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Jara-Toro RA, Taccone MI, Dezalay J, Noble JA, von Helden G, Pino GA. Observation of a core-excited dipole-bound state ∼1 eV above the electron detachment threshold in cryogenically cooled acetylacetonate. J Chem Phys 2024; 161:084305. [PMID: 39206831 DOI: 10.1063/5.0223957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 08/15/2024] [Indexed: 09/04/2024] Open
Abstract
Dipole-bound states in anions exist when a polar neutral core binds an electron in a diffuse orbital through charge-dipole interaction. Electronically excited polar neutral cores can also bind an electron in a diffuse orbital to form Core-Excited Dipole-Bound States (CE-DBSs), which are difficult to observe because they usually lie above the electron detachment threshold, leading to very short lifetimes and, thus, unstructured transitions. We report here the photodetachment spectroscopy of cryogenically cooled acetylacetonate anion (C5H7O2-) recorded by detecting the neutral radical produced upon photodetachment and the infrared spectroscopy in He-nanodroplets. Two DBSs were identified in this anion. One of them lies close to the electron detachment threshold (∼2.74 eV) and is associated with the ground state of the radical (D0-DBS). Surprisingly, the other DBS appears as resonant transitions at 3.69 eV and is assigned to the CE-DBS associated with the first excited state of the radical (D1-DBS). It is proposed that the resonant transitions of the D1-DBS are observed ∼1 eV above the detachment threshold because its lifetime is determined by the internal conversion to the D0-DBS, after which the fast electron detachment takes place.
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Affiliation(s)
- Rafael A Jara-Toro
- INFIQC: Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET - UNC) - Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
- Departamento de Fisicoquímica, Facultad de Ciencias Químicas - Universidad Nacional de Córdoba - Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
- Centro Láser de Ciencias Moleculares - Universidad Nacional de Córdoba - Haya de la Torre s/n, Pabellón Argentina, Ciudad Universitaria, X5000HUA Córdoba, Argentina
| | - Martín I Taccone
- Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Jordan Dezalay
- Physique des Interactions Ioniques et Moléculaires (PIIM): CNRS / Aix-Marseille Université UMR 7345, Avenue Escadrille Normandie-Niémen, 13013 Marseille, France
| | - Jennifer A Noble
- Physique des Interactions Ioniques et Moléculaires (PIIM): CNRS / Aix-Marseille Université UMR 7345, Avenue Escadrille Normandie-Niémen, 13013 Marseille, France
| | - Gert von Helden
- Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Gustavo A Pino
- INFIQC: Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET - UNC) - Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
- Departamento de Fisicoquímica, Facultad de Ciencias Químicas - Universidad Nacional de Córdoba - Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
- Centro Láser de Ciencias Moleculares - Universidad Nacional de Córdoba - Haya de la Torre s/n, Pabellón Argentina, Ciudad Universitaria, X5000HUA Córdoba, Argentina
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Zhang YR, Yuan DF, Wang LS. Probing Dipole-Bound States Using Photodetachment Spectroscopy and Resonant Photoelectron Imaging of Cryogenically Cooled Anions. J Phys Chem Lett 2023; 14:7368-7381. [PMID: 37565830 DOI: 10.1021/acs.jpclett.3c01994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Molecular anions with polar neutral cores can support highly diffuse dipole-bound states below their detachment thresholds due to the long-range charge-dipole interaction. Such nonvalence states constitute a special class of excited electronic states for anions and were observed in early photodetachment experiments to measure the electron affinities of organic radicals. Recent experimental advances, in particular, the ability to create cold anions using a cryogenically cooled Paul trap, have allowed the investigation of dipole-bound excited states at a new level. For the first time, the zero-point level of dipole-bound excited states can be observed via resonant two-photon detachment, and resonant photoelectron spectroscopy can be performed via the above-threshold vibrational levels (Feshbach resonances) of the dipole-bound states. This Perspective describes recent progress in the investigation of dipole-bound states in the authors' lab using an electrospray photoelectron spectroscopy apparatus equipped with a cryogenically cooled Paul trap and high-resolution photoelectron imaging.
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Affiliation(s)
- Yue-Rou Zhang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Dao-Fu Yuan
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Yuan DF, Liu Y, Zhang YR, Wang LS. Observation of a Polarization-Assisted Dipole-Bound State. J Am Chem Soc 2023; 145:5512-5522. [PMID: 36809761 DOI: 10.1021/jacs.3c00246] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The critical dipole moment to bind an electron was empirically determined to be 2.5 debye, even though smaller values were predicted theoretically. Herein, we report the first observation of a polarization-assisted dipole-bound state (DBS) for a molecule with a dipole moment below 2.5 debye. Photoelectron and photodetachment spectroscopies are conducted for cryogenically cooled indolide anions, where the neutral indolyl radical has a dipole moment of 2.4 debye. The photodetachment experiment reveals a DBS only 6 cm-1 below the detachment threshold along with sharp vibrational Feshbach resonances. Rotational profiles are observed for all of the Feshbach resonances, which are found to have surprisingly narrow linewidths and long autodetachment lifetimes attributed to weak coupling between vibrational motions and the nearly free dipole-bound electron. Calculations suggest that the observed DBS has π-symmetry stabilized by the strong anisotropic polarizability of indolyl.
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Affiliation(s)
- Dao-Fu Yuan
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Yuan Liu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yue-Rou Zhang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Sagan CR, Anstöter CS, Thodika M, Wilson KD, Matsika S, Garand E. Spectroscopy and Theoretical Modeling of Tetracene Anion Resonances. J Phys Chem Lett 2022; 13:10245-10252. [PMID: 36301005 DOI: 10.1021/acs.jpclett.2c02931] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The positions and widths of the optically allowed electronic states of the tetracene radical anion located above the detachment threshold energy (i.e anion resonances) are mapped out using total photodetachment yield spectroscopy of cryogenically cooled ions. The presence of these states is detected via the sharp increase in the photodetachment yield compared to that of the monotonic nonresonant direct photodetachment background. The resolution of the resulting spectrum is limited by the ∼5 cm-1 line width of the tunable laser and thus provides a stringent benchmark for computations of the energies and autodetachment lifetimes of these resonance states. The experimental results are compared to high-level electronic structure computations and line width modeling using the orbital stabilization method. These theoretical results are found to be in near quantitative agreement with the experimental data, highlighting their capability to accurately describe the energies and lifetimes of anion resonances for relatively large molecules.
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Affiliation(s)
- Cole R Sagan
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Cate S Anstöter
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
- Department of Chemistry, University of York, Heslington YO10 5DD, U.K
| | - Mushir Thodika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Kenneth D Wilson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Etienne Garand
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
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Marlton SJP, Trevitt A. Laser Photodissocation, Action Spectroscopy and Mass Spectrometry Unite to Detect and Separate Isomers. Chem Commun (Camb) 2022; 58:9451-9467. [DOI: 10.1039/d2cc02101c] [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
The separation and detection of isomers remains a challenge for many areas of mass spectrometry. This article highlights laser photodissociation and ion mobility strategies that have been deployed to tackle...
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Marceca E, Noble JA, Dedonder-Lardeux C, Jouvet C. Loss of CO 2 from Monodeprotonated Phthalic Acid upon Photodissociation and Dissociative Electron Detachment. J Phys Chem A 2021; 125:7406-7413. [PMID: 34415759 DOI: 10.1021/acs.jpca.1c04854] [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
The decarboxylation (CO2 loss) mechanism of cold monodeprotonated phthalic acid was studied in a photodissociation action spectrometer by quantifying mass-selected product anions and neutral particles as a function of the excitation energy. The analysis proceeded by interpreting the translational energy distribution of the generated uncharged products, and with the help of quantum calculations. In particular, this study reveals different fragmentation pathways in the deprotonated anion and in the radical generated upon electron photodetachment. Unlike the behavior found in other deprotonated aryl carboxylic acids, which do not fragment in the anion excited state, a double loss of CO2 molecules takes place in the phthalic monoanion. Moreover, at higher excitation energies the phthalic monoanion experiences decarboxylative photodetachment with a statistical distribution of product translational energies, which contrasts with the impulsive dissociation reactions characteristic of other aryl carboxylic anions.
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Affiliation(s)
- Ernesto Marceca
- INQUIMAE (CONICET-Universidad de Buenos Aires), DQIAQF (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria), 3er piso, Pab. II, 1428 Buenos Aires, Argentina
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