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Lyshchuk H, Chaudhary A, Luxford TFM, Ranković M, Kočišek J, Fedor J, McElwee-White L, Nag P. Electron-induced ligand loss from iron tetracarbonyl methyl acrylate. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:797-807. [PMID: 38979527 PMCID: PMC11228821 DOI: 10.3762/bjnano.15.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/18/2024] [Indexed: 07/10/2024]
Abstract
We probe the separation of ligands from iron tetracarbonyl methyl acrylate (Fe(CO)4(C4H6O2) or Fe(CO)4MA) induced by the interaction with free electrons. The motivation comes from the possible use of this molecule as a nanofabrication precursor and from the corresponding need to understand its elementary reactions fundamental to the electron-induced deposition. We utilize two complementary electron collision setups and support the interpretation of data by quantum chemical calculations. This way, both the dissociative ionization and dissociative electron attachment fragmentation channels are characterized. Considerable differences in the degree of precursor fragmentation in these two channels are observed. Interesting differences also appear when this precursor is compared to structurally similar iron pentacarbonyl. The present findings shed light on the recent electron-induced chemistry of Fe(CO)4MA on a surface under ultrahigh vacuum.
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Affiliation(s)
- Hlib Lyshchuk
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Atul Chaudhary
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Thomas F M Luxford
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Miloš Ranković
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Lisa McElwee-White
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Pamir Nag
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
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2
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Boeckers H, Chaudhary A, Martinović P, Walker AV, McElwee-White L, Swiderek P. Electron-induced deposition using Fe(CO) 4MA and Fe(CO) 5 - effect of MA ligand and process conditions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:500-516. [PMID: 38745584 PMCID: PMC11092064 DOI: 10.3762/bjnano.15.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024]
Abstract
The electron-induced decomposition of Fe(CO)4MA (MA = methyl acrylate), which is a potential new precursor for focused electron beam-induced deposition (FEBID), was investigated by surface science experiments under UHV conditions. Auger electron spectroscopy was used to monitor deposit formation. The comparison between Fe(CO)4MA and Fe(CO)5 revealed the effect of the modified ligand architecture on the deposit formation in electron irradiation experiments that mimic FEBID and cryo-FEBID processes. Electron-stimulated desorption and post-irradiation thermal desorption spectrometry were used to obtain insight into the fate of the ligands upon electron irradiation. As a key finding, the deposits obtained from Fe(CO)4MA and Fe(CO)5 were surprisingly similar, and the relative amount of carbon in deposits prepared from Fe(CO)4MA was considerably less than the amount of carbon in the MA ligand. This demonstrates that electron irradiation efficiently cleaves the neutral MA ligand from the precursor. In addition to deposit formation by electron irradiation, the thermal decomposition of Fe(CO)4MA and Fe(CO)5 on an Fe seed layer prepared by EBID was compared. While Fe(CO)5 sustains autocatalytic growth of the deposit, the MA ligand hinders the thermal decomposition in the case of Fe(CO)4MA. The heteroleptic precursor Fe(CO)4MA, thus, offers the possibility to suppress contributions of thermal reactions, which can compromise control over the deposit shape and size in FEBID processes.
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Affiliation(s)
- Hannah Boeckers
- Institute for Applied and Physical Chemistry (IAPC), Faculty 2 (Chemistry/Biology), University of Bremen, Leobener Str. 5, 28359 Bremen, Germany
| | - Atul Chaudhary
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Petra Martinović
- Institute for Applied and Physical Chemistry (IAPC), Faculty 2 (Chemistry/Biology), University of Bremen, Leobener Str. 5, 28359 Bremen, Germany
| | - Amy V Walker
- Department of Materials Science and Engineering RL10, University of Texas at Dallas, 800 W. Campbell Rd, Richardson, Texas 75080, United States
| | - Lisa McElwee-White
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Petra Swiderek
- Institute for Applied and Physical Chemistry (IAPC), Faculty 2 (Chemistry/Biology), University of Bremen, Leobener Str. 5, 28359 Bremen, Germany
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3
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Ćosićová M, Dvořák J, Čížek M. Solving Vibronic Dynamics in Electron Continuum. J Chem Theory Comput 2024; 20:2696-2710. [PMID: 38323899 PMCID: PMC11008110 DOI: 10.1021/acs.jctc.3c01217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 02/08/2024]
Abstract
We present a general two-dimensional model of conical intersection between metastable states that are vibronically coupled not only directly but also indirectly through a virtual electron in the autodetachment continuum. This model is used as a test ground for the design and comparison of iterative solvers for resonance dynamics in low-energy electron-molecule collisions. Two Krylov-subspace methods with various preconditioning schemes are compared. To demonstrate the applicability of the proposed methods on even larger models, we also test the performance of one of the methods on a recent model of vibrational excitation of CO2 by electron impact based on three vibronically coupled discrete states in continuum (Renner-Teller doublet of shape resonances coupled to a sigma virtual state) including four vibrational degrees of freedom. Two-dimensional electron energy-loss spectra resulting from electron-molecule scattering within the models are briefly discussed.
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Affiliation(s)
| | | | - Martin Čížek
- Faculty of Mathematics and
Physics, Institute of Theoretical Physics, Charles University, V Holešovičkách 2, 180 00 Prague, Czech
Republic
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4
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Sedmidubská B, Kočišek J. Interaction of low-energy electrons with radiosensitizers. Phys Chem Chem Phys 2024; 26:9112-9136. [PMID: 38376461 DOI: 10.1039/d3cp06003a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
We provide an experimentalist's perspective on the present state-of-the-art in the studies of low-energy electron interactions with common radiosensitizers, including compounds used in combined chemo-radiation therapy and their model systems. Low-energy electrons are important secondary species formed during the interaction of ionizing radiation with matter. Their role in the radiation chemistry of living organisms has become an important topic for more than 20 years. With the increasing number of works and reviews in the field, we would like to focus here on a very narrow area of compounds that have been shown to have radio-sensitizing properties on the one hand, and high reactivity towards low-energy electrons on the other hand. Gas phase experiments studying electron attachment to isolated molecules and environmental effects on reaction dynamics are reviewed for modified DNA components, nitroimidazoles, and organometallics. In the end, we provide a perspective on the future directions that may be important for transferring the fundamental knowledge about the processes induced by low-energy electrons into practice in the field of rational design of agents for concomitant chemo-radiation therapy.
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Affiliation(s)
- Barbora Sedmidubská
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, 182223 Prague, Czech Republic.
- Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 11519 Prague, Czech Republic
- Institut de Chimie Physique, UMR 8000 CNRS and Faculté des sciences d'Orsay, Université Paris Saclay, F-91405 Orsay Cedex, France
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, 182223 Prague, Czech Republic.
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5
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Mészáros D, Matejčík Š, Papp P. Formation of negative ions from cobalt tricarbonyl nitrosyl Co(CO) 3NO clusters. Phys Chem Chem Phys 2024; 26:7522-7533. [PMID: 38357994 DOI: 10.1039/d3cp05601e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Electron attachment and corresponding dissociative electron attachment (DEA) to cobalt tricarbonyl nitrosyl (Co(CO)3NO) clusters have been studied by co-expansion with Ar gas into a high vacuum. A monochromatic electron beam was utilized to generate negative ions and the resulting reaction products were identified using mass spectrometry. The ion fragments corresponding to Co(CO)3NO monomers closely resemble results from earlier gas phase experiments and studies conducted on Co(CO)3NO in He nanodroplets. However, contrary to the gas phase or He nanodroplet ion yields, a resonance structure comprising several peaks at energies above ∼4 eV was observed both in the case of molecular clusters [Co(CO)3NO]n- (with n = 1, 2, 3) and clusters comprising DEA fragments. Additionally, the ion yields of numerous other clusters such as ions without nitrosyl ([Co(CO)4]-, [Co2(CO)5]-), clusters consisting of two fragments such as ([Co2(CO)NO]-, [Co2(CO)(NO)2]-, [Co2(CO)2NO]-, [Co2(CO)2(NO)2]-, [Co3(CO)(NO)3]-, [Co3(CO)8(NO)3]-, [Co3(CO)(NO)2]-, [Co3(CO)3(NO)2]-, and [Co3(CO)5(NO)2]-) were recorded. Moreover, NO bond dissociation was confirmed with the [Co(CO)2N]-ion and with N- or O-retaining cluster ions, such as [Co2(CO)(NO)N]-, [Co2(CO)2(NO)N]-, [Co3(CO)2(NO)N]-, [Co3(CO)3(NO)N]- and [Co3(CO)(NO)2N]-, or [Co2(CO)2O]-, [Co2(CO)3O]-, [Co3(CO)3O]-, [Co3(CO)4O]-and [Co3(CO)2(NO)O]- respectively.
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Affiliation(s)
- Dušan Mészáros
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F2, 842 48 Bratislava, Slovakia.
| | - Štefan Matejčík
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F2, 842 48 Bratislava, Slovakia.
| | - Peter Papp
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F2, 842 48 Bratislava, Slovakia.
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6
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Moorby RE, Parravicini V, Alessio M, Jagau TC. Signatures of s-wave scattering in bound electronic states. Phys Chem Chem Phys 2024; 26:6532-6539. [PMID: 38323476 DOI: 10.1039/d4cp00181h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
We compute EOM-EA-CCSD and EOM-EA-CCSDT potential energy curves and one-electron properties of several anions at bond lengths close to where these states become unbound. We compare the anions of HCl and pyrrole, which are associated with s-wave scattering, with N2 and H2, which correspond to resonances. For HCl and pyrrole, we observe, on inclusion of diffuse basis functions, a pronounced bending effect in the anionic potential energy curves near the crossing points with their corresponding neutral molecules. Additionally, we observe that the Dyson orbital and second moment of the electron density become extremely large in this region; for HCl, the size of the latter becomes 5 orders of magnitude larger over a range of 5 pm. This behaviour is not observed in H2 or N2. Our work thus shows that bound state electronic-structure methods can distinguish between anions that turn into electronic resonances and those associated with s-wave scattering states.
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Affiliation(s)
- Robin E Moorby
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
- Department of Chemistry, University of Durham, South Road, Durham, DH1 3LE, UK
| | | | - Maristella Alessio
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
| | - Thomas-C Jagau
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
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7
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Luxford TFM, Fedor J, Kočišek J. Electron Energy Loss Processes in Methyl Methacrylate: Excitation and Bond Breaking. J Phys Chem A 2023; 127:2731-2741. [PMID: 36930039 PMCID: PMC10068740 DOI: 10.1021/acs.jpca.2c09077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Details of electron-induced chemistry of methyl methacrylate (MMA) upon complexation are revealed by combining gas-phase 2D electron energy loss spectroscopy with electron attachment spectroscopy of isolated MMA and its clusters. We show that even though isolated MMA does not form stable parent anions, it efficiently thermalizes the incident electrons via intramolecular vibrational redistribution, leading to autodetachment of slow electrons. This autodetachment channel is reduced in clusters due to intermolecular energy transfer and stabilization of parent molecular anions. Bond breaking via dissociative electron attachment leads to an extensive range of anion products. The dominant OCH3- channel is accessible via core-excited resonances with threshold above 5 eV, despite the estimated thermodynamic threshold below 3 eV. This changes in clusters, where MnOCH3- anions are observed in a lower-lying resonance due to neutral dissociation of the 1(n, π*) state and electron self-scavenging. The present findings have implications for electron-induced chemistry in lithography with poly(methyl methacrylate).
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Affiliation(s)
- Thomas F M Luxford
- J. Heyrovský Institute of Physical Chemistry of CAS, Dolejškova 3, 18223 Prague, Czech Republic
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry of CAS, Dolejškova 3, 18223 Prague, Czech Republic
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry of CAS, Dolejškova 3, 18223 Prague, Czech Republic
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8
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Ovad T, Sapunar M, Sršeň Š, Slavíček P, Mašín Z, Jones NC, Hoffmann SV, Ranković M, Fedor J. Excitation and fragmentation of the dielectric gas C 4F 7N: Electrons vs photons. J Chem Phys 2023; 158:014303. [PMID: 36610949 DOI: 10.1063/5.0130216] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
C4F7N is a promising candidate for the replacement of sulfur hexafluoride as an insulating medium, and it is important to understand the chemical changes initiated in the molecule by collision with free electrons, specifically the formation of neutral fragments. The first step of neutral fragmentation is electronic excitation, yet neither the absorption spectrum in the vacuum ultraviolet (VUV) region nor the electron energy loss spectrum have previously been reported. Here, we experimentally probed the excited states by VUV photoabsorption spectroscopy and electron energy loss spectroscopy (EELS). We found that the distribution of states populated upon electron impact with low-energy electrons is significantly different from that following photoabsorption. This difference was confirmed and interpreted with ab initio modeling of both VUV and EELS spectra. We propose here a new computational protocol for the simulation of EELS spectra combining the Born approximation with approximate forms of correlated wave functions, which allows us to calculate the (usually very expensive) scattering cross sections at a cost similar to the calculation of oscillator strengths. Finally, we perform semi-classical non-adiabatic dynamics simulations to investigate the possible neutral fragments of the molecule formed through electron-induced neutral dissociation. We show that the product distribution is highly non-statistical.
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Affiliation(s)
- Tomáš Ovad
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Marin Sapunar
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Štěpán Sršeň
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Petr Slavíček
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Zdeněk Mašín
- Faculty of Mathematics and Physics, Charles University, Institute of Theoretical Physics, V Holešovičkách 2, 18000 Prague, Czech Republic
| | - Nykola C Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Miloš Ranković
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, Prague 8, Czech Republic
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, Prague 8, Czech Republic
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9
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Theoretical study of CO adsorption on FexCuy (x + y = 3) clusters and reactive activity of their carbonyl complexes. Theor Chem Acc 2022. [DOI: 10.1007/s00214-022-02918-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Ranković M, Nag P, Anstöter CS, Mensa-Bonsu G, Kumar T P R, Verlet JRR, Fedor J. Resonances in nitrobenzene probed by the electron attachment to neutral and by the photodetachment from anion. J Chem Phys 2022; 157:064302. [PMID: 35963718 DOI: 10.1063/5.0101358] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We probe resonances (transient anions) in nitrobenzene with the focus on the electron emission from these. Experimentally, we populate resonances in two ways: either by the impact of free electrons on the neutral molecule or by the photoexcitation of the bound molecular anion. These two excitation means lead to transient anions in different initial geometries. In both cases, the anions decay by electron emission and we record the electron spectra. Several types of emission are recognized, differing by the way in which the resulting molecule is vibrationally excited. In the excitation of specific vibrational modes, distinctly different modes are visible in electron collision and photodetachment experiments. The unspecific vibrational excitation, which leads to the emission of thermal electrons following the internal vibrational redistribution, shows similar features in both experiments. A model for the thermal emission based on a detailed balance principle agrees with the experimental findings very well. Finally, a similar behavior in the two experiments is also observed for a third type of electron emission, the vibrational autodetachment, which yields electrons with constant final energies over a broad range of excitation energies. The entrance channels for the vibrational autodetachment are examined in detail, and they point to a new mechanism involving a reverse valence to non-valence internal conversion.
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Affiliation(s)
- Miloš Ranković
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Pamir Nag
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Golda Mensa-Bonsu
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Ragesh Kumar T P
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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11
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Prosvetov A, Verkhovtsev AV, Sushko G, Solov'yov AV. Atomistic simulation of the FEBID-driven growth of iron-based nanostructures. Phys Chem Chem Phys 2022; 24:10807-10819. [PMID: 35475429 DOI: 10.1039/d2cp00809b] [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 growth of iron-containing nanostructures in the process of focused electron beam-induced deposition (FEBID) of Fe(CO)5 is studied by means of atomistic irradiation-driven molecular dynamics (IDMD) simulations. The geometrical characteristics (lateral size, height and volume), morphology and metal content of the grown nanostructures are analyzed at different irradiation and precursor replenishment conditions corresponding to the electron-limited and precursor-limited regimes (ELR & PLR) of FEBID. A significant variation of the deposit's morphology and elemental composition is observed with increasing the electron current from 1 to 4 nA. At low beam current (1 nA) corresponding to the ELR and a low degree of Fe(CO)5 fragmentation, the nanogranular structures are formed which consist of isolated iron clusters embedded into an organic matrix. In this regime, metal clusters do not coalesce with increasing electron fluence, resulting in relatively low metal content of the nanostructures. A higher beam current of 4 nA corresponding to the PLR facilitates the precursor fragmentation and the coalescence of metal clusters into a dendrite-like structure with the size corresponding to the primary electron beam. The IDMD simulations enable atomistic-level predictions on the nanoscopic characterization of the initial phase of nanostructure growth in the FEBID process. These predictions can be verified in high-resolution transmission electron microscopy experiments.
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Affiliation(s)
- Alexey Prosvetov
- MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main, Germany.
| | | | - Gennady Sushko
- MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main, Germany.
| | - Andrey V Solov'yov
- MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main, Germany.
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12
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Shih PY, Cipriani M, Hermanns CF, Oster J, Edinger K, Gölzhäuser A, Ingólfsson O. Low-energy electron interaction and focused electron beam-induced deposition of molybdenum hexacarbonyl (Mo(CO) 6). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:182-191. [PMID: 35186652 PMCID: PMC8822466 DOI: 10.3762/bjnano.13.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Motivated by the potential role of molybdenum in semiconductor materials, we present a combined theoretical and experimental gas-phase study on dissociative electron attachment (DEA) and dissociative ionization (DI) of Mo(CO)6 in comparison to focused electron beam-induced deposition (FEBID) of this precursor. The DEA and DI experiments are compared to previous work, differences are addressed, and the nature of the underlying resonances leading to the observed DEA processes are discussed in relation to an earlier electron transmission study. Relative contributions of individual ionic species obtained through DEA and DI of Mo(CO)6 and the average CO loss per incident are calculated and compared to the composition of the FEBID deposits produced. These are also compared to gas phase, surface science and deposition studies on W(CO)6 and we hypothesize that reductive ligand loss through electron attachment may promote metal-metal bond formation in the deposition process, leading to further ligand loss and the high metal content observed in FEBID for both these compounds.
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Affiliation(s)
- Po-Yuan Shih
- Carl Zeiss SMT GmbH, Industriestraße 1, 64380 Roßdorf, Germany
- Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
| | - Maicol Cipriani
- Science Institute and Department of Chemistry, University of Iceland, Dunhagi 3, 107 Reykjavik, Iceland
| | | | - Jens Oster
- Carl Zeiss SMT GmbH, Industriestraße 1, 64380 Roßdorf, Germany
| | - Klaus Edinger
- Carl Zeiss SMT GmbH, Industriestraße 1, 64380 Roßdorf, Germany
| | - Armin Gölzhäuser
- Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
| | - Oddur Ingólfsson
- Science Institute and Department of Chemistry, University of Iceland, Dunhagi 3, 107 Reykjavik, Iceland
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13
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Sedmidubská B, Luxford TFM, Kočišek J. Electron attachment to isolated and microhydrated favipiravir. Phys Chem Chem Phys 2021; 23:21501-21511. [PMID: 34382983 DOI: 10.1039/d1cp02686k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Electron attachment and its equivalent in complex environments, single-electron reduction, are important in many biological processes. Here, we experimentally study the electron attachment to favipiravir, a well-known antiviral agent. Electron attachment spectroscopy is used to explore the energetics of associative (AEA) and dissociative (DEA) electron attachment to isolated favipiravir. AEA dominates the interaction and the yields of the fragment anions after DEA are an order of magnitude lower than that of the parent anion. DEA primary proceeds via decomposition of the CONH2 functional group, which is supported by reaction threshold calculations using ab initio methods. Mass spectrometry of small favipiravir-water clusters demonstrates that a lot of energy is transferred to the solvent upon electron attachment. The energy gained upon electron attachment, and the high stability of the parent anion were previously suggested as important properties for the action of several electron-affinic radiosensitizers. If any of these mechanisms cause synergism in chemo-radiation therapy, favipiravir could be repurposed as a radiosensitizer.
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Affiliation(s)
- Barbora Sedmidubská
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic. and Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 11519 Prague, Czech Republic
| | - Thomas F M Luxford
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
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14
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Khatymov RV, Terentyev AG. Resonant electron capture negative ion mass spectrometry: the state of the art and the potential for solving analytical problems. Russ Chem Bull 2021. [DOI: 10.1007/s11172-021-3132-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Lengyel J, Pysanenko A, Swiderek P, Heiz U, Fárník M, Fedor J. Water-Assisted Electron-Induced Chemistry of the Nanofabrication Precursor Iron Pentacarbonyl. J Phys Chem A 2021; 125:1919-1926. [PMID: 33651608 DOI: 10.1021/acs.jpca.1c00135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Focused electron beam deposition often requires the use of purification techniques to increase the metal content of the respective deposit. One of the promising methods is adding H2O vapor as a reactive agent during the electron irradiation. However, various contrary effects of such addition have been reported depending on the experimental condition. We probe the elementary electron-induced processes that are operative in a heterogeneous system consisting of iron pentacarbonyl as an organometallic precursor and water. We use an electron beam of controlled energy that interacts with free mixed Fe(CO)5/H2O clusters. These mimic the heterogeneous system and, at the same time, allow direct mass spectrometric analysis of the reaction products. The anionic decomposition pathways are initiated by dissociative electron attachment (DEA), either to Fe(CO)5 or to H2O. The former one proceeds mainly at low electron energies (<3 eV). Comparison of nonhydrated and hydrated conditions reveals that the presence of water actually stabilizes the ligands against dissociation. The latter one proceeds at higher electron energies (>6 eV), where the DEA to H2O forms OH- in the first reaction step. This intermediate reacts with Fe(CO)5, leading to enhanced decomposition, with the desorption of up to three CO ligands. The present results demonstrate that the water action on Fe(CO)5 decomposition is sensitive to the involved electron energy range and depends on the hydration degree.
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Affiliation(s)
- Jozef Lengyel
- Chair of Physical Chemistry, Department of Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Andriy Pysanenko
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Petra Swiderek
- Institute of Applied and Physical Chemistry, Faculty 2 (Chemistry/Biology), University of Bremen, Leobener Strasse 5, 28359 Bremen, Germany
| | - Ueli Heiz
- Chair of Physical Chemistry, Department of Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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Pysanenko A, Grygoryeva K, Kočišek J, Kumar T P R, Fedor J, Ončák M, Fárník M. Stability of pyruvic acid clusters upon slow electron attachment. Phys Chem Chem Phys 2021; 23:4317-4325. [PMID: 33587076 DOI: 10.1039/d0cp06464e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyruvic acid represents a key molecule in prebiotic chemistry and it has recently been proposed to be synthesized on interstellar ices. In order to probe the stability of pyruvic acid in the interstellar medium with respect to decomposition by slow electrons, we investigate the electron attachment to its homomolecular and heteromolecular clusters. Using mass spectrometry, we follow the changes in the fragmentation pattern and its dependence on the electron energy for various cluster sizes of pure and microhydrated pyruvic acid. The assignment of fragmentation reaction pathways is supported by ab initio calculations. The fragmentation degree dramatically decreases upon clustering. This decrease is even stronger in the heteromolecular clusters of pyruvic acid with water, where the non-dissociative attachment is by far the strongest channel. In the homomolecular clusters, the dissociative channel leading to dehydrogenation is active over a larger electron energy range than in the isolated molecules. To probe the role of the self-scavenging effects, we explore the excited states of pyruvic acid. This has been done both experimentally, by using electron energy loss spectroscopy, and theoretically, by photochemical calculations. Data on both optically-allowed and forbidden states allow for the explanation of processes emerging upon clustering.
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Affiliation(s)
- Andriy Pysanenko
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.
| | - Kateryna Grygoryeva
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.
| | - Ragesh Kumar T P
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.
| | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague, Czech Republic.
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Kopyra J, Rabilloud F, Wierzbicka P, Abdoul-Carime H. Energy-Selective Decomposition of Organometallic Compounds by Slow Electrons: The Case of Chloro(dimethyl sulfide)gold(I). J Phys Chem A 2021; 125:966-972. [PMID: 33492965 DOI: 10.1021/acs.jpca.0c09988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Gold-containing compounds offer many applications in nanoscale materials science, and electron-beam methods are versatile for shaping nanostructures. In this study, we report the energy-selective fragmentation of chloro(dimethyl sulfide)gold(I) (ClAuS(CH3)2) induced by slow electrons. We observe the resonant formation of four fragment anions, namely [Cl]-, [S]-, [CH2S]-, and [ClAuH···SH]-, which are generated in the energy range of 0-9 eV. The predominant fragment anion is formed below 1 eV from the cleavage of a single Au-Cl bond to produce the [Cl]- anion. The resonant states and the energetics of the fragmentation are investigated by DFT methods. These findings may contribute to future strategies in the elaboration of specific nanomaterials or for selective chemistry using electron-beam techniques.
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Affiliation(s)
- Janina Kopyra
- Faculty of Exact and Natural Sciences, Siedlce University of Natural Sciences and Humanities, 3 Maja 54, 08-110 Siedlce, Poland
| | - Franck Rabilloud
- Universite de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, UMR5306, F-69622 Villeurbanne, France
| | - Paulina Wierzbicka
- Faculty of Exact and Natural Sciences, Siedlce University of Natural Sciences and Humanities, 3 Maja 54, 08-110 Siedlce, Poland
| | - Hassan Abdoul-Carime
- Université de Lyon, Université Lyon 1, CNRS, Institut de Physique des 2 Infinis de Lyon/IN2P3, UMR5822, F-69003 Lyon, France
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18
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Kopyra J, Rabilloud F, Abdoul-Carime H. Decomposition of Bis(acetylacetonate)zinc(II) by Slow Electrons. Inorg Chem 2020; 59:12788-12792. [PMID: 32830979 DOI: 10.1021/acs.inorgchem.0c01842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The production of zinc-containing nanostructures has a large variety of applications. Using electron beam techniques to degrade organometallic molecules for that purpose is perhaps one of the most versatile methods. In this work, we investigate the scattering of low-energy (<12 eV) electrons with bis(acetylacetonate)zinc(II) molecules. We show that core excited and high-lying shape resonances are mainly responsible for the production of the precursor anions as well as the ligand negative fragments, which are observed exclusively at electron energies of >3 eV. The mechanisms for electron capture and then molecular dissociation are discussed in terms of density functional theory studies.
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Affiliation(s)
- Janina Kopyra
- Faculty of Exact and Natural Sciences, Siedlce University of Natural Sciences and Humanities, 08-110 Siedlce, Poland
| | - Franck Rabilloud
- Universite de Lyon, Universite Claude Bernard Lyon 1, CNRS, Institut Lumiere Matiere, UMR5306, F-69622 Villeurbanne, France
| | - Hassan Abdoul-Carime
- Universite de Lyon, Universite Lyon 1, Institut de Physique des 2 Infinis, CNRS/IN2P3, UMR5822, F-69003 Lyon, France
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19
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20
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Ranković M, Kumar T P R, Nag P, Kočišek J, Fedor J. Temporary anions of the dielectric gas C 3F 7CN and their decay channels. J Chem Phys 2020; 152:244304. [PMID: 32610971 DOI: 10.1063/5.0008897] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We probe the transient anion states (resonances) in the dielectric gas C4F7N by the electron energy loss spectroscopy and the dissociative electron attachment spectroscopy. The vibrationally inelastic electron scattering leads to two excitation types. The first is the excitation of specific vibrational modes that are assigned with the help of an infrared spectrum of this molecule and quantum chemistry calculations. In the second type of vibrational excitation, the excess energy is randomized via internal vibrational redistribution in the temporary anion, and the electrons are emitted statistically. The electron attachment proceeds in three different regimes. The first is the formation of the parent C4F7N- anion at energies close to 0 eV. The second is a statistical evaporation of the F-atom, leading to the defluorinated anion C4F6N-. Finally, the third is dissociative electron attachment proceeding via the formation of several resonances and leading to a number of fragments. The present data explain the puzzling recent results of the pulsed-Townsend experiments with this gas.
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Affiliation(s)
- M Ranković
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Ragesh Kumar T P
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - P Nag
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Kočišek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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21
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Anstöter CS, Mensa-Bonsu G, Nag P, Ranković M, Kumar T P R, Boichenko AN, Bochenkova AV, Fedor J, Verlet JRR. Mode-Specific Vibrational Autodetachment Following Excitation of Electronic Resonances by Electrons and Photons. PHYSICAL REVIEW LETTERS 2020; 124:203401. [PMID: 32501066 DOI: 10.1103/physrevlett.124.203401] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
Electronic resonances commonly decay via internal conversion to vibrationally hot anions and subsequent statistical electron emission. We observed vibrational structure in such an emission from the nitrobenzene anion, in both the 2D electron energy loss and 2D photoelectron spectroscopy of the neutral and anion, respectively. The emission peaks could be correlated with calculated nonadiabatic coupling elements for vibrational modes to the electronic continuum from a nonvalence dipole-bound state. This autodetachment mechanism via a dipole-bound state is likely to be a common feature in both electron and photoelectron spectroscopies.
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Affiliation(s)
- Cate S Anstöter
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Golda Mensa-Bonsu
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Pamir Nag
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Miloš Ranković
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Ragesh Kumar T P
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Anton N Boichenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Juraj Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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22
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Med J, Sršeň Š, Slavíček P, Domaracka A, Indrajith S, Rousseau P, Fárník M, Fedor J, Kočišek J. Vibrationally Mediated Stabilization of Electrons in Nonpolar Matter. J Phys Chem Lett 2020; 11:2482-2489. [PMID: 32154726 DOI: 10.1021/acs.jpclett.0c00278] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We explore solvation of electrons in nonpolar matter, here represented by butadiene clusters. Isolated butadiene supports only the existence of transient anions (resonances). Two-dimensional electron energy loss spectroscopy shows that the resonances lead to an efficient vibrational excitation of butadiene, which can result into the almost complete loss of energy of the interacting electron. Cluster-beam experiments show that molecular clusters of butadiene form stable anions, however only at sizes of more than 9 molecular units. We have calculated the distribution of electron affinities of clusters using classical and path integral molecular dynamics simulations. There is almost a continuous transition from the resonant to the bound anions with an increase in cluster size. The comparison of the classical and quantum dynamics reveals that the electron binding is strongly supported by molecular vibrations, brought about by nuclear zero-point motion and thermal agitation. We also inspected the structure of the solvated electron, finding it well localized.
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Affiliation(s)
- Jakub Med
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague 6, Czech Republic
| | - Štěpán Sršeň
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague 6, Czech Republic
| | - Petr Slavíček
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague 6, Czech Republic
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - A Domaracka
- Normandie Univ., ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, 14000 Caen, France
| | - S Indrajith
- Normandie Univ., ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, 14000 Caen, France
| | - P Rousseau
- Normandie Univ., ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, 14000 Caen, France
| | - M Fárník
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Fedor
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Kočišek
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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23
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Chen WT, Hsu CW, Lee JF, Pao CW, Hsu IJ. Theoretical Analysis of Fe K-Edge XANES on Iron Pentacarbonyl. ACS OMEGA 2020; 5:4991-5000. [PMID: 32201785 PMCID: PMC7081404 DOI: 10.1021/acsomega.9b03887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/21/2020] [Indexed: 05/21/2023]
Abstract
Iron pentacarbonyl (Fe(CO)5) is a versatile material that is utilized as an inhibitor of flame, shows soot suppressibility, and is used as a precursor for focused electron-beam-induced deposition (FEBID). X-ray absorption near-edge structure (XANES) of the K edge, which is a powerful technique for monitoring the oxidation states and coordination environment of metal sites, can be used to gain insight into Fe(CO)5-related reaction mechanisms in in situ experiments. We use a finite difference method (FDM) and molecular-orbital-based time-dependent density functional theory (TDDFT) calculations to clarify the Fe K-edge XANES features of Fe(CO)5. The two pre-edge peaks P1 and P2 are mainly the Fe(1s) → Fe-C(σ*) and Fe(1s) → Fe-C(π*) transitions, respectively. When the geometry transformed from D 3h to C 4v symmetry, a ∼30% decrease of the pre-edge P2 intensity was observed in the simulated spectra. This implies that the π bonding of Fe and CO is sensitive to changes in geometry. The following rising edge and white line regions are assigned to the Fe(1s) → Fe(4p)(mixing C(2p)) transitions. Our results may provide useful information to interpret XANES spectra variations of in situ reactions of metal-CO or similar compounds with π acceptor ligandlike metal-CN complexes.
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Affiliation(s)
- Wei-Ting Chen
- Department
of Molecular Science and Engineering, National
Taipei University of Technology, Taipei 10608, Taiwan
| | - Che-Wei Hsu
- Department
of Molecular Science and Engineering, National
Taipei University of Technology, Taipei 10608, Taiwan
| | - Jyh-Fu Lee
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chih-Wen Pao
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - I-Jui Hsu
- Department
of Molecular Science and Engineering, National
Taipei University of Technology, Taipei 10608, Taiwan
- Research
and Development Center for Smart Textile Technology, National Taipei University of Technology, Taipei 10608, Taiwan
- E-mail: .
Tel: +886-2-27712171#2420
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24
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Khatymov RV, Shchukin PV, Muftakhov MV, Yakushchenko IK, Yarmolenko OV, Pankratyev EY. A unified statistical RRKM approach to the fragmentation and autoneutralization of metastable molecular negative ions of hexaazatrinaphthylenes. Phys Chem Chem Phys 2020; 22:3073-3088. [PMID: 31965122 DOI: 10.1039/c9cp05397b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the compounds promising for use as n-type semiconductors in organic electronics and energy storage devices, hexaazatrinaphthylene (HATNA) and its derivative hexamethoxy-hexaazatrinaphthylene (HMHATA), the monomolecular processes occurring under the exposure of molecules to low-energy (0-15 eV) free electrons were studied by means of resonant electron capture negative ion mass spectrometry. Resonant electron attachment results in the formation of eminently long-lived molecular negative ions (MNIs) in an abnormally wide range of incident electron energy (Ee) from 0 to 5-7 eV. For both compounds, this observation serves as an indication of the strong electron-accepting properties and high stability of MNIs against electron autodetachment. A weak yield of the only fragment NIs, dehydrogenated anions, was detected for HATNA at Ee > 6 eV. MNIs of HMHATA are less stable to dissociative decay because of the presence of weakly bound terminal substituents. This is evidenced by the mass spectral observation of intense fragmentation occurring above Ee≈ 1 eV and leading to a loss of up to 3 methyl groups as the Ee increases. A series of metastable NI peaks observed in the mass spectra testify to the delayed and sequential nature of fragmentation. Based on the principles of statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory, the theoretical model of dissociative decay of NIs was developed and then adopted to quantify the rates of ground-state anion decay via electron autodetachment. The experimentally measured electron autodetachment lifetimes and fragmentation rates were best reproduced by the model at molecular adiabatic electron affinities preset to 2.15 eV for HATNA and 1.88 eV for HMHATA, in reasonable agreement with the quantum chemical DFT PBE/3ζ predictions.
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Affiliation(s)
- Rustem V Khatymov
- Institute of Molecule and Crystal Physics, Ufa Federal Research Centre of the Russian Academy of Sciences, Ufa 450075, Russia.
| | - Pavel V Shchukin
- Institute of Molecule and Crystal Physics, Ufa Federal Research Centre of the Russian Academy of Sciences, Ufa 450075, Russia.
| | - Mars V Muftakhov
- Institute of Molecule and Crystal Physics, Ufa Federal Research Centre of the Russian Academy of Sciences, Ufa 450075, Russia.
| | - Igor K Yakushchenko
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia
| | - Ol'ga V Yarmolenko
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia
| | - Evgeniy Yu Pankratyev
- Institute of Molecule and Crystal Physics, Ufa Federal Research Centre of the Russian Academy of Sciences, Ufa 450075, Russia.
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25
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Ferreira da Silva F, Thorman RM, Bjornsson R, Lu H, McElwee-White L, Ingólfsson O. Dissociation of the FEBID precursor cis-Pt(CO) 2Cl 2 driven by low-energy electrons. Phys Chem Chem Phys 2020; 22:6100-6108. [PMID: 32025665 DOI: 10.1039/c9cp06633k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we present experimental and theoretical results on dissociative electron attachment and dissociative ionisation for the potential FEBID precursor cis-Pt(CO)2Cl2. UHV surface studies have shown that high purity platinum deposits can be obtained from cis-Pt(CO)2Cl2. The efficiency and energetics of ligand removal through these processes are discussed and experimental appearance energies are compared to calculated thermochemical thresholds. The present results demonstrate the potential effectiveness of electron-induced reactions in the deposition of this FEBID precursor, and these are discussed in conjunction with surface science studies on this precursor and the design of new FEBID precursors.
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Affiliation(s)
- Filipe Ferreira da Silva
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
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26
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Kumar T P R, Kočišek J, Bravaya K, Fedor J. Electron-induced vibrational excitation and dissociative electron attachment in methyl formate. Phys Chem Chem Phys 2020; 22:518-524. [PMID: 31829379 DOI: 10.1039/c9cp05165a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We probe the low-energy electron collisions with methyl formate HCOOCH3, focusing on its resonant states. Experimentally, we (i) use two-dimensional electron energy loss spectroscopy to gain information about the vibrational excitation and (ii) report the absolute dissociative electron attachment cross sections. The electron scattering spectra reveal both the threshold effects due to the long-range electron-molecule interaction and a pronounced π* resonance centered around 2.1 eV. This resonance gives rise to dissociative electron attachment into three different anionic channels, the strongest one being the production of the formate anion. Theoretically, we characterize this resonant state using the complex absorbing potential approach combined with multistate multireference perturbation theory, which predicts its position and width in excellent agreement with the experiment.
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Affiliation(s)
- Ragesh Kumar T P
- J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic.
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27
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Zawadzki M, Chachereau A, Kočišek J, Franck CM, Fedor J. Electron attachment to hexafluoropropylene oxide (HFPO). J Chem Phys 2018; 149:204305. [PMID: 30501269 DOI: 10.1063/1.5051724] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We probe the electron attachment in hexafluoropropylene oxide (HFPO), C3F6O, a gas widely used in plasma technologies. We determine the absolute electron attachment cross section using two completely different experimental approaches: (i) a crossed-beam experiment at single collision conditions (local pressures of 5 × 10-4 mbar) and (ii) a pulsed Townsend experiment at pressures of 20-100 mbar. In the latter method, the cross sections are unfolded from the electron attachment rate coefficients. The cross sections derived independently by the two methods are in very good agreement. We additionally discuss the dissociative electron attachment fragmentation patterns and their role in the radical production in industrial HFPO plasmas.
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Affiliation(s)
- M Zawadzki
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - A Chachereau
- Power Systems and High Voltage Laboratories, ETH Zurich, Physikstr. 3, 8092 Zurich, Switzerland
| | - J Kočišek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - C M Franck
- Power Systems and High Voltage Laboratories, ETH Zurich, Physikstr. 3, 8092 Zurich, Switzerland
| | - J Fedor
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
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