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Poretskiy MS, Chichinin AI, Maul C, Gericke KH. Double-arm three-dimensional ion imaging apparatus for the study of ion pair channels in resonance enhanced multiphoton ionization. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:023107. [PMID: 26931834 DOI: 10.1063/1.4936984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a novel experimental configuration for the full quantitative characterization of the multichannel resonance enhanced multiphoton ionization (REMPI) of small molecules in cases when the ion-pair dissociation channel is important. For this purpose, a double-arm time-of-flight mass spectrometer with three-dimensional (3D) ion imaging detectors at both arms is constructed. The REMPI of HCl molecules is used to examine the constructed setup. The apparatus allows us to perform simultaneous measurements of the 3D velocity vector distributions of positive (H(+), HCl(+), and Cl(+)) and negative (Cl(-)) photoions. The characterization consists of the determination of "two-photon absorption cross sections" for the process HCl(X)+2hν → HCl*, one-photon absorption cross sections for subsequent processes HCl* + hν → HCl*, and the probability of the subsequent non-adiabatic transition HCl* → HCl(B) → H(+) + Cl(-), which leads to ionic pairs. All these data should be obtained from the analysis of the dependencies of the number of ions on the laser energy. The full characterization of the laser beam and the knowledge of the ion detection probability are necessary parts of the analysis. Detailed knowledge of losses of produced ions in the mass spectrometer before detection requires understanding and characterization of such processes like electron emission from metallic grids under ion bombardment or charge transfer between positive ions and the metal surface of the grids, like Cl(+) + (grid) → Cl(-). These important phenomena from surface science are rarely discussed in the imaging literature, and here, we try to compensate for this shortcoming.
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Affiliation(s)
- M S Poretskiy
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - A I Chichinin
- Institute of Chemical Kinetics and Combustion and Novosibirsk State University, 630090 Novosibirsk, Russia
| | - C Maul
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - K-H Gericke
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, 38106 Braunschweig, Germany
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Stråhlman C, Sankari R, Kivimäki A, Richter R, Coreno M, Nyholm R. A tandem time-of-flight spectrometer for negative-ion/positive-ion coincidence measurements with soft x-ray excitation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:013109. [PMID: 26827311 DOI: 10.1063/1.4940425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a newly constructed spectrometer for negative-ion/positive-ion coincidence spectroscopy of gaseous samples. The instrument consists of two time-of-flight ion spectrometers and a magnetic momentum filter for deflection of electrons. The instrument can measure double and triple coincidences between mass-resolved negative and positive ions with high detection efficiency. First results include identification of several negative-ion/positive-ion coincidence channels following inner-shell photoexcitation of sulfur hexafluoride (SF6).
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Affiliation(s)
| | - Rami Sankari
- MAX IV Laboratory, Lund University, P.O. Box 118, 22100 Lund, Sweden
| | - Antti Kivimäki
- Consiglio Nazionale delle Ricerche-Istituto Officina dei Materiali, Laboratorio TASC, 34149 Trieste, Italy
| | - Robert Richter
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy
| | - Marcello Coreno
- Consiglio Nazionale delle Ricerche-Istituto di Struttura della Materia, 34149 Trieste, Italy
| | - Ralf Nyholm
- MAX IV Laboratory, Lund University, P.O. Box 118, 22100 Lund, Sweden
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Bodi A, Hemberger P, Gerber T, Sztáray B. A new double imaging velocity focusing coincidence experiment: i2PEPICO. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:083105. [PMID: 22938272 DOI: 10.1063/1.4742769] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The vacuum ultraviolet (VUV) beamline of the Swiss Light Source has been upgraded after two years of operation. A new, turntable-type monochromator was constructed at the Paul Scherrer Institut, which allows for fast yaw-alignment as well as quick grating change and exchange. In addition to the original imaging photoelectron photoion coincidence endstation (iPEPICO), a second, complementary double imaging setup (i(2)PEPICO) has been built. Volatile samples can be introduced at room temperature or in a molecular beam, a pyrolysis source allows for radical production, and non-volatile solids can be evaporated in a heated cell. Monochromatic VUV radiation ionizes the sample and both photoelectrons and photoions are velocity map imaged onto two fast position sensitive detectors and detected in delayed coincidence. High intensity synchrotron radiation leads to ionization rates above 10(5) s(-1). New data acquisition and processing approaches are discussed for recording coincidence processes at high rates. The setup is capable of resolving pulsed molecular beam profiles and the synchrotron time structure temporally. The latter is shown by photoelectron autocorrelation, which displays both the 1.04 MHz ring clock frequency as well as resolving the micro-pulses with a separation of 2 ns. Kinetic energy release analysis on the dissociative photoionization of CF(4) indicates a dissociation mechanism change in the Franck-Condon allowed energy range of the first ion state.
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Affiliation(s)
- Andras Bodi
- Paul Scherrer Institut, Villigen 5232, Switzerland.
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Zhou C, Mo Y. Ion-pair dissociation of N2O in the 16.25-16.41 eV: dynamics and electronic structure. J Chem Phys 2008; 129:064312. [PMID: 18715074 DOI: 10.1063/1.2965593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ion-pair dissociation dynamics of N(2)O -->(XUV) N(2)(+)(X (2)Sigma(g)(+), v) + O(-)((2)P(j)) at 16.248, 16.271, 16.389, and 16.411 eV have been studied using the velocity map imaging method and tunable XUV laser. The electronic structures of the ion-pair states have been studied by employing the ab initio quantum chemical calculation. The translational energy distributions and the angular distributions of the photofragments have been measured. The results show that about 40% of available energies are transformed into the translational energies, and the first excited vibrational states are populated most strongly for all four excitation energies. The anisotropy parameters beta are approximately 1. The ab initio calculations at the level of CASSCF6-311++g(3df) show that the equilibrium geometries of the ion-pair states are nonlinear with bond lengths R(N-N) = 1.10 A, R(N-O) = 2.15 A, and bond angle N-N-O = 103 degrees, respectively. The ion-pair states are formed by electron migration from the bonding sigma orbital of N[triple bond]N to the antibonding sigma orbital localized primarily on the O atom. Combining the experimental and theoretical results, it is concluded that the ion-pair dissociation occurs via predissociation of Rydberg states with (1)Sigma(+) symmetry, which converges to the ion-core N(2)O(+)(A (2)Sigma(+)).
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Affiliation(s)
- Chang Zhou
- Department of Physics and Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing, 100084, China
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Mitsuke K, Katayanagi H, Kafle BP, Huang C, Yagi H, Prodhan MSI, Kubozono Y. Relative partial cross sections for single, double, and triple photoionization of C60 and C70. J Phys Chem A 2007; 111:8336-43. [PMID: 17683125 DOI: 10.1021/jp0726034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Partial cross sections for the photoion formation from C(60) and C(70) were determined from the yields of singly, doubly, and triply charged ions which were measured by mass spectrometry combined with tunable synchrotron radiation at hnu = 25-120 eV. The dependence of the detection efficiencies on the mass-to-charge ratio was evaluated by using the formula proposed by Twerenbold et al. Corrections of the detection efficiency were found to be critical for obtaining accurate partial cross sections for photoionization of fullerenes. Revisions were made of the partial cross-section curves for single and double photoionization of C(60) and C(70). The curve for triple photoionization of C(70) was newly proposed. The ratios between the cross sections for double and single photoionization increase with hnu and reach saturated values of 0.78 at 85 eV for C(60) and approximately 1.3 at 100 eV for C(70). In contrast, the ratios at 120 eV between the cross sections for triple and single photoionization of C(60) and C(70) amount to 0.14 and approximately 0.38, respectively. The formation mechanism of multiply charged fullerene ions was discussed in terms of valence-electron excitation to antibonding unoccupied orbitals and/or spherical standing waves inside the cavity of a fullerene. This excitation could be followed by Spectator Auger processes and transmission of the excess electronic energy among numerous vibrational degrees of freedom.
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Affiliation(s)
- Koichiro Mitsuke
- The Institute for Molecular Science, and Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585, Japan
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Machida S, Ukai M, Kitajima M, Kameta K, Kouchi N, Hatano Y, Hayaishi T, Ito K. Dissociation Dynamics of N2O in Superexcited States As Probed by Two-Dimensional Fluorescence Spectroscopy. J Phys Chem A 1997. [DOI: 10.1021/jp9620173] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shuntaro Machida
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Masatoshi Ukai
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Masashi Kitajima
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Kosei Kameta
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Noriyuki Kouchi
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Yoshihiko Hatano
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Tatsuji Hayaishi
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
| | - Kenji Ito
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan, Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, and Photon Factory, National Laboratory for High Energy Physics, Tsukuba, Ibaraki 305, Japan
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