Energy Distributions in Unimolecular Reactions

1977 ◽  
Vol 81 (2) ◽  
pp. 190-197 ◽  
Author(s):  
R. A. Marcus
Keyword(s):  
Energy Distributions ◽  
Unimolecular Reactions

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.

scholarly journals Erratum: ProSpect: generating spectral energy distributions with complex star formation and metallicity histories

2020 ◽  
Vol 500 (3) ◽  
pp. 2859-2860
Author(s):  
A S G Robotham ◽  
S Bellstedt ◽  
C del P Lagos ◽  
J E Thorne ◽  
L J Davies ◽  
...  
Keyword(s):  
Star Formation ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions
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