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Gerlach M, Schaffner D, Preitschopf T, Karaev E, Bozek J, Holzmeier F, Fischer I. X-ray induced fragmentation of fulminic acid, HCNO. J Chem Phys 2023; 159:114306. [PMID: 37721327 DOI: 10.1063/5.0167395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/24/2023] [Indexed: 09/19/2023] Open
Abstract
The fragmentation of fulminic acid, HCNO, after excitation and ionization of core electrons was investigated using Auger-electron-photoion coincidence spectroscopy. A considerable degree of site-selectivity is observed. Ionization of the carbon and oxygen 1s electron leads to around 70% CH+ + NO+, while ionization at the central N-atom produces only 37% CH+ + NO+, but preferentially forms O+ + HCN+ and O+ + CN+. The mass-selected Auger-electron spectra show that these fragments are associated with higher binding energy final states. Furthermore, ionization of the C 1s electron leads to a higher propensity for C-H bond fission compared to O 1s ionization. Following resonant Auger-Meitner decay after 1s → 3π excitation, 12 different ionic products are formed. At the C 1s edge, the parent ion HCNO+ is significantly more stable compared to the other two edges, which we also attribute to the higher contribution of final states with low binding energies in the C 1s resonant Auger electron spectra.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Emil Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - John Bozek
- Synchrotron SOLEIL, 91192 Gif-sur-Yvette, France
| | | | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
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Schio L, Alagia M, Richter R, Zhaunerchyk V, Stranges S, Pirani F, Vecchiocattivi F, Parriani M, Falcinelli S. Double Photoionization of Nitrosyl Chloride by Synchrotron Radiation in the 24-70 eV Photon Energy Range. Molecules 2023; 28:5218. [PMID: 37446880 DOI: 10.3390/molecules28135218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/15/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
The behavior of nitrosyl chloride (ClNO) exposed to ionizing radiation was studied by direct probing valence-shell electrons in temporal coincidence with ions originating from the fragmentation process of the transient ClNO2+. Such a molecular dication was produced by double photoionization with synchrotron radiation in the 24-70 eV photon energy range. The experiment has been conducted at the Elettra Synchrotron Facility of Basovizza (Trieste, Italy) using a light beam linearly polarized with the direction of the polarization vector parallel to the ClNO molecular beam axis. ClNO molecules crossing the photon beam at right angles in the scattering region are generated by effusive expansion and randomly oriented. The threshold energy for the double ionization of ClNO (30.1 ± 0.1 eV) and six dissociation channels producing NO+/Cl+, N+/Cl+, N+/O+, O+/Cl+, ClN+/O+, NO+/Cl2+ ion pairs, with their relative abundance and threshold energies, have been measured.
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Affiliation(s)
- Luca Schio
- IOM CNR Laboratorio TASC, 34012 Trieste, Italy
| | | | - Robert Richter
- Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy
| | - Vitali Zhaunerchyk
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Stefano Stranges
- IOM CNR Laboratorio TASC, 34012 Trieste, Italy
- Department of Chemistry and Drug Technology, University of Rome Sapienza, 00185 Rome, Italy
| | - Fernando Pirani
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Franco Vecchiocattivi
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Marco Parriani
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
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Salen P, Schio L, Richter R, Alagia M, Stranges S, Falcinelli S, Zhaunerchyk V. Electronic state influence on selective bond breaking of core-excited nitrosyl chloride (ClNO). J Chem Phys 2022; 157:124306. [DOI: 10.1063/5.0106642] [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 potential for selective bond breaking of a small molecule was investigated with electron-spectroscopy and electron-ion coincidence experiments on ClNO. The electron spectra were measured upon direct valence photo-ionization and upon resonant core-excitation at the N 1s- and O 1s-edges followed by emission of resonant Auger (RA) electrons. The RA spectra were analyzed with particular emphasis on the assignment of the participator and spectator states. The latter are of special relevance for investigations of how distinct electronic configurations influence selective bond breaking. The electron-ion coincidence measurements provided branching fractions of the produced ion-fragments as a function of electron binding energy. It explicitly demonstrates the influence of the final electronic states created after the photo-ionization and RA decay, on the fragmentation. In particular, we observe a significantly different branching fraction for spectator states compared with participator states. The bonds broken for the spectator states are also found to correlate with the anti-bonding character of the spectator-electron orbital.
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Affiliation(s)
- Peter Salen
- Physics and Astronomy, Uppsala Universitet, Sweden
| | - Luca Schio
- IOM CNR Laboratorio TASC, 34012 Trieste, Italy
| | | | | | - Stefano Stranges
- Chemistry and Technologies of Drugs, University of Rome La Sapienza, Italy
| | - Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Italy
| | - Vitali Zhaunerchyk
- Department of Physics, University of Gothenburg Department of Physics, Sweden
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Gerlach M, Fantuzzi F, Wohlfart L, Kopp K, Engels B, Bozek J, Nicolas C, Mayer D, Gühr M, Holzmeier F, Fischer I. Fragmentation of isocyanic acid, HNCO, following core excitation and ionization. J Chem Phys 2021; 154:114302. [PMID: 33752348 DOI: 10.1063/5.0044506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We report a study on the fragmentation of core-ionized and core-excited isocyanic acid, HNCO, using Auger-electron/photoion coincidence spectroscopy. Site-selectivity is observed both for normal and resonant Auger electron decay. Oxygen 1s ionization leads to the CO+ + NH+ ion pairs, while nitrogen 1s ionization results in three-body dissociation and an efficient fragmentation of the H-N bond in the dication. Upon 1s → 10a' resonant excitation, clear differences between O and N sites are discernible as well. In both cases, the correlation between the dissociation channel and the binding energy of the normal Auger electrons indicates that the fragmentation pattern is governed by the excess energy available in the final ionic state. High-level multireference calculations suggest pathways to the formation of the fragment ions NO+ and HCO+, which are observed although the parent compound contains neither N-O nor H-C bonds. This work contributes to the goal to achieve and understand site-selective fragmentation upon ionization and excitation of molecules with soft x-ray radiation.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Felipe Fantuzzi
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Lilith Wohlfart
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Karina Kopp
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Bernd Engels
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - John Bozek
- Synchrotron SOLEIL, 91192 Gif-sur-Yvette, France
| | | | - Dennis Mayer
- Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam-Golm, Germany
| | - Markus Gühr
- Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam-Golm, Germany
| | - Fabian Holzmeier
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
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