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Marlton SJP, Liu C, Bieske EJ. Bond dissociation energy of FeCr+ determined through threshold photodissociation in a cryogenic ion trap. J Chem Phys 2024; 160:034301. [PMID: 38226822 DOI: 10.1063/5.0188157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 12/20/2023] [Indexed: 01/17/2024] Open
Abstract
The bond dissociation energy of FeCr+ is measured using resonance enhanced photodissociation spectroscopy in a cryogenic ion trap. The onset for FeCr+ → Fe + Cr+ photodissociation occurs well above the lowest Cr+(6S, 3d5) + Fe(5D, 3d64s2) dissociation limit. In contrast, the higher energy FeCr+ → Fe+ + Cr photodissociation process exhibits an abrupt onset at the energy of the Cr(7S, 3d54s1) + Fe+(6D, 3d64s1) limit, enabling accurate dissociation energies to be extracted: D(Fe-Cr+) = 1.655 ± 0.006 eV and D(Fe+-Cr) = 2.791 ± 0.006 eV. The measured D(Fe-Cr+) bond energy is 10%-20% larger than predictions from accompanying CAM (Coulomb Attenuated Method)-B3LYP and NEVPT2 and coupled cluster singles, doubles, and perturbative triples electronic structure calculations, which give D(Fe-Cr+) = 1.48, 1.40, and 1.35 eV, respectively. The study emphasizes that an abrupt increase in the photodissociation yield at threshold requires that the molecule possesses a dense manifold of optically accessible, coupled electronic states adjacent to the dissociation asymptote. This condition is not met for the lowest Cr+(6S, 3d5) + Fe(5D, 3d64s2) dissociation limit of FeCr+ but is satisfied for the higher energy Cr(7S, 3d54s1) + Fe+(6D, 3d64s1) dissociation limit.
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Affiliation(s)
- Samuel J P Marlton
- School of Chemistry, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Melbourne, Victoria 3010, Australia
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2
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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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3
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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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4
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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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5
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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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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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Mason JL, Folluo CN, Jarrold CC. More than little fragments of matter: Electronic and molecular structures of clusters. J Chem Phys 2021; 154:200901. [DOI: 10.1063/5.0054222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jarrett L. Mason
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Carley N. Folluo
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
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8
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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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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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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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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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