1
|
Richardson V, Polášek M, Romanzin C, Tosi P, Thissen R, Alcaraz C, Žabka J, Ascenzi D. Reactivity of the Ethenium Cation (C 2H 5+) with Ethyne (C 2H 2): A Combined Experimental and Theoretical Study. Molecules 2024; 29:810. [PMID: 38398562 PMCID: PMC10892252 DOI: 10.3390/molecules29040810] [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: 12/22/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
The gas-phase reaction between the ethyl cation (C2H5+) and ethyne (C2H2) is re-investigated by measuring absolute reactive cross sections (CSs) and branching ratios (BRs) as a function of collision energy, in the thermal and hyperthermal energy range, via tandem-guided ion beam mass spectrometry under single collision conditions. Dissociative photoionization of C2H5Br using tuneable VUV radiation in the range 10.5-14.0 eV is employed to generate C2H5+, which has also allowed us to explore the impact of increasing (vibrational) excitation on the reactivity. Reactivity experiments are complemented by theoretical calculations, at the G4 level of theory, of the relative energies and structures of the most relevant stationary points on the reactive potential energy hypersurface (PES) and by mass-analyzed ion kinetic energy (MIKE) spectrometry experiments to probe the metastable decomposition from the [C4H7]+ PES and elucidate the underlying reaction mechanisms. Two main product channels have been identified at a centre-of-mass collision energy of ∼0.1 eV: (a) C3H3++CH4, with BR = 0.76±0.05 and (b) C4H5++H2, with BR = 0.22±0.02. A third channel giving C2H3+ in association with C2H4 is shown to emerge at both high internal excitation of C2H5+ and high collision energies. From CS measurements, energy-dependent total rate constants in the range 4.3×10-11-5.2×10-10 cm3·molecule-1·s-1 have been obtained. Theoretical calculations indicate that both channels stem from a common covalently bound intermediate, CH3CH2CHCH+, from which barrierless and exothermic pathways exist for the production of both cyclic c-C3H3+ and linear H2CCCH+ isomers of the main product channel. For the minor C4H5+ product, two isomers are energetically accessible: the three-member cyclic isomer c-C3H2(CH3)+ and the higher energy linear structure CH2CHCCH2+, but their formation requires multiple isomerization steps and passages via transition states lying only 0.11 eV below the reagents' energy, thus explaining the smaller BR. Results have implications for the modeling of hydrocarbon chemistry in the interstellar medium and the atmospheres of planets and satellites as well as in laboratory plasmas (e.g., plasma-enhanced chemical vapor deposition of carbon nanotubes and diamond-like carbon films).
Collapse
Affiliation(s)
- Vincent Richardson
- Department of Physics, University of Trento, 38123 Trento, Italy; (V.R.); (P.T.)
- Department of Physics, University of Liverpool, Oxford Street, Liverpool L69 7ZE, UK
| | - Miroslav Polášek
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejšškova 2155/3, 182 23 Prague, Czech Republic; (M.P.); (J.Ž.)
| | - Claire Romanzin
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France; (C.R.); (R.T.); (C.A.)
- Synchrotron Soleil, L’Orme des Merisiers, 91190 Saint-Aubin, France
| | - Paolo Tosi
- Department of Physics, University of Trento, 38123 Trento, Italy; (V.R.); (P.T.)
| | - Roland Thissen
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France; (C.R.); (R.T.); (C.A.)
- Synchrotron Soleil, L’Orme des Merisiers, 91190 Saint-Aubin, France
| | - Christian Alcaraz
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France; (C.R.); (R.T.); (C.A.)
- Synchrotron Soleil, L’Orme des Merisiers, 91190 Saint-Aubin, France
| | - Ján Žabka
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejšškova 2155/3, 182 23 Prague, Czech Republic; (M.P.); (J.Ž.)
| | - Daniela Ascenzi
- Department of Physics, University of Trento, 38123 Trento, Italy; (V.R.); (P.T.)
| |
Collapse
|
2
|
Zirnstein EJ, Möbius E, Zhang M, Bower J, Elliott HA, McComas DJ, Pogorelov NV, Swaczyna P. In Situ Observations of Interstellar Pickup Ions from 1 au to the Outer Heliosphere. SPACE SCIENCE REVIEWS 2022; 218:28. [PMID: 35574273 PMCID: PMC9085710 DOI: 10.1007/s11214-022-00895-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/18/2022] [Indexed: 05/08/2023]
Abstract
Interstellar pickup ions are an ubiquitous and thermodynamically important component of the solar wind plasma in the heliosphere. These PUIs are born from the ionization of the interstellar neutral gas, consisting of hydrogen, helium, and trace amounts of heavier elements, in the solar wind as the heliosphere moves through the local interstellar medium. As cold interstellar neutral atoms become ionized, they form an energetic ring beam distribution comoving with the solar wind. Subsequent scattering in pitch angle by intrinsic and self-generated turbulence and their advection with the radially expanding solar wind leads to the formation of a filled-shell PUI distribution, whose density and pressure relative to the thermal solar wind ions grows with distance from the Sun. This paper reviews the history of in situ measurements of interstellar PUIs in the heliosphere. Starting with the first detection in the 1980s, interstellar PUIs were identified by their highly nonthermal distribution with a cutoff at twice the solar wind speed. Measurements of the PUI distribution shell cutoff and the He focusing cone, a downwind region of increased density formed by the solar gravity, have helped characterize the properties of the interstellar gas from near-Earth vantage points. The preferential heating of interstellar PUIs compared to the core solar wind has become evident in the existence of suprathermal PUI tails, the nonadiabatic cooling index of the PUI distribution, and PUIs' mediation of interplanetary shocks. Unlike the Voyager and Pioneer spacecraft, New Horizon's Solar Wind Around Pluto (SWAP) instrument is taking the only direct measurements of interstellar PUIs in the outer heliosphere, currently out to ∼ 47 au from the Sun or halfway to the heliospheric termination shock.
Collapse
Affiliation(s)
- E. J. Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 USA
| | - E. Möbius
- Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 USA
| | - M. Zhang
- Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 USA
| | - J. Bower
- Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 USA
| | - H. A. Elliott
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX 78228 USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249 USA
| | - D. J. McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 USA
| | - N. V. Pogorelov
- Department of Space Science, The University of Alabama in Huntsville, Huntsville, AL 35805 USA
- Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35805 USA
| | - P. Swaczyna
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 USA
| |
Collapse
|
3
|
Kollmann P, Hill ME, Allen RC, McNutt RL, Brown LE, Barnes NP, Delamere P, Clark G, Andrews GB, Salazar N, Westlake J, Romeo G, Vandegriff J, Kusterer M, Smith D, Nelson K, Jaskulek S, Decker RB, Cheng AF, Krimigis SM, Lisse CM, Mitchell DG, Weaver HA, Elliott HA, Fattig E, Gladstone GR, Valek PW, Weidner S, Kammer J, Bagenal F, Horanyi M, Kaufmann D, Harch A, Olkin CB, Piquette MR, Spencer JR, Young LA, Ennico K, Summers ME, Stern SA. Pluto's Interaction With Energetic Heliospheric Ions. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2019; 124:7413-7424. [PMID: 35860291 PMCID: PMC9285724 DOI: 10.1029/2019ja026830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 06/15/2023]
Abstract
Pluto energies of a few kiloelectron volts and suprathermal ions with tens of kiloelectron volts and above. We measure this population using the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument on board the New Horizons spacecraft that flew by Pluto in 2015. Even though the measured ions have gyroradii larger than the size of Pluto and the cross section of its magnetosphere, we find that the boundary of the magnetosphere is depleting the energetic ion intensities by about an order of magnitude close to Pluto. The intensity is increasing exponentially with distance to Pluto and reaches nominal levels of the interplanetary medium at about 190R P distance. Inside the wake of Pluto, we observe oscillations of the ion intensities with a periodicity of about 0.2 hr. We show that these can be quantitatively explained by the electric field of an ultralow-frequency wave and discuss possible physical drivers for such a field. We find no evidence for the presence of plutogenic ions in the considered energy range.
Collapse
|
4
|
|
5
|
Glassmeier KH. Interaction of the solar wind with comets: a Rosetta perspective. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:20160256. [PMID: 28554976 PMCID: PMC5454225 DOI: 10.1098/rsta.2016.0256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/12/2017] [Indexed: 05/25/2023]
Abstract
The Rosetta mission provides an unprecedented possibility to study the interaction of comets with the solar wind. As the spacecraft accompanies comet 67P/Churyumov-Gerasimenko from its very low-activity stage through its perihelion phase, the physics of mass loading is witnessed for various activity levels of the nucleus. While observations at other comets provided snapshots of the interaction region and its various plasma boundaries, Rosetta observations allow a detailed study of the temporal evolution of the innermost cometary magnetosphere. Owing to the short passage time of the solar wind through the interaction region, plasma instabilities such as ring--beam and non-gyrotropic instabilities are of less importance during the early life of the magnetosphere. Large-amplitude ultra-low-frequency (ULF) waves, the 'singing' of the comet, is probably due to a modified ion Weibel instability. This instability drives a cross-field current of implanted cometary ions unstable. The initial pick-up of these ions causes a major deflection of the solar wind protons. Proton deflection, cross-field current and the instability induce a threefold structure of the innermost interaction region with the characteristic Mach cone and Whistler wings as stationary interaction signatures as well as the ULF waves representing the dynamic aspect of the interaction.This article is part of the themed issue 'Cometary science after Rosetta'.
Collapse
Affiliation(s)
- Karl-Heinz Glassmeier
- Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig, Mendelssohnstraße 3, 38116 Braunschweig, Germany
| |
Collapse
|
6
|
Hamilton DP, Stern SA, Moore JM, Young LA. The rapid formation of Sputnik Planitia early in Pluto's history. Nature 2016; 540:97-99. [PMID: 27905411 DOI: 10.1038/nature20586] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 10/28/2016] [Indexed: 11/09/2022]
Abstract
Pluto's Sputnik Planitia is a bright, roughly circular feature that resembles a polar ice cap. It is approximately 1,000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees, almost directly opposite the side of Pluto that always faces Charon as a result of tidal locking. One explanation for its location includes the formation of a basin in a giant impact, with subsequent upwelling of a dense interior ocean. Once the basin was established, ice would naturally have accumulated there. Then, provided that the basin was a positive gravity anomaly (with or without the ocean), true polar wander could have moved the feature towards the Pluto-Charon tidal axis, on the far side of Pluto from Charon. Here we report modelling that shows that ice quickly accumulates on Pluto near latitudes of 30 degrees north and south, even in the absence of a basin, because, averaged over its orbital period, those are Pluto's coldest regions. Within a million years of Charon's formation, ice deposits on Pluto concentrate into a single cap centred near a latitude of 30 degrees, owing to the runaway albedo effect. This accumulation of ice causes a positive gravity signature that locks, as Pluto's rotation slows, to a longitude directly opposite Charon. Once locked, Charon raises a permanent tidal bulge on Pluto, which greatly enhances the gravity signature of the ice cap. Meanwhile, the weight of the ice in Sputnik Planitia causes the crust under it to slump, creating its own basin (as has happened on Earth in Greenland). Even if the feature is now a modest negative gravity anomaly, it remains locked in place because of the permanent tidal bulge raised by Charon. Any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap. Therefore, our modelling suggests that Sputnik Planitia formed shortly after Charon did and has been stable, albeit gradually losing volume, over the age of the Solar System.
Collapse
Affiliation(s)
| | | | - J M Moore
- NASA Ames, Mountain View, California, USA
| | | | | |
Collapse
|
7
|
The formation of Charon's red poles from seasonally cold-trapped volatiles. Nature 2016; 539:65-68. [PMID: 27626378 DOI: 10.1038/nature19340] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/13/2016] [Indexed: 11/09/2022]
Abstract
A unique feature of Pluto's large satellite Charon is its dark red northern polar cap. Similar colours on Pluto's surface have been attributed to tholin-like organic macromolecules produced by energetic radiation processing of hydrocarbons. The polar location on Charon implicates the temperature extremes that result from Charon's high obliquity and long seasons in the production of this material. The escape of Pluto's atmosphere provides a potential feedstock for a complex chemistry. Gas from Pluto that is transiently cold-trapped and processed at Charon's winter pole was proposed as an explanation for the dark coloration on the basis of an image of Charon's northern hemisphere, but not modelled quantitatively. Here we report images of the southern hemisphere illuminated by Pluto-shine and also images taken during the approach phase that show the northern polar cap over a range of longitudes. We model the surface thermal environment on Charon and the supply and temporary cold-trapping of material escaping from Pluto, as well as the photolytic processing of this material into more complex and less volatile molecules while cold-trapped. The model results are consistent with the proposed mechanism for producing the observed colour pattern on Charon.
Collapse
|
8
|
Gladstone GR, Stern SA, Ennico K, Olkin CB, Weaver HA, Young LA, Summers ME, Strobel DF, Hinson DP, Kammer JA, Parker AH, Steffl AJ, Linscott IR, Parker JW, Cheng AF, Slater DC, Versteeg MH, Greathouse TK, Retherford KD, Throop H, Cunningham NJ, Woods WW, Singer KN, Tsang CCC, Schindhelm E, Lisse CM, Wong ML, Yung YL, Zhu X, Curdt W, Lavvas P, Young EF, Tyler GL, Bagenal F, Grundy WM, McKinnon WB, Moore JM, Spencer JR, Andert T, Andrews J, Banks M, Bauer B, Bauman J, Barnouin OS, Bedini P, Beisser K, Beyer RA, Bhaskaran S, Binzel RP, Birath E, Bird M, Bogan DJ, Bowman A, Bray VJ, Brozovic M, Bryan C, Buckley MR, Buie MW, Buratti BJ, Bushman SS, Calloway A, Carcich B, Conard S, Conrad CA, Cook JC, Cruikshank DP, Custodio OS, Ore CMD, Deboy C, Dischner ZJB, Dumont P, Earle AM, Elliott HA, Ercol J, Ernst CM, Finley T, Flanigan SH, Fountain G, Freeze MJ, Green JL, Guo Y, Hahn M, Hamilton DP, Hamilton SA, Hanley J, Harch A, Hart HM, Hersman CB, Hill A, Hill ME, Holdridge ME, Horanyi M, Howard AD, Howett CJA, Jackman C, Jacobson RA, Jennings DE, Kang HK, Kaufmann DE, Kollmann P, Krimigis SM, Kusnierkiewicz D, Lauer TR, Lee JE, Lindstrom KL, Lunsford AW, Mallder VA, Martin N, McComas DJ, McNutt RL, Mehoke D, Mehoke T, Melin ED, Mutchler M, Nelson D, Nimmo F, Nunez JI, Ocampo A, Owen WM, Paetzold M, Page B, Pelletier F, Peterson J, Pinkine N, Piquette M, Porter SB, Protopapa S, Redfern J, Reitsema HJ, Reuter DC, Roberts JH, Robbins SJ, Rogers G, Rose D, Runyon K, Ryschkewitsch MG, Schenk P, Sepan B, Showalter MR, Soluri M, Stanbridge D, Stryk T, Szalay JR, Tapley M, Taylor A, Taylor H, Umurhan OM, Verbiscer AJ, Versteeg MH, Vincent M, Webbert R, Weidner S, Weigle GE, White OL, Whittenburg K, Williams BG, Williams K, Williams S, Zangari AM, Zirnstein E. The atmosphere of Pluto as observed by New Horizons. Science 2016; 351:aad8866. [PMID: 26989258 DOI: 10.1126/science.aad8866] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- G. Randall Gladstone
- Southwest Research Institute, San Antonio, TX 78238, USA
- University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - S. Alan Stern
- Southwest Research Institute, Boulder, CO 80302, USA
| | - Kimberly Ennico
- National Aeronautics and Space Administration, Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA
| | | | - Harold A. Weaver
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | | | | | - David P. Hinson
- Search for Extraterrestrial Intelligence Institute, Mountain View, CA 94043, USA
| | | | | | | | | | | | - Andrew F. Cheng
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | | | | | - Kurt D. Retherford
- Southwest Research Institute, San Antonio, TX 78238, USA
- University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Henry Throop
- The Johns Hopkins University, Baltimore, MD 21218, USA
| | | | | | | | | | | | - Carey M. Lisse
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | - Yuk L. Yung
- California Institute of Technology, Pasadena, CA 91125, USA
| | - Xun Zhu
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - Werner Curdt
- Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
| | - Panayotis Lavvas
- Groupe de Spectroscopie Moléculaire et Atmosphérique, Université Reims Champagne-Ardenne, 51687 Reims, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Weird and wonderful Pluto spills its secrets. Nature 2016. [DOI: 10.1038/nature.2016.19585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|