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Kannan G, Chien JR, Benjamin AJ, Bhatia N, Saykally RJ. Rydberg States of H 3 and HeH as Potential Coolants for Primordial Star Formation. J Phys Chem A 2021; 125:4267-4275. [PMID: 33792328 DOI: 10.1021/acs.jpca.0c10983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Current theory and measurements establish the age of the universe as ca. 13.8 billion years. For the first several hundred million years of its existence, it was a dark, opaque void. After that, the hydrogen atoms comprising most of the "ordinary" matter began to condense and ionize, eventually forming the first stars that would illuminate the sky. Details of how these "primordial" stars formed have been widely debated, but remain elusive. A central issue in this process is the mechanism by which the primordial gas (mainly hydrogen and helium atoms) collected via the action of dark matter cooled and further accreted to fusion densities. Current models invoke collisional excitation of H2 molecular rotations and subsequent radiative rotational transitions allowed by the weak molecular quadrupole moment. In this work, we review the salient considerations and present some new ideas, based on recent spectroscopic observations of neutral H3 Rydberg electronic state emission in the mid-infrared region.
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Affiliation(s)
- Gokul Kannan
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Jeremy R Chien
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Anthony J Benjamin
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Niranjan Bhatia
- Monta Vista High School, 21840 McClellan Road, Cupertino, California 95014, United States
| | - Richard J Saykally
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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Dohnal P, Shapko D, Kálosi Á, Kassayová M, Roučka Š, Rednyk S, Plašil R, Hejduk M, Glosík J. Towards state selective recombination of H 3+ under astrophysically relevant conditions. Faraday Discuss 2019; 217:220-234. [PMID: 31016318 DOI: 10.1039/c8fd00214b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present studies on the thermalisation of H3+ ions in a cold He/Ar/H2 plasma at temperatures 30-70 K. We show that we are able to generate a rotationally thermalised H3+ ensemble with a population of rotational and nuclear spin states corresponding to a particular ion translational temperature. By varying the para-H2 fraction used in the experiment we are able to produce para-H3+ ions with fractional populations higher than those corresponding to thermodynamic values. At 35 K, only the lowest rotational states of para and ortho H3+ are populated. This is the first step towards experimental studies of electron-molecular ion recombination processes with precisely specified quantum states at astrophysically relevant temperatures.
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Affiliation(s)
- Petr Dohnal
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Dmytro Shapko
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Ábel Kálosi
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Miroslava Kassayová
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Štěpán Roučka
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Serhiy Rednyk
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Radek Plašil
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
| | - Michal Hejduk
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK
| | - Juraj Glosík
- Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University, V Holešovičkách 2, 180 00 Praha 8-Libeň, Czech Republic.
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Plašil R, Dohnal P, Kálosi Á, Roučka Š, Shapko D, Rednyk S, Johnsen R, Glosík J. Stationary afterglow apparatus with CRDS for study of processes in plasmas from 300 K down to 30 K. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:063116. [PMID: 29960549 DOI: 10.1063/1.5036834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A cryogenic stationary afterglow apparatus equipped with a near-infrared cavity-ring-down-spectrometer (Cryo-SA-CRDS) for studies of electron-ion recombination processes in the plasma at temperatures 30-300 K has been designed, constructed, tested, and put into operation. The plasma is generated in a sapphire discharge tube that is contained in a microwave cavity. The cavity and the tube are attached to the second stage of the cold head of the cryocooler system, and they are inserted to an UHV chamber with mirrors for CRDS and vacuum windows on both ends of the tube. The temperature of the discharge tube can be made as low as 25 K. In initial test measurements, the discharge was ignited in He/Ar/H2 or He/H2 gas mixtures and the density of H3+ ions and their kinetic and rotational temperatures were measured during the discharge and afterglow. From the measured decrease in the ion density, during the afterglow, effective recombination rate coefficients were determined. Plasma relaxation was studied in He/Ar gas mixtures by monitoring the presence of highly excited argon atoms. The spectroscopic measurements demonstrated that the kinetic temperature of the ions is equal to the gas temperature and that it can be varied from 300 K down to 30 K.
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Affiliation(s)
- R Plašil
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - P Dohnal
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Á Kálosi
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Š Roučka
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - D Shapko
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - S Rednyk
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - R Johnsen
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - J Glosík
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
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Dohnal P, Kálosi Á, Plašil R, Roučka Š, Kovalenko A, Rednyk S, Johnsen R, Glosík J. Binary and ternary recombination of H2D+ and HD2+ ions with electrons at 80 K. Phys Chem Chem Phys 2016; 18:23549-53. [DOI: 10.1039/c6cp04152c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The recombination of deuterated trihydrogen cations with electrons was studied at 80 K using stationary afterglow with cavity ring-down spectroscopy.
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Affiliation(s)
- Petr Dohnal
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
| | - Ábel Kálosi
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
| | - Radek Plašil
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
| | - Štěpán Roučka
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
| | - Artem Kovalenko
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
| | - Serhiy Rednyk
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
| | - Rainer Johnsen
- Department of Physics and Astronomy
- University of Pittsburgh
- Pittsburgh
- USA
| | - Juraj Glosík
- Department of Surface and Plasma Science
- Faculty of Mathematics and Physics
- Charles University in Prague
- Prague
- Czech Republic
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