Energy distributions of oxygen ions desorbed from CO- and NO-covered nickel

1993 ◽  
Vol 287-288 ◽  
pp. A366
Author(s):  
A. Takano ◽  
K. Ueda
Keyword(s):  
Energy Distributions ◽  
Oxygen Ions

scholarly journals Invariants of the Spatial-Energy Structure and Modeling of the Earth's Ion Radiation Belts

2019 ◽  
Author(s):  
Alexander S. Kovtyukh
Keyword(s):  
Radiation Belts ◽  
Ion Fluxes ◽  
Energy Structure ◽  
Energy Distributions ◽  
Oxygen Ions ◽  
Space Flights ◽  
Physical Mechanisms ◽  
Proton Fluxes ◽  
White Spots ◽  
First Time

Abstract. The spatial-energy distributions of proton fluxes in the Earth's radiation belts (ERB) are well studied and the NASA averaged empirical models constructed for them (the latest versions are AP8 and AP9). These models are widely used in space research. However, for heavier ERB ions (helium, oxygen, etc.), much less measurements were made on satellites, especially in the energy range from tens to hundreds of MeV, and there are no sufficiently complete and reliable models for them. Meanwhile, such ions, although there are much smaller than protons, play a very important role in the physics of ERB, especially in their dynamics, as well as in solving problems of ensuring the safety of space flights. The data on such ions represent a rather fragmentary picture, in which there are significant white spots. Using the methods considered in this paper, these fragmentary data can be streamlined, linked to each other and get a regular picture that has a simple physical meaning. Spatial-energy distributions of the stationary fluxes of protons, helium ions and ions of the CNO group with energy from 100 keV to 200 MeV at L ~ 1–8 considered here on the data of the satellites for 1961–2017. It is found, that results of the measurements of the ion fluxes are arrange in certain regular patterns in the spaces {E, L} and {L, B/B0}. This effect connected with the existence of invariant parameters of these distributions of ion fluxes. These invariant parameters are very useful and necessary for constructing the ion models of the ERB. The physical mechanisms leading to formation spatial-energy structure of the ERB ion fluxes and the values of its invariant parameters discussed here. In the course of this work, solar-cyclic (11-year) variations in the distributions of helium and carbon-nitrogen-oxygen ions fluxes in the ERB studied for the first time. It shown that, as compared with such variations in the proton fluxes studied earlier, the amplitude of the variations of heavier ions is much larger and increases with increasing their mass.

Scattering of Low-Energy (5-12 eV) C2D4•+ Ions from Room-Temperature Carbon Surfaces

2008 ◽  
Vol 73 (6-7) ◽  
pp. 755-770 ◽  
Author(s):  
Andriy Pysanenko ◽  
Ján Žabka ◽  
Zdeněk Herman
Keyword(s):  
Survival Probability ◽  
Room Temperature ◽  
Incident Angle ◽  
Pyrolytic Graphite ◽  
Carbon Surface ◽  
Translational Energy ◽  
Energy Distributions ◽  
Surface Mass ◽  
Fragment Ions ◽  
Product Ions

The scattering of the hydrocarbon radical cation C2D4•+ from room-temperature carbon (highly oriented pyrolytic graphite, HOPG) surface was investigated at low incident energies of 6-12 eV. Mass spectra, angular and translational energy distributions of product ions were measured. From these data, information on processes at surfaces, absolute ion survival probability, and kinematics of the collision was obtained. The projectile ion showed both inelastic, dissociative and reactive scattering, namely the occurrence of H-atom transfer reaction with hydrocarbons present on the room-temperature carbon surface. The absolute survival probability of the ions for the incident angle of 30° (with respect to the surface) decreased from about 1.0% (16 eV) towards zero at incident energies below 10 eV. Estimation of the effective surface mass involved in the collision process led to m(S)eff of about 57 a.m.u. for inelastic non-dissociative collisions of C2D4•+ and of about 115 a.m.u. for fragment ions (C2D3+, C2D2•+) and ions formed in reactive surface collisions (C2D4H+, C2D2H+, contributions to C2D3+ and C2D2•+). This suggested a rather complex interaction between the projectile ion and the hydrocarbon-covered surface during the collision.

Charge Transfer Between CO22+ and Ar or Ne at Collision Energies 3-10 eV

2003 ◽  
Vol 68 (1) ◽  
pp. 178-188 ◽  
Author(s):  
Libor Mrázek ◽  
Ján Žabka ◽  
Zdeněk Dolejšek ◽  
Zdeněk Herman
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ground State ◽  
Scattering Method ◽  
Translational Energy ◽  
Centre Of Mass ◽  
Energy Distributions ◽  
Zener Model ◽  
Beam Scattering ◽  
Product Ions

The beam scattering method was used to investigate non-dissociative single-electron charge transfer between the molecular dication CO22+ and Ar or Ne at several collision energies between 3-10 eV (centre-of-mass, c.m.). Relative translational energy distributions of the product ions showed that in the reaction with Ar the CO2+ product was mainly formed in reactions of the ground state of the dication, CO22+(X3Σg-), leading to the excited states of the product CO2+(A2Πu) and CO2+(B2Σu+). In the reaction with Ne, the largest probability had the process from the reactant dication excited state CO22+(1Σg+) leading to the product ion ground state CO2+(X2Πg). Less probable were processes between the other excited states of the dication CO22+, (1∆g), (1Σu-), (3∆u), also leading to the product ion ground state CO2+(X2Πg). Using the Landau-Zener model of the reaction window, relative populations of the ground and excited states of the dication CO22+ in the reactant beam were roughly estimated as (X3Σg):(1∆g):(1Σg+):(1Σu-):(3∆u) = 1.0:0.6:0.5:0.25:0.25.

scholarly journals Characterization of M dwarfs using optical mid-resolution spectra for exploration of small exoplanets

2020 ◽  
Author(s):  
Yohei Koizumi ◽  
Masayuki Kuzuhara ◽  
Masashi Omiya ◽  
Teruyuki Hirano ◽  
John Wisniewski ◽  
...  
Keyword(s):  
Sample Selection ◽  
Optical Spectra ◽  
Average Error ◽  
Spectral Energy ◽  
M Dwarfs ◽  
Energy Distributions ◽  
Fitting Procedures ◽  
Optical Region ◽  
Selection For

Abstract We present the optical spectra of 338 nearby M dwarfs, and compute their spectral types, effective temperatures (Teff), and radii. Our spectra were obtained using several optical spectrometers with spectral resolutions that range from 1200 to 10000. As many as 97% of the observed M-type dwarfs have a spectral type of M3–M6, with a typical error of 0.4 subtype, among which the spectral types M4–M5 are the most common. We infer the Teff of our sample by fitting our spectra with theoretical spectra from the PHOENIX model. Our inferred Teff is calibrated with the optical spectra of M dwarfs whose Teff have been well determined with the calibrations that are supported by previous interferometric observations. Our fitting procedures utilize the VO absorption band (7320–7570 Å) and the optical region (5000–8000 Å), yielding typical errors of 128 K (VO band) and 85 K (optical region). We also determine the radii of our sample from their spectral energy distributions. We find most of our sample stars have radii of <0.6 R⊙, with the average error being 3%. Our catalog enables efficient sample selection for exoplanet surveys around nearby M-type dwarfs.

scholarly journals Liquid-Mirror Telescope Surveys

1998 ◽  
Vol 11 (1) ◽  
pp. 464-467
Author(s):  
P. Hickson
Keyword(s):  
Integration Time ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Ccd Cameras ◽  
Photometric Redshifts ◽  
Rotating Liquid ◽  
Liquid Mirrors ◽  
Under Construction ◽  
Optical Telescopes ◽  
Mirror Telescope

Abstract Recent advances in the technology of rotating liquid-mirrors now make feasible the construction of large optical telescopes for dedicated survey programs. Two three-metre-class astronomical telescopes have been built and asix-metre telescope is under construction. These instruments observe in zenith-pointing mode, using drift-scanning CCD cameras to record continuous imaging of a strip of sky typically 20 arcmin wide. This enables them to observe of order 100 square degrees of sky with an integration time of a few minutes per night. Data can be co-added from night to night in order to increase the depth of the survey. Liquid-mirror telescopes are particularly wellsuited to surveys using broad or intermediate bandwidth filters to obtain photometric redshifts and spectral energy distributions for faint galaxies and quasars.

Sign in / Sign up

Export Citation Format

Share Document