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Falcinelli S, Farrar JM, Vecchiocattivi F, Pirani F. Quantum-State Controlled Reaction Channels in Chemi-ionization Processes: Radiative (Optical-Physical) and Exchange (Oxidative-Chemical) Mechanisms. Acc Chem Res 2020; 53:2248-2260. [PMID: 32930573 PMCID: PMC8011800 DOI: 10.1021/acs.accounts.0c00371] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Indexed: 01/29/2023]
Abstract
ConspectusMost chemical processes are triggered by electron or charge transfer phenomena (CT). An important class of processes involving CT are chemi-ionization reactions. Such processes are very common in nature, involving neutral species in ground or excited electronic states with sufficient energy (X*) to yield ionic products, and are considered as the primary initial step in flames. They are characterized by pronounced electronic rearrangements that take place within the collisional complex (X···M)* formed by approaching reagents, as shown by the following scheme, where M is an atomic or molecular target: X* + M → (X···M)* → [(X+···M) ↔ (X···M+)]e- → via e - CT (X···M)+ + e- → final ions.Despite their important role in fundamental and applied research, combustion, plasmas, and astrochemistry, a unifying description of these basic processes is still lacking. This Account describes a new general theoretical methodology that demonstrates, for the first time, that chemi-ionization reactions are prototypes of gas phase oxidation processes occurring via two different microscopic mechanisms whose relative importance varies with collision energy, Ec, and separation distance, R. These mechanisms are illustrated for simple collisions involving Ne*(3P2,0) and noble gases (Ng). In thermal and hyperthermal collisions probing interactions at intermediate and short R, the transition state [(Ne···Ng)+]e- is a molecular species described as a molecular ion core with an orbiting Rydberg electron in which the neon reagent behaves as a halogen atom (i.e., F) with high electron affinity promoting chemical oxidation. Conversely, subthermal collisions favor a different reaction mechanism: Ng chemi-ionization proceeds through another transition state [Ne*······Ng], a weakly bound diatomic-lengthened complex where Ne* reagent, behaving as a Na atom, loses its metastability and stimulates an electron ejection from M by a concerted emission-absorption of a "virtual" photon. This is a physical radiative mechanism promoting an effective photoionization. In the thermal regime of Ec, there is a competition between these two mechanisms. The proposed method overcomes previous approaches for the following reasons: (1) it is consistent with all assumptions invoked in previous theoretical descriptions dating back to 1970; (2) it provides a simple and general description able to reproduce the main experimental results from our and other laboratories during last 40 years; (3) it demonstrates that the two "exchange" and "radiative" mechanisms are simultaneously present with relative weights that change with Ec (this viewpoint highlights the fact that the "canonical" chemical oxidation process, dominant at high Ec, changes its nature in the subthermal regime to a direct photoionization process; therefore, it clarifies differences between the cold chemistry of terrestrial and interstellar environments and the energetic one of combustion and flames); (4) the proposed method explicitly accounts for the influence of the degree of valence orbital alignment on the selective role of each reaction channel as a function of Ec and also permits a description of the collision complex, a rotating adduct, in terms of different Hund's cases of angular momentum couplings that are specific for each reaction channel; (5) finally, the method can be extended to reaction mechanisms of redox, acid-base, and other important condensed phase reactions.
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Affiliation(s)
- Stefano Falcinelli
- Dipartimento
di Ingegneria Civile ed Ambientale, Università
di Perugia, 06125 Perugia, Italy
| | - James M. Farrar
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Franco Vecchiocattivi
- Dipartimento
di Ingegneria Civile ed Ambientale, Università
di Perugia, 06125 Perugia, Italy
| | - Fernando Pirani
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università
di Perugia, 06123 Perugia, Italy
- Istituto
di Scienze e Tecnologie Chimiche “G. Natta” CNR-SCITEC, 06123 Perugia, Italy
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Zou J, Osterwalder A. Investigation of the low-energy stereodynamics in the Ne( 3P 2) + N 2, CO reactions. J Chem Phys 2020; 153:104306. [PMID: 32933296 DOI: 10.1063/5.0022053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We report on an experimental investigation of the low-energy stereodynamics of the energy transfer reactions Ne(3P2) + X, producing Ne(1S) + X+ and [Ne-X]+ (X = N2 or CO). Collision energies in the range 0.2 K-700 K are obtained by using the merged beam technique. Two kinds of product ions are generated by Penning and associative ionization, respectively. The intermediate product [Ne-X]+ in vibrationally excited states can predissociate into bare ions (X+). The experimental ratio of the NeX+ and X+ product ion yields is similar for both molecules at high collision energies but diverge at collision energies below 100 K. This difference is explained by the first excited electronic state of the product ions, which is accessible in the case of CO but lies too high in energy in the case of N2.
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Affiliation(s)
- Junwen Zou
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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Falcinelli S, Rosi M. Production and Characterization of Molecular Dications: Experimental and Theoretical Efforts. Molecules 2020; 25:molecules25184157. [PMID: 32932839 PMCID: PMC7571021 DOI: 10.3390/molecules25184157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 11/16/2022] Open
Abstract
Molecular dications are doubly charged cations of importance in flames, plasma chemistry and physics and in the chemistry of the upper atmosphere of Planets. Furthermore, they are exotic species able to store a considerable amount of energy at a molecular level. This high energy content of several eV can be easily released as translational energy of the two fragment monocations generated by their Coulomb explosion. For such a reason, they were proposed as a new kind of alternative propellant. The present topic review paper reports on an overview of the main contributions made by the authors’ research groups in the generation and characterization of simple molecular dications during the last 40 years of coupling experimental and theoretical efforts.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
- Correspondence: (S.F.); (M.R.); Tel.: +39-075-585-3862 (S.F.); +39-075-585-3858 (M.R.)
| | - Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
- SCITEC, CNR, Via Elce di Sotto 8, 06123 Perugia, Italy
- Correspondence: (S.F.); (M.R.); Tel.: +39-075-585-3862 (S.F.); +39-075-585-3858 (M.R.)
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Falcinelli S, Vecchiocattivi F, Pirani F. General treatment for stereo-dynamics of state-to-state chemi-ionization reactions. Commun Chem 2020; 3:64. [PMID: 36703400 PMCID: PMC9814700 DOI: 10.1038/s42004-020-0312-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/30/2020] [Indexed: 01/29/2023] Open
Abstract
The investigation of chemi-ionization processes provides unique information on how the reaction dynamics depend on the energy and structure of the transition state which relate to the symmetry, relative orientation of reagent/product valence electron orbitals, and selectivity of electronic rearrangements. Here we propose a theoretical approach to formulate the optical potential for Ne*(3P2,0) noble gas atom chemi-ionizations as prototype oxidation processes. We include the selective role of atomic alignment and of the electron transfer mechanism. The state-to-state reaction probability is evaluated and a unifying description of the main experimental findings is obtained. Further, we reproduce the results of recent and advanced molecular beam experiments with a state selected Ne* beam.The selective role of electronic rearrangements within the transition state, quantified through the use of suitable operative relations, could cast light on many other chemical processes more difficult to characterize.
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Affiliation(s)
- Stefano Falcinelli
- grid.9027.c0000 0004 1757 3630Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Franco Vecchiocattivi
- grid.9027.c0000 0004 1757 3630Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Fernando Pirani
- grid.9027.c0000 0004 1757 3630Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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Falcinelli S, Pirani F, Candori P, Brunetti BG, Farrar JM, Vecchiocattivi F. A New Insight on Stereo-Dynamics of Penning Ionization Reactions. Front Chem 2019; 7:445. [PMID: 31275926 PMCID: PMC6591474 DOI: 10.3389/fchem.2019.00445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/31/2019] [Indexed: 12/25/2022] Open
Abstract
Recent developments in the experimental study of Penning ionization reactions are presented here to cast light on basic aspects of the stereo-dynamics of the microscopic mechanisms involved. They concern the dependence of the reaction probability on the relative orientation of the atomic and molecular orbitals of reagents and products. The focus is on collisions between metastable Ne*(3P2, 0) atoms with other noble gas atoms or molecules, for which play a crucial role both the inner open-shell structure of Ne* and the HOMO orbitals of the partner. Their mutual orientation with respect to the intermolecular axis controls the characteristics of the intermolecular potential, which drives the collision dynamics and the reaction probability. The investigation of ionization processes of water, the prototype of hydrogenated molecules, suggested that the ground state of water ion is produced when Ne* approaches H2O perpendicularly to its plane. Conversely, collisions addressed toward the lone pair, aligned along the water C2v symmetry axis, generates electronically excited water ions. However, obtained results refer to a statistical/random orientation of the open shell ionic core of Ne*. Recently, the attention focused on the ionization of Kr or Xe by Ne*, for which we have been able to characterize the dependence on the collision energy of the branching ratio between probabilities of spin orbit resolved elementary processes. The combined analysis of measured PIES spectra suggested the occurrence of contributions from four different reaction channels, assigned to two distinct spin-orbit states of the Ne*(3P2, 0) reagent and two different spin-orbit states of the ionic M+(2P3/2, 1/2) products (M = Kr, Xe). The obtained results emphasized the reactivity change of 3P0 atoms with respect to 3P2, in producing ions in 2P3/2 and 2P1/2 sublevels, as a function of the collision energy. These findings have been assumed to arise from a critical balance of adiabatic and non-adiabatic effects that control formation and electronic rearrangement of the collision complex, respectively. From these results we are able to characterize for the first time, according to our knowledge, the state to state reaction probability for the ionization of Kr and Xe by Ne* in both 3P2 and 3P0 sublevels.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Pietro Candori
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Brunetto G Brunetti
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - James M Farrar
- Department of Chemistry, University of Rochester, Rochester, NY, United States
| | - Franco Vecchiocattivi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
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Falcinelli S, Vecchiocattivi F, Pirani F. The electron couplings in the transition states: The stereodynamics of state to state autoionization processes. J Chem Phys 2019; 150:044305. [PMID: 30709283 DOI: 10.1063/1.5051174] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Measurements of the kinetic energy distribution of electrons, emitted in collision between Ne*(3P2,0) and Kr(1S0) and Xe(1S0), have been performed in a crossed molecular beam apparatus which employs a mass spectrometer and a hemispherical electron analyzer as detectors. The analysis of the obtained experimental results provides new insights on electronic rearrangements and electronic angular momentum coupling effects that determine relevant properties of the transition state of autoionization processes, and that we have found useful to classify as adiabatic and non-adiabatic effects. In particular, while the adiabatic effects control sequence, energy, and symmetry of quantum states accessible to both reagents and products in the probed collision energy range, the non-adiabatic ones trigger the passage from entrance to exit channels. The obtained results are important not only to compact previous theoretical schemes of autoionization reactions in a unified representation but also to cast light on the role of electronic rearrangements within the transition state of many other types of chemical processes that are more difficult to characterize.
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Affiliation(s)
- Stefano Falcinelli
- Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Franco Vecchiocattivi
- Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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Sebastiani B, Giorgini M, Falcinelli S. Chemical Characterization of Lodoicea maldivica Fruit. Chem Biodivers 2017; 14. [PMID: 28452174 DOI: 10.1002/cbdv.201700109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/25/2017] [Indexed: 11/12/2022]
Abstract
In the present study, we report the attempt to characterize the chemical composition of fruit kernel of Lodoicea maldivica coco nucifera palm (commonly named as 'Coco de mer') by gas chromatographic method. The analysis was performed by HS-SPME and GC/MS techniques to determine volatile aroma, sterol, and fatty acid composition profiles in the internal and external pulp of two distinct coconuts. Although no qualitative differences in flavour composition were observed between the two analysed coconuts and the relative two pulp parts, variations in the abundance levels of the prominent compounds have been recorded. The averaged quantity of total phytosterols, resulting from the two analysed 'Coco de mer' samples, was almost constant in both kernels coconut, being 24.5 μg/g (of dry net matter) for the external, and 26.9 μg/g (of dry net matter) for the internal portion. In both coconuts, the fatty acid pattern composition was characterized by seven saturated acids ranged from C14:0 (myristic) to C20:0 (arachidic) and two monounsaturated acids, the palmitoleic (C16:1, ω7) and the oleic (C18:1, ω9). Palmitic acid (C16:0) was the predominant one with an average contribution of about 49.0%, followed by pentadecanoic 16.5%, stearic (C18:0) 11.6%, and myristic (C14:0) 9.9% acids in all two examined kernel portions.
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Affiliation(s)
- Bartolomeo Sebastiani
- Department of Chemistry Biology and Biotechnologies, University of Perugia, Via Elce di Sotto, 8, 06123, Perugia, Italy
| | | | - Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125, Perugia, Italy
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Falcinelli S, Candori P, Pirani F, Vecchiocattivi F. The role of charge transfer in the stability and reactivity of chemical systems from experimental findings. Phys Chem Chem Phys 2017; 19:6933-6944. [DOI: 10.1039/c7cp00614d] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phenomena are described within a unifying picture, by isolating charge/electron transfer as an interaction component triggering chemical reactivity.
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Affiliation(s)
- S. Falcinelli
- Department of Civil and Environmental Engineering
- University of Perugia
- 06125 Perugia
- Italy
| | - P. Candori
- Department of Civil and Environmental Engineering
- University of Perugia
- 06125 Perugia
- Italy
| | - F. Pirani
- Department of Chemistry
- Biology and Biotechnologies
- University of Perugia
- 06123 Perugia
- Italy
| | - F. Vecchiocattivi
- Department of Civil and Environmental Engineering
- University of Perugia
- 06125 Perugia
- Italy
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10
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The escape of O+ ions from the atmosphere: An explanation of the observed ion density profiles on Mars. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Falcinelli S, Rosi M, Cavalli S, Pirani F, Vecchiocattivi F. Stereoselectivity in Autoionization Reactions of Hydrogenated Molecules by Metastable Noble Gas Atoms: The Role of Electronic Couplings. Chemistry 2016; 22:12518-26. [PMID: 27470487 DOI: 10.1002/chem.201601811] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Indexed: 11/09/2022]
Abstract
Focus in the present paper is on the analysis of total and partial ionization cross sections, measured in absolute value as a function of the collision energy, representative of the probability of ionic product formation in selected electronic states in Ne*-H2 O, H2 S, and NH3 collisions. In order to characterize the imaginary part of the optical potential, related to electronic couplings, we generalize a methodology to obtain direct information on the opacity function of these reactions. Such a methodology has been recently exploited to test the real part of the optical potential (S. Falcinelli et al., Chem. Eur. J., 2016, 22, 764-771). Depending on the balance of noncovalent contributions, the real part controls the approach of neutral reactants, the removal of ionic products, and the structure of the transition state. Strength, range, and stereoselectivity of electronic couplings, triggering these and many other reactions, are directly obtained from the present investigation.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125, Perugia, Italy.
| | - Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125, Perugia, Italy
| | - Simonetta Cavalli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology and Biotechnology, 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
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Falcinelli S, Rosi M, Pirani F, Stranges D, Vecchiocattivi F. Measurements of Ionization Cross Sections by Molecular Beam Experiments: Information Content on the Imaginary Part of the Optical Potential. J Phys Chem A 2016; 120:5169-74. [PMID: 26938026 DOI: 10.1021/acs.jpca.6b00795] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, we present and analyze in detail new and recent ionization cross section and mass spectrum determinations, collected in the case of He*, Ne*-H2O, -H2S, and -NH3 ionizing collisions. These sets of data, obtained under the same experimental conditions, are relevant to identify differences in the autoionization stereodynamics of the three hydrogenated molecules and on the selective role of the imaginary part of the optical potential. We demonstrate that in these autoionization processes hydrogen and halogen bonds are competing because they are controlling both real and imaginary components of the optical potential that drives the complete reaction dynamics. In particular, we found that both components critically depend on the angular and radial approach between the reagent partners in determining the collision dynamics.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia , Via G. Duranti 93, 06125 Perugia, Italy
| | - Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia , Via G. Duranti 93, 06125 Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia , Via Elce di Sotto, 8, 06123 Perugia, Italy
| | - Domenico Stranges
- Department of Chemistry, University of Rome "La Sapienza" , 00185 Rome, Italy
| | - Franco Vecchiocattivi
- Department of Civil and Environmental Engineering, University of Perugia , Via G. Duranti 93, 06125 Perugia, Italy
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Falcinelli S, Bartocci A, Cavalli S, Pirani F, Vecchiocattivi F. Stereodynamics in the Collisional Autoionization of Water, Ammonia, and Hydrogen Sulfide with Metastable Rare Gas Atoms: Competition Between Intermolecular Halogen and Hydrogen Bonds. Chemistry 2015; 22:764-71. [DOI: 10.1002/chem.201503692] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 11/07/2022]
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Falcinelli S, Bartocci A, Cavalli S, Pirani F, Vecchiocattivi F. The stereo-dynamics of collisional autoionization of ammonia by helium and neon metastable excited atoms through molecular beam experiments. J Chem Phys 2015; 143:164306. [DOI: 10.1063/1.4933429] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Alessio Bartocci
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Via Elce di sotto 8, 06123 Perugia, Italy
| | - Simonetta Cavalli
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Via Elce di sotto 8, 06123 Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology, and Biotechnology, 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
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The Possible Role of Penning Ionization Processes in Planetary Atmospheres. ATMOSPHERE 2015. [DOI: 10.3390/atmos6030299] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Falcinelli S, Bartocci A, Candori P, Pirani F, Vecchiocattivi F. Intermolecular potential energy surfaces for the interaction between H 2 X (X O, S) and a metastable Ne * ( 3 P 2,0 ) atom. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Brunetti BG, Candori P, Falcinelli S, Pirani F, Vecchiocattivi F. The stereodynamics of the Penning ionization of water by metastable neon atoms. J Chem Phys 2014; 139:164305. [PMID: 24182027 DOI: 10.1063/1.4826101] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The stereodynamics of the Penning ionization of water molecules by collision with metastable neon atoms, occurring in the thermal energy range, is of great relevance for the understanding of fundamental aspects of the physical chemistry of water. This process has been studied by analyzing the energy spectrum of the emitted electrons previously obtained in our laboratory in a crossed beam experiment [B. G. Brunetti, P. Candori, D. Cappelletti, S. Falcinelli, F. Pirani, D. Stranges, and F. Vecchiocattivi, Chem. Phys. Lett. 539-540, 19 (2012)]. For the spectrum analysis, a novel semiclassical method is proposed, that assumes ionization events as mostly occurring in the vicinities of the collision turning points. The potential energy driving the system in the relevant configurations of the entrance and exit channels, used in the spectrum simulation, has been formulated by the use of a semiempirical method. The analysis puts clearly in evidence how different approaches of the metastable atom to the water molecule lead to ions in different electronic states. In particular, it provides the angular acceptance cones where the selectivity of the process leading to the specific formation of each one of the two energetically possible ionic product states of H2O(+) emerges. It is shown how the ground state ion is formed when neon metastable atoms approach water mainly perpendicularly to the molecular plane, while the first excited electronic state is formed when the approach occurs preferentially along the C2v axis, on the oxygen side. An explanation is proposed for the observed vibrational excitation of the product ions.
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Jankunas J, Bertsche B, Osterwalder A. Study of the Ne(3P2) + CH3F Electron-Transfer Reaction below 1 K. J Phys Chem A 2014; 118:3875-9. [DOI: 10.1021/jp502989g] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Justin Jankunas
- Institute
for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Benjamin Bertsche
- Institute
for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute
for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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Falcinelli S, Candori P, Bettoni M, Pirani F, Vecchiocattivi F. Penning Ionization Electron Spectroscopy of Hydrogen Sulfide by Metastable Helium and Neon Atoms. J Phys Chem A 2014; 118:6501-6. [DOI: 10.1021/jp5030312] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Stefano Falcinelli
- Dipartimento
di Ingegneria Civile ed Ambientale, Università di Perugia, 06125 Perugia, Italy
| | - Pietro Candori
- Dipartimento
di Ingegneria Civile ed Ambientale, Università di Perugia, 06125 Perugia, Italy
| | - Marta Bettoni
- Dipartimento
di Ingegneria Civile ed Ambientale, Università di Perugia, 06125 Perugia, Italy
| | - Fernando Pirani
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy
| | - Franco Vecchiocattivi
- Dipartimento
di Ingegneria Civile ed Ambientale, Università di Perugia, 06125 Perugia, Italy
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Production of ions at high energy and its role in extraterrestrial environments. RENDICONTI LINCEI-SCIENZE FISICHE E NATURALI 2012. [DOI: 10.1007/s12210-012-0215-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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