1
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Cederbaum LS, Kuleff AI. Stimulated Emission of Virtual Photons: Energy Transfer by Light. J Phys Chem Lett 2024:7357-7362. [PMID: 38990327 DOI: 10.1021/acs.jpclett.4c01191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
Energy-transfer processes can be viewed as being due to the emission of a virtual photon. It is demonstrated that the emission of virtual photons and thus of energy transfer is stimulated by the sheer presence of photons. We concentrate here on interatomic/intermolecular Coulombic decay (ICD) where an excited system relaxes by transferring its excess energy to a neighbor ionizing it. ICD is inactive if this excess energy is insufficiently large. However, in the presence of photons, the long-range interaction between the system and its neighbor can utilize the photon field making ICD active. The properties of this stimulated-ICD mechanism are discussed. The concept can be transferred to other scenarios. We discuss collective-ICD where two excited molecules concertedly transfer their excess energy. Also here, the presence of photons can make the process active if the sum of excess energies were insufficient to do so. Examples with typical molecules and atoms are presented to demonstrate that these stimulated processes can play a role.
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Affiliation(s)
- Lorenz S Cederbaum
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, Heidelberg D-69120, Germany
| | - Alexander I Kuleff
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, Heidelberg D-69120, Germany
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2
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Siddiki MAKA, Kumar K, Singh H, Mukherjee J, Tribedi LC, Misra D. Charge-symmetric and -asymmetric fragmentation dynamics of argon dimers in slow Ar8+-Ar2 collisions. J Chem Phys 2024; 160:224304. [PMID: 38856070 DOI: 10.1063/5.0209104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/27/2024] [Indexed: 06/11/2024] Open
Abstract
We present an experimental study of multiple-electron capture-induced fragmentation dynamics of Ar2m+ (4 ≤m≤ 7) dimer ions in 4 keV/u Ar8+-Ar2 collisions. The fragment recoil ion pairs and the charge-changing projectiles are coincidentally measured using a double coincidence technique. The branching ratios between the different charge-sharing fragmentation channels show an inherent enhancement of the asymmetric channels. The kinetic energy release (KER) distributions for the associated electron capture process show a shift in the mean KER values toward the higher side with increasing capture stabilization. The interplay between the different projectile autoionization processes sheds light on the energy depositions to the system during collisions. The Coulomb potential energy curves give a physical insight into the role of the projectile final states in the dimer fragmentation dynamics. The dimer-axis orientation-dependent cross sections for the asymmetric fragmentation channels reveal a forward-backward asymmetry that arises from the geometry of the collision system. Our findings thus give insight into the impact parameter-controlled fragmentation dynamics of multiply charged Ar2m+ dimer ions in highly charged ion-dimer slow collisions.
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Affiliation(s)
- Md Abul Kalam Azad Siddiki
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Kamal Kumar
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Harpreet Singh
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Jibak Mukherjee
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Lokesh C Tribedi
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Deepankar Misra
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
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3
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Tian X, Guo J, Gu C, Wang H, Wang D, Liao Y, Zhu S, Zhao M, Gu Z. Ergothioneine-Sodium Hyaluronate Dressing: A Promising Approach for Protecting against Radiation-Induced Skin Injury. ACS APPLIED MATERIALS & INTERFACES 2024; 16:29917-29929. [PMID: 38813785 DOI: 10.1021/acsami.4c05416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Radiotherapy commonly causes damage to healthy tissues, particularly radiation-induced skin injury (RISI) that affects a significant majority of patients undergoing radiotherapy. Effective treatments for RISI are lacking. This study focuses on the pathogenesis of RISI, which primarily involves oxidative stress. Excessive reactive oxygen species (ROS) generation during radiation induces damage to biological macromolecules, triggering oxidative stress and inflammation. To address this, ergothioneine (EGT), a natural and biocompatibile thiol compound with excellent antioxidant activity, is explored as a potential radiation-protective agent. By utilizing its specific transport and absorption in the skin tissue, as well as its efficient and stable clearance of radiation-induced "ROS storm", EGT is combined with sodium hyaluronate (NaHA) to develop a novel radiation protective dressing suitable for the skin. This EGT-NaHA dressing demonstrates an effective ability to scavenge free radicals and reduce oxidative stress in vitro and in vivo, reducing cellular apoptosis and inflammation. These results demonstrate the protective properties of EGT against RISI, with far-reaching implications for research and development in the field of radioprotection.
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Affiliation(s)
- Xinyi Tian
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junsong Guo
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
| | - Chenglu Gu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
| | - Dongmei Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - You Liao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuang Zhu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maoru Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Department of Gastrointestinal Surgery, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu 610500, Sichuan, China
| | - Zhanjun Gu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China
- Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
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4
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Bastian B, Asmussen JD, Ltaief LB, Pedersen HB, Sishodia K, De S, Krishnan SR, Medina C, Pal N, Richter R, Sisourat N, Mudrich M. Observation of Interatomic Coulombic Decay Induced by Double Excitation of Helium in Nanodroplets. PHYSICAL REVIEW LETTERS 2024; 132:233001. [PMID: 38905671 DOI: 10.1103/physrevlett.132.233001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 04/25/2024] [Indexed: 06/23/2024]
Abstract
Interatomic Coulombic decay (ICD) plays a crucial role in weakly bound complexes exposed to intense or high-energy radiation. So far, neutral or ionic atoms or molecules have been prepared in singly excited electron or hole states that can transfer energy to neighboring centers and cause ionization and radiation damage. Here we demonstrate that a doubly excited atom, despite its extremely short lifetime, can decay by ICD; evidenced by high-resolution photoelectron spectra of He nanodroplets excited to the 2s2p+ state. We find that ICD proceeds by relaxation into excited He^{*}He^{+} atom-pair states, in agreement with calculations. The ability of inducing ICD by resonant excitation far above the single-ionization threshold opens opportunities for controlling radiation damage to a high degree of element specificity and spectral selectivity.
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Affiliation(s)
- B Bastian
- Wilhelm Ostwald Institute for Physical and Theoretical Chemistry, Leipzig University, Linnéstraße 2, 04103 Leipzig, Germany
| | - J D Asmussen
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - L Ben Ltaief
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - H B Pedersen
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - K Sishodia
- Quantum Center of Excellence for Diamond and Emergent Materials and Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| | - S De
- Quantum Center of Excellence for Diamond and Emergent Materials and Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| | - S R Krishnan
- Quantum Center of Excellence for Diamond and Emergent Materials and Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| | - C Medina
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - N Pal
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - R Richter
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - N Sisourat
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, F-75005 Paris, France
| | - M Mudrich
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
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5
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Bloß D, Trinter F, Unger I, Zindel C, Honisch C, Viehmann J, Kiefer N, Marder L, Küstner-Wetekam C, Heikura E, Cederbaum LS, Björneholm O, Hergenhahn U, Ehresmann A, Hans A. X-ray radiation damage cycle of solvated inorganic ions. Nat Commun 2024; 15:4594. [PMID: 38816362 PMCID: PMC11139941 DOI: 10.1038/s41467-024-48687-2] [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: 01/16/2024] [Accepted: 05/07/2024] [Indexed: 06/01/2024] Open
Abstract
X-ray-induced damage is one of the key topics in radiation chemistry. Substantial damage is attributed to low-energy electrons and radicals emerging from direct inner-shell photoionization or produced by subsequent processes. We apply multi-electron coincidence spectroscopy to X-ray-irradiated aqueous solutions of inorganic ions to investigate the production of low-energy electrons (LEEs) in a predicted cascade of intermolecular charge- and energy-transfer processes, namely electron-transfer-mediated decay (ETMD) and interatomic/intermolecular Coulombic decay (ICD). An advanced coincidence technique allows us to identify several LEE-producing steps during the decay of 1s vacancies in solvated Mg2+ ions, which escaped observation in previous non-coincident experiments. We provide strong evidence for the predicted recovering of the ion's initial state. In natural environments the recovering of the ion's initial state is expected to cause inorganic ions to be radiation-damage hot spots, repeatedly producing destructive particles under continuous irradiation.
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Affiliation(s)
- Dana Bloß
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany.
| | - Florian Trinter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Institut für Kernphysik, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Isaak Unger
- Chemical and Biomolecular Physics, Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Christina Zindel
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Carolin Honisch
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Johannes Viehmann
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Nils Kiefer
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Lutz Marder
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Catmarna Küstner-Wetekam
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Emilia Heikura
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Lorenz S Cederbaum
- Theoretical Chemistry, Institute of Physical Chemistry, University of Heidelberg, Heidelberg, Germany
| | - Olle Björneholm
- Chemical and Biomolecular Physics, Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Uwe Hergenhahn
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - Arno Ehresmann
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany
| | - Andreas Hans
- Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Kassel, Germany.
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6
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Ferino-Pérez A, Jagau TC. Ab Initio Computation of Auger Decay in Heavy Metals: Zinc about It. J Phys Chem A 2024; 128:3957-3967. [PMID: 38742917 DOI: 10.1021/acs.jpca.4c01316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
We report the first coupled-cluster study of Auger decay in heavy metals. The zinc atom is used as a case study due to its relevance to the Auger emission properties of the 67Ga radionuclide. Coupled-cluster theory combined with complex basis functions is used to describe the transient nature of the core-ionized zinc atom. We also introduce second-order Møller-Plesset perturbation theory as an alternative method for computing partial Auger decay widths. Scalar-relativistic effects are included in our approach for computing Auger electron energies by means of the spin-free exact two-component one-electron Hamiltonian, while spin-orbit coupling is treated by means of perturbation theory. We center our attention on the K-edge Auger decay of zinc dividing the spectrum into three parts (K-LL, K-LM, and K-MM) according to the shells involved in the decay. The computed Auger spectra are in good agreement with experimental results. The most intense peak is found at an Auger electron energy of 7432 eV, which corresponds to a 1D2 final state arising from K-L2L3 transitions. Our results highlight the importance of relativistic effects for describing Auger decay in heavier nuclei. Furthermore, the effect of a first solvation shell is studied by modeling Auger decay in the hexaaqua-zinc(II) complex. We find that K-edge Auger decay is slightly enhanced by the presence of the water molecules as compared to the bare atom.
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Affiliation(s)
| | - Thomas-C Jagau
- Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium
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7
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Rana M, Ghosh A. Full Dynamical and Ab Initio Investigation of the Electron Transfer-Mediated Decay Mechanism of He + in the Presence of Heavier Alkali Dimers. J Phys Chem A 2024; 128:1973-1983. [PMID: 38447163 DOI: 10.1021/acs.jpca.3c07115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
We have studied the electron transfer-mediated decay (ETMD) process for the 1s ionized state of the He atom in the presence of a heavier alkali homonuclear dimer (Na2, K2, and Rb2) as well as heteronuclear dimer (LiNa, NaK, and KRb). In our computation, we have considered all the alkali dimers being in the singlet electronic ground state. The electron transfer from the alkali dimer to He (1s-1) leads to the emission of another electron from the alkali dimer into the continuum. We have investigated the impact of the distance of the He atom from the center of mass of the alkali dimer on the ETMD decay width. We also performed the Born-Oppenheimer molecular dynamics simulation to understand the impact of nuclear dynamics on the ETMD process.
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Affiliation(s)
- Meenakshi Rana
- Department of Chemistry, Ashoka University, Sonipat, Haryana 131029, India
| | - Aryya Ghosh
- Department of Chemistry, Ashoka University, Sonipat, Haryana 131029, India
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8
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Pihlava L, Svensson PHW, Kukk E, Kooser K, De Santis E, Tõnisoo A, Käämbre T, André T, Akiyama T, Hessenthaler L, Giehr F, Björneholm O, Caleman C, Berholts M. Shell-dependent photofragmentation dynamics of a heavy-atom-containing bifunctional nitroimidazole radiosensitizer. Phys Chem Chem Phys 2024; 26:8879-8890. [PMID: 38426309 DOI: 10.1039/d4cp00367e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Radiation therapy uses ionizing radiation to break chemical bonds in cancer cells, thereby causing DNA damage and leading to cell death. The therapeutic effectiveness can be further increased by making the tumor cells more sensitive to radiation. Here, we investigate the role of the initial halogen atom core hole on the photofragmentation dynamics of 2-bromo-5-iodo-4-nitroimidazole, a potential bifunctional radiosensitizer. Bromine and iodine atoms were included in the molecule to increase the photoionization cross-section of the radiosensitizer at higher photon energies. The fragmentation dynamics of the molecule was studied experimentally in the gas phase using photoelectron-photoion-photoion coincidence spectroscopy and computationally using Born-Oppenheimer molecular dynamics. We observed significant changes between shallow core (I 4d, Br 3d) and deep core (I 3d) ionization in fragment formation and their kinetic energies. Despite the fact, that the ions ejected after deep core ionization have higher kinetic energies, we show that in a cellular environment, the ion spread is not much larger, keeping the damage well-localized.
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Affiliation(s)
- Lassi Pihlava
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland.
| | - Pamela H W Svensson
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
| | - Edwin Kukk
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland.
| | - Kuno Kooser
- Institute of Physics, University of Tartu, W. Ostwald 1, EST-50411, Tartu, Estonia.
| | - Emiliano De Santis
- Department of Chemistry - BMC, University of Uppsala, SE-75123 Uppsala, Sweden
| | - Arvo Tõnisoo
- Institute of Physics, University of Tartu, W. Ostwald 1, EST-50411, Tartu, Estonia.
| | - Tanel Käämbre
- Institute of Physics, University of Tartu, W. Ostwald 1, EST-50411, Tartu, Estonia.
| | - Tomas André
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
| | - Tomoko Akiyama
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
| | - Lisa Hessenthaler
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
| | - Flavia Giehr
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
| | - Olle Björneholm
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
| | - Carl Caleman
- Department of Physics and Astronomy, University of Uppsala, SE-75120 Uppsala, Sweden
- Center for Free-Electron Laser Science, DESY, DE-22607 Hamburg, Germany
| | - Marta Berholts
- Institute of Physics, University of Tartu, W. Ostwald 1, EST-50411, Tartu, Estonia.
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9
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Haitjema J, Castellanos S, Lugier O, Bespalov I, Lindblad R, Timm M, Bülow C, Zamudio-Bayer V, Lau JT, von Issendorff B, Hoekstra R, Witte K, Watts B, Schlathölter T, Brouwer AM. Soft X-ray absorption and fragmentation of tin-oxo cage photoresists. Phys Chem Chem Phys 2024; 26:5986-5998. [PMID: 38293812 DOI: 10.1039/d3cp05428d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
"Tin-oxo cage" organometallic compounds are considered as photoresists for extreme ultraviolet (EUV) photolithography. To gain insight into their electronic structure and reactivity to ionizing radiation, we trapped bare gas-phase n-butyltin-oxo cage dications [(BuSn)12O14(OH)6]2+ in an ion trap and investigated their fragmentation upon soft X-ray photoabsorption by means of mass spectrometry. In complementary experiments, the tin-oxo cages with hydroxide and trifluoroacetate counter-anions were cast in thin films and studied using X-ray transmission spectroscopy. Quantum-chemical calculations were used to interpret the observed spectra. At the carbon K-edge, a distinct pre-edge absorption band can be attributed to transitions in which electrons are promoted from C1s orbitals to the lowest unoccupied molecular orbitals, which are delocalized orbitals with strong antibonding (Sn-C σ*) character. At higher energies, the most prominent resonant transitions involve C-C and C-H σ* valence states and Rydberg (3s and 3p) states. In the solid state, the onset of continuum ionization is shifted by ∼5 eV to lower energy with respect to the gas phase, due to the electrostatic effect of the counterions. The O K-edge also shows a pre-edge absorption, but it is devoid of any specific features, because there are many transitions from the different O1s orbitals to a large number of vacant orbitals. In the gas phase, formation of the parent [(BuSn)12O14(OH)6]3+ radical ion is not observed at the C K-edge nor at the O K-edge, because the loss of a butyl group from this species is very efficient. We do observe a number of triply charged photofragment ions, some of which have lost up to 5 butyl groups. Structures of these species are proposed based on quantum-chemical calculations, and pathways of formation are discussed. Our results provide insight into the electronic structure of alkyltin-oxo cages, which is a prerequisite for understanding their response to EUV photons and their performance as EUV photoresists.
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Affiliation(s)
- Jarich Haitjema
- Advanced Research Center for Nanolithography, P.O. Box 93019, 1090 BA Amsterdam, The Netherlands.
| | - Sonia Castellanos
- Advanced Research Center for Nanolithography, P.O. Box 93019, 1090 BA Amsterdam, The Netherlands.
| | - Olivier Lugier
- Advanced Research Center for Nanolithography, P.O. Box 93019, 1090 BA Amsterdam, The Netherlands.
| | - Ivan Bespalov
- Advanced Research Center for Nanolithography, P.O. Box 93019, 1090 BA Amsterdam, The Netherlands.
| | - Rebecka Lindblad
- Department of Physics, Lund University, 22100 Lund, Sweden
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Martin Timm
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Christine Bülow
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Vicente Zamudio-Bayer
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - J Tobias Lau
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Bernd von Issendorff
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Ronnie Hoekstra
- Advanced Research Center for Nanolithography, P.O. Box 93019, 1090 BA Amsterdam, The Netherlands.
- Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | | | | | - Thomas Schlathölter
- Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
- University College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG Groningen, The Netherlands
| | - Albert M Brouwer
- Advanced Research Center for Nanolithography, P.O. Box 93019, 1090 BA Amsterdam, The Netherlands.
- University of Amsterdam, van't Hoff Institute for Molecular Sciences, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
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