation of reactive intermediates and electronic energy transfer.
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Affiliation(s)
- František Tureček
- Department of Chemistry, University of Washington, Seattle, Washington, USA
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6
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Ito Y, Nakashima Y, Okutsu K, Nakano M, Misaizu F. Ultraviolet photodissociation of Mg +-NO complex: Ion imaging of a reaction branching in the excited states. J Chem Phys 2022; 157:124304. [PMID: 36182426 DOI: 10.1063/5.0104744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ultraviolet photodissociation processes of gas phase Mg+-NO complex were studied by photofragment ion imaging experiments and theoretical calculations for excited electronic states. At 355 nm excitation, both Mg+ and NO+ photofragment ions were observed with positive anisotropy parameters, and theoretical calculations revealed that the two dissociation channels originate from an electronic transition from a bonding orbital consisting of Mg+ 3s and NO π* orbitals to an antibonding counterpart. For the NO+ channel, the photofragment image exhibited a high anisotropy (β = 1.53 ± 0.07), and a relatively large fraction (∼40%) of the available energy was partitioned into translational energy. These observations are rationalized by proposing a rapid dissociation process on a repulsive potential energy surface correlated to the Mg(1S) + NO+(1Σ) dissociation limit. In contrast, for the Mg+ channel, the angular distribution was more isotropic (β = 0.48 ± 0.03) and only ∼25% of the available energy was released into translational energy. The differences in the recoil distribution for these competing channels imply a reaction branching on the excited state surface. On the theoretical potential surface of the excited state, we found a deep well facilitating an isomerization from bent geometry in the Franck-Condon region to linear and/or T-shaped isomer. As a result, the Mg+ fragment was formed via the structural change followed by further relaxation to lower electronic states correlated to the Mg+(2S) + NO(2Π) exit channel.
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Affiliation(s)
- Yuri Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Yuji Nakashima
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Kenichi Okutsu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Motoyoshi Nakano
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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7
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Rittgers BM, Marks J, Kellar DJ, Duncan MA. Photoinduced Charge Transfer in the Zn-Methanol Cation Studied with Selected-Ion Photofragment Imaging. J Chem Phys 2022; 157:114302. [DOI: 10.1063/5.0108467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Zn+(methanol) ion molecule complex produced by laser vaporization is studied with photofragment imaging at 280 and 266 nm. Photodissociation produces the methanol cation CH3OH+ via excitation of a charge-transfer excited state. Surprisingly, excitation of bound excited states produces the same fragment via a curve crossing prior to separation of products. Significant kinetic energy release is detected at both wavelengths with isotropic angular distributions. Similar experiments are conducted on the perdeuterated methanol complex. The Zn+ cation is a minor product channel that also exhibits significant kinetic energy release. An energetic cycle using the ionization potentials of zinc and methanol together with the kinetic energy release produces an upper limit on the Zn+-methanol bond energy of 33.7 {plus minus} 4.2 kcal/mol (1.46 {plus minus} 0.18 eV).
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Affiliation(s)
| | | | | | - Michael A. Duncan
- Department of Chemistry, University of Georgia, United States of America
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8
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Lockwood SP, Chunga T, Metz RB. Bonding, Thermodynamics, and Dissociation Dynamics of NiO + and NiS + Determined by Photofragment Imaging and Theory. J Phys Chem A 2021; 125:7425-7436. [PMID: 34427080 DOI: 10.1021/acs.jpca.1c05405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We use photofragment ion imaging and ab initio calculations to determine the bond strength and photodissociation dynamics of the nickel oxide (NiO+) and nickel sulfide (NiS+) cations. NiO+ photodissociates broadly from 20350 to 32000 cm-1, forming ground state products Ni+(2D) + O(3P) below ∼29000 cm-1. Above this energy, Ni+(4F) + O(3P) products become accessible and dominate over the ground state channel. In certain images, product spin-orbit levels are resolved, and spin-orbit propensities are determined. Image anisotropy and the results of MRCI calculations suggest NiO+ photodissociates via a 3 4Σ- ← X 4Σ- transition above the Ni+(4F) threshold and via 3 4Σ-, 2 4Σ-, and/or 2 4Π and 3 4Π excited states below the 4F threshold. The photodissociation spectrum of NiS+ from 19900 to 23200 cm-1 is highly structured, with ∼12 distinct vibronic peaks, each containing underlying substructure. Above 21600 cm-1, the Ni+(2D5/2) + S(3P) and Ni+(2D3/2) + S(3P) product spin-orbit channels compete, with a branching ratio of ∼2:1. At lower energy, Ni+(2D5/2) is formed exclusively, and S(3P2) and S(3P1) spin-orbit channels are resolved. MRCI calculations predict the ground state of NiS+ to be one of two nearly degenerate states, the 1 4Σ- and 1 4Δ. Based on images and spectra, the ground state of NiS+ is assigned as 4Δ7/2, with the 1 4Σ3/2- and 1 4Σ1/2- states 81 ± 30 and 166 ± 50 cm-1 higher in energy, respectively. The majority of the photodissociation spectrum is assigned to transitions from the 1 4Δ state to two overlapping, predissociative excited 4Δ states. Our D0 measurements for NiO+ (D0 = 244.6 ± 2.4 kJ/mol) and NiS+ (D0 = 240.3 ± 1.4 kJ/mol) are more precise and closer to each other than previously reported values. Finally, using a recent measurement of D0(NiS), we derive a more precise value for IE (NiS): 8.80 ± 0.02 eV (849 ± 1.7 kJ/mol).
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Affiliation(s)
- Schuyler P Lockwood
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Tala Chunga
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Ricardo B Metz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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9
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Nakashima Y, Ito Y, Kominato M, Ohshimo K, Misaizu F. Photofragment ion imaging in vibrational predissociation of the H 2O +Ar complex ion. J Chem Phys 2021; 154:174301. [PMID: 34241084 DOI: 10.1063/5.0049609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Vibrational predissociation processes of the H2O+Ar complex ion following mid-infrared excitations of the OH stretching modes and bending overtone of the H2O+ unit were studied by photofragment ion imaging. The anisotropy parameters, β, of the angular distributions of the photofragment ions were clearly dependent on the type (branch) of rotational excitation, β > 0 for the P-branch excitations, while β < 0 for the Q-branch excitations, which were consistent with the previous theoretical predictions for the rotationally resolved optical transition of a prolate symmetric top. The translational energy distributions had a similar form, irrespective of the excitation modes. This result suggests that the prepared excited states underwent a common relaxation pathway via the bending or bending overtone state of the H2O+ unit. In addition, the available energy was preferentially distributed into the rotational energy of the H2O+ fragment ions rather than the translational energy. The mechanism of the rotational excitations of the H2O+ fragment ions was discussed based on the steric configuration of the H2O+ and Ar units at the moment of dissociation.
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Affiliation(s)
- Yuji Nakashima
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Yuri Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Mizuhiro Kominato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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10
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Hua ZF, Zhao YX, Li YQ, Hu GM, Chen Y, Zhao DF. Ion-neutral photofragment coincidence imaging of photodissociation dynamics of ionic species. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2007119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Ze-feng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yun-xiao Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - You-qing Li
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gao-ming Hu
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dong-feng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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11
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Fournier M, Lopez GV, Spiliotis AK, Casey TA, Rakitzis TP, Chandler DW. Alignment and dissociation of electronically excited molecular hydrogen with intense laser fields. Mol Phys 2021. [DOI: 10.1080/00268976.2020.1778200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Martin Fournier
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - Gary V. Lopez
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - Alexandros K. Spiliotis
- Department of Physics, Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, University of Crete, Crete, Greece
| | - Tiernan A. Casey
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - T. Peter Rakitzis
- Department of Physics, Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, University of Crete, Crete, Greece
| | - David W. Chandler
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
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12
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Igosawa R, Hirota A, Kimura N, Kuma S, Chartkunchand KC, Mishra PM, Lindley M, Yamaguchi T, Nakano Y, Azuma T. Photodissociation spectroscopy of N 2O + in the ion storage ring RICE. J Chem Phys 2020; 153:184305. [DOI: 10.1063/5.0027805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- R. Igosawa
- Department of Physics, Saitama University, Saitama 338-8570, Japan
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - A. Hirota
- Department of Physics, Saitama University, Saitama 338-8570, Japan
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - N. Kimura
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - S. Kuma
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - K. C. Chartkunchand
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - P. M. Mishra
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - M. Lindley
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
- Department of Materials and Life Sciences, Sophia University, Tokyo 102-8554, Japan
| | - T. Yamaguchi
- Department of Physics, Saitama University, Saitama 338-8570, Japan
| | - Y. Nakano
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
- Department of Physics, Rikkyo University, Tokyo 171-8501, Japan
| | - T. Azuma
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
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13
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Rittgers BM, Leicht D, Duncan MA. Cation-π Complexes of Silver Studied with Photodissociation and Velocity-Map Imaging. J Phys Chem A 2020; 124:9166-9176. [PMID: 33103909 DOI: 10.1021/acs.jpca.0c08498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ag+(aromatic) ion-molecule complexes of benzene, toluene, or furan are generated in the gas phase by laser vaporization in a supersonic expansion. These ions are mass selected in a time-of-flight spectrometer and studied with ultraviolet laser photodissociation and photofragment imaging. UV laser excitation results in dissociative charge transfer (DCT) for these ions, producing neutral silver atom and the respective aromatic cation as the photofragments. Velocity-map imaging and slice imaging techniques are employed to investigate the kinetic energy release in these photodissociation processes. In each case, DCT produces significant kinetic energy, and evidence is also found for excitation of the internal rovibrational degrees of freedom for the molecular cations. Analysis of the kinetic energy release together with the known ionization energies of silver and the molecular ligands provides new information on the cation-π bond energies.
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Affiliation(s)
- Brandon M Rittgers
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Daniel Leicht
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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14
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Nakashima Y, Ito Y, Okutsu K, Nakano M, Misaizu F. Photodissociation processes of a water–oxygen complex cation studied by an ion imaging technique. Phys Chem Chem Phys 2020; 22:16926-16933. [DOI: 10.1039/d0cp03132a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Photodissociation dynamics of O2+–H2O in the visible and ultraviolet regions was studied by ion imaging experiments and theoretical calculations.
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Affiliation(s)
- Yuji Nakashima
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980–8578
- Japan
| | - Yuri Ito
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980–8578
- Japan
| | - Kenichi Okutsu
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980–8578
- Japan
| | - Motoyoshi Nakano
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980–8578
- Japan
| | - Fuminori Misaizu
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980–8578
- Japan
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15
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Visible photodissociation study of NO dimer cation using ion imaging technique combined with theoretical calculations. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2019.137022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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16
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Zhu GZ, Wang LS. High-resolution photoelectron imaging and resonant photoelectron spectroscopy via noncovalently bound excited states of cryogenically cooled anions. Chem Sci 2019; 10:9409-9423. [PMID: 32055317 PMCID: PMC6984392 DOI: 10.1039/c9sc03861b] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 09/16/2019] [Indexed: 01/12/2023] Open
Abstract
Valence-bound anions with polar neutral cores (μ > ∼2.5 D) can support dipole-bound excited states below the detachment threshold. These dipole-bound states (DBSs) are highly diffuse and the weakly bound electron in the DBS can be readily autodetached via vibronic coupling. Excited DBSs can be observed in photodetachment spectroscopy using a tunable laser. Tuning the detachment laser to above-threshold vibrational resonances yields vibrationally enhanced resonant photoelectron spectra, which are highly non-Franck-Condon with much richer vibrational information. This perspective describes recent advances in the studies of excited DBSs of cryogenically cooled anions using high-resolution photoelectron imaging (PEI) and resonant photoelectron spectroscopy (rPES). The basic features of dipole-bound excited states and highly non-Franck-Condon resonant photoelectron spectra will be discussed. The power of rPES to yield rich vibrational information beyond conventional PES will be highlighted, especially for low-frequency and Franck-Condon-inactive vibrational modes, which are otherwise not accessible from non-resonant conventional PES. Mode-selectivity and intra-molecular rescattering have been observed during the vibrationally induced autodetachment. Conformer-specific rPES is possible due to the different dipole-bound excited states of molecular conformers with polar neutral cores. For molecules with μ ≪ 2.5 D or without dipole moments, but large quadrupole moments, excited quadrupole-bound states can exist, which can also be used to conduct rPES.
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Affiliation(s)
- Guo-Zhu Zhu
- Department of Chemistry , Brown University , Providence , RI 02912 , USA .
| | - Lai-Sheng Wang
- Department of Chemistry , Brown University , Providence , RI 02912 , USA .
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Nakashima Y, Okutsu K, Fujimoto K, Ito Y, Kanno M, Nakano M, Ohshimo K, Kono H, Misaizu F. Visible photodissociation of the CO 2 dimer cation: fast and slow dissociation dynamics in the excited state. Phys Chem Chem Phys 2019; 21:3083-3091. [PMID: 30672937 DOI: 10.1039/c8cp07068g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Velocity and angular distributions of photofragment CO2+ ions produced from mass-selected (CO2)2+ at 532 nm excitation were observed in an ion imaging experiment. The velocity distribution was assigned to two components, fast and slow velocity components, which was consistent with the previous study by Bowers et al. The anisotropy parameters of the angular distributions for the fast and slow velocity components were experimentally determined to be βfast = 1.52 ± 0.14 and βslow = 0.46 ± 0.10, respectively. In the theoretical approach, potential energy surfaces (PESs) of (CO2)2+ were calculated along two coordinates, the intermolecular distance and mutual orientations of the CO2 monomers. In addition, molecular dynamics simulations were performed. The visible transition of the most stable staggered structure of (CO2)2+ was attributed to C[combining tilde]2Ag ← X[combining tilde]2Bu by an excited state calculation. On the PES of the C[combining tilde] state, a potential well was found in which the two CO2 monomers lay side by side to each other, in addition to a repulsive slope along the intermolecular distance. The results of the simulations confirmed that the fragment CO2+ ions with fast velocity and large anisotropy originated from the rapid dissociation of (CO2)2+ on the repulsive slope. Meanwhile, the fragment CO2+ ions with slow velocity and small anisotropy were expected to emerge from statistical dissociation after large amplitude libration of CO2 molecules which was caused by the potential well in the excited state PES.
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Affiliation(s)
- Yuji Nakashima
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
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18
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Hua Z, Feng S, Zhou Z, Liang H, Chen Y, Zhao D. A cryogenic cylindrical ion trap velocity map imaging spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:013101. [PMID: 30709209 DOI: 10.1063/1.5079264] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/15/2018] [Indexed: 06/09/2023]
Abstract
A cryogenic cylindrical ion trap velocity map imaging spectrometer has been developed to study photodissociation spectroscopy and dynamics of gaseous molecular ions and ionic complexes. A cylindrical ion trap made of oxygen-free copper is cryogenically cooled down to ∼7 K by using a closed cycle helium refrigerator and is coupled to a velocity map imaging (VMI) spectrometer. The cold trap is used to cool down the internal temperature of mass selected ions and to reduce the velocity spread of ions after extraction from the trap. For CO2 + ions, a rotational temperature of ∼12 K is estimated from the recorded [1 + 1] two-photon dissociation spectrum, and populations in spin-orbit excited X2Πg,1/2 and vibrationally excited states of CO2 + are found to be non-detectable, indicating an efficient internal cooling of the trapped ions. Based on the time-of-flight peak profile and the image of N3 +, the velocity spread of the ions extracted from the trap, both radially and axially, is interpreted as approximately ±25 m/s. An experimental image of fragmented Ar+ from 307 nm photodissociation of Ar2 + shows that, benefitting from the well-confined velocity spread of the cold Ar2 + ions, a VMI resolution of Δv/v ∼ 2.2% has been obtained. The current instrument resolution is mainly limited by the residual radial speed spread of the parent ions after extraction from the trap.
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Affiliation(s)
- Zefeng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Shaowen Feng
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Zhengfang Zhou
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Hao Liang
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Dongfeng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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19
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Suits AG. Invited Review Article: Photofragment imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:111101. [PMID: 30501356 DOI: 10.1063/1.5045325] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/25/2018] [Indexed: 06/09/2023]
Abstract
Photodissociation studies in molecular beams that employ position-sensitive particle detection to map product recoil velocities emerged thirty years ago and continue to evolve with new laser and detector technologies. These powerful methods allow application of tunable laser detection of single product quantum states, simultaneous measurement of velocity and angular momentum polarization, measurement of joint product state distributions for the detected and undetected products, coincident detection of multiple product channels, and application to radicals and ions as well as closed-shell molecules. These studies have permitted deep investigation of photochemical dynamics for a broad range of systems, revealed new reaction mechanisms, and addressed problems of practical importance in atmospheric, combustion, and interstellar chemistry. This review presents an historical overview, a detailed technical account of the range of methods employed, and selected experimental highlights illustrating the capabilities of the method.
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Affiliation(s)
- Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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20
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Johnston MD, Gentry MR, Metz RB. Photofragment Imaging, Spectroscopy, and Theory of MnO . J Phys Chem A 2018; 122:8047-8053. [PMID: 30226771 DOI: 10.1021/acs.jpca.8b07849] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional and ab initio calculations, along with photodissociation spectroscopy and ion imaging of MnO+ from 21,300 to 33,900 cm-1, are used to probe the photodissociation dynamics and bond strength of the manganese oxide cation (MnO+). These studies confirm the theoretical ground state (5Π) and determine the spin-orbit constant ( A' = 14 cm-1) of the dominant optically accessible excited state (5Π) in the region. Photodissociation via this excited 5Π state results in ground state Mn+ (7S) + O (3P) products. At energies above 30,000 cm-1, the Mn+ (5S) + O (3P) channel is energetically accessible and becomes the preferred dissociation pathway. The bond dissociation energy ( D0 = 242 ± 5 kJ/mol) of MnO+ is measured from several images of each photofragmentation channel and compared to theory, resolving a disagreement in previous measurements. MRCI+Q calculations are much more successful in predicting the observed spectrum than TD-DFT or EOM-CCSD calculations.
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Affiliation(s)
- M David Johnston
- Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Matthew R Gentry
- Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Ricardo B Metz
- Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
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21
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Johnston MD, Lockwood SP, Metz RB. Photofragment imaging and electronic spectroscopy of Al2+. J Chem Phys 2018; 148:214308. [DOI: 10.1063/1.5034353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. David Johnston
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - Schuyler P. Lockwood
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - Ricardo B. Metz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
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Okutsu K, Yamazaki K, Nakano M, Ohshimo K, Misaizu F. Ion Imaging of MgI + Photofragment in Ultraviolet Photodissociation of Mass-Selected Mg +ICH 3 Complex. J Phys Chem A 2018; 122:4948-4953. [DOI: 10.1021/acs.jpca.8b01944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kenichi Okutsu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Kenichiro Yamazaki
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Motoyoshi Nakano
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
- Institute for Excellence in Higher Education, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai 980-8576, Japan
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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