Electroionization study of ethylene: structures in the ionization and appearance curves

1987 ◽  
Vol 65 (7) ◽  
pp. 803-807 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Carbon Atom ◽  
High Signal ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Text Production ◽  
Text Fragment ◽  
First Time ◽  
Fragmentation Processes ◽  
Fragment Production ◽  
Very High

Ionization-efficiency curves with very high signal-to-noise ratios for ethylene and all fragments consisting of at least one carbon atom are presented and analyzed. The curves are produced by monoenergetic electron impact and extend up to 10 eV above threshold. Most of the structures observed thus far by this method for these regions are reported here for the first time. Competition between [Formula: see text] production and [Formula: see text] and [Formula: see text] fragment production is clearly seen in the respective curves. Features occurring at the same energy in several of the curves indicate that these are due to a common progenitor, particularly the [Formula: see text] complex. The appearance of different fragmentation processes accounts for the onset-type structure found in some of the fragment-ion curves.

scholarly journals Electroionization study of ethane: structures in the ionization and appearance curves

1987 ◽  
Vol 65 (9) ◽  
pp. 2004-2008 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Carbon Atom ◽  
Signal To Noise Ratio ◽  
Negative Ion ◽  
High Signal ◽  
Feshbach Resonances ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Fragment Ions ◽  
Novel Structures ◽  
Very High

Ionization efficiency curves of very high signal-to-noise ratio are presented for ethane and most fragment ions containing at least one carbon atom. These curves, which are produced by monoenergetic electron impact, extend up to 10 eV above the initial onsets. Novel structures are observed in most curves. Certain features appear at the same energy in several of the curves indicating that they belong to a common progenitor, either [Formula: see text] or [Formula: see text], and not directly to the detected ions. These sets of structure are attributed to negative ion states (Feshbach resonances) and/or to Rydberg autoionizing states.

Electroionization study of ethylene: ionization and appearance energies, ion-pair formations, and negative ions

1987 ◽  
Vol 65 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Electron Impact ◽  
Negative Ions ◽  
High Sensitivity ◽  
Ion Pair ◽  
Common Mechanism ◽  
Threshold Region ◽  
Monoenergetic Electron ◽  
Text Fragment ◽  
First Time ◽  
Very High

Monoenergetic electron-impact threshold ionization and appearance curves of very high sensitivity of ethylene and all fragments containing at least one carbon atom are analyzed in detail. Ionization or appearance energies are measured for all ions, including the [Formula: see text] fragment. Structures are observed in the immediate [Formula: see text] threshold region, which are attributed to hot bands and to Rydberg autoionizing states. [Formula: see text],[Formula: see text] and [Formula: see text] ion-pair formations are reported for the first time. Simultaneous production of positive and negative ions is seen to be a common mechanism by electron impact. Appearance energies of some fragments are several electron volts lower than those of previous works.

A Study of the Orbital and Intrinsic Variability of the Double-Lined Spectroscopic Binary β Centauri

2002 ◽  
Vol 185 ◽  
pp. 86-87
Author(s):  
M. Ausseloos ◽  
C. Aerts ◽  
K. Uytterhoeven
Keyword(s):  
High Resolution ◽  
Orbital Motion ◽  
High Signal ◽  
Mass Ratio ◽  
Eccentric Orbit ◽  
Intrinsic Variability ◽  
Signal To Noise ◽  
Orbital Parameters ◽  
Spectroscopic Binary ◽  
First Time

AbstractWe introduce our observational study of the orbital motion of β Cen. Using 463 high signal-to-noise, high-resolution spectra obtained over a timespan of 12 years it is shown that the radial velocity of β Cen varies with an orbital period of 357.0 days. We derive for the first time the orbital parameters of β Cen and find a very eccentric orbit (e = 0.81) and similar component masses with a mass ratio M1/M2 = 1.02. Both the primary and the secondary exhibit periodic line-profile variations.

Molybdenum carbide chemical sensors with ultrahigh signal-to-noise ratios and ambient stability

2018 ◽  
Vol 6 (46) ◽  
pp. 23408-23416 ◽  
Author(s):  
Soo-Yeon Cho ◽  
Ju Ye Kim ◽  
Ohmin Kwon ◽  
Jihan Kim ◽  
Hee-Tae Jung
Keyword(s):  
Chemical Sensors ◽  
Molybdenum Carbide ◽  
Gas Sensing ◽  
High Signal ◽  
Signal To Noise ◽  
Molybdenum Carbides ◽  
First Time ◽  
Sensing Performance

In this study, we investigate the gas sensing performance of molybdenum carbides for the first time and they show ultra-high signal-to-noise ratios and excellent ambient stability.

scholarly journals The well correlated diffuse interstellar bands at λλ 6196, 6614 Å and their possible companions

2020 ◽  
Vol 496 (2) ◽  
pp. 2231-2240
Author(s):  
A Bondar
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
High Resolution ◽  
Aromatic Hydrocarbons ◽  
Correlation Coefficients ◽  
High Signal ◽  
Signal To Noise ◽  
B Stars ◽  
Diffuse Interstellar Bands ◽  
Polycyclic Aromatic ◽  
First Time

ABSTRACT Considered here is the interrelation between five diffuse interstellar bands (DIBs), λλ 5545, 6113, 6196, 6445 and 6614 Å. Two DIBs (λλ 6196 and 6614 Å) are already known as being well correlated with each other; their relation with three other weaker bands is investigated for the first time. To accomplish this task, high-resolution spectra (λ/δλ ≈100 000) with high signal-to-noise ratios (S/N) of 54 hot O–B stars with reddening 0.12–1.45 mag were used. Analysis of measured equivalent widths has allowed us to establish linear dependences and evaluate linear correlation coefficients as high as 0.968–0.988 between the intensities of these five DIBs. Such a degree of correlation may indicate their common origin. Several spacings in wavenumbers found between these DIBs correspond to the energies of vibrational transitions in some polycyclic aromatic hydrocarbons resulting in IR emissions at λλ 16.4, 11.3, 7.7, 6.2 and 3.3 μm.

scholarly journals NGC 6302: high-ionization permitted lines. Applying X-SSN synthesis to VLT-UVES spectra

2011 ◽  
Vol 7 (S283) ◽  
pp. 470-471
Author(s):  
Daniel Péquignot ◽  
Christophe Morisset ◽  
Simon Casassus
Keyword(s):  
High Signal ◽  
Signal To Noise ◽  
High Ionization ◽  
Spectrum Synthesis ◽  
First Time

AbstractA preliminary VLT-UVES spectrum of NGC 6302 (Casassus et al. 2002, MN), which hosts one of the hottest PN nuclei known (Teff ~ 220000 K; Wright et al. 2011, MN), has been recently analysed by means of X-SSN, a spectrum synthesis code for nebulae (Morisset and Péquignot). Permitted recombination lines from highly-ionized species are detected/identified for the first time in a PN, and some of them probably for the first time in (astro)physics. The need for a homogeneous, high signal-to-noise UVES spectrum for NGC 6302 is advocated.

Anti-Vibration Sub Allows A Very High Signal-To-Noise Ratio And Improves Borehole Quality

2013 ◽  
Author(s):  
Paul Christian Bates ◽  
Chakib Bouziane ◽  
Denise Nicholl ◽  
Reina Teelken ◽  
Mohammed Zuki Bin Bidi ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Very High

scholarly journals Doppler Imaging of Starspots

1983 ◽  
Vol 71 ◽  
pp. 379-385
Author(s):  
Steven S. Vogt ◽  
G. Donald Penrod
Keyword(s):  
Doppler Imaging ◽  
Stellar Disk ◽  
Doppler Velocity ◽  
High Signal ◽  
Line Profiles ◽  
Signal To Noise ◽  
Rs Cvn Stars ◽  
Spot Model ◽  
Very High ◽  
General Appearance

ABSTRACTWe discuss a newly-developed technique for spatially resolving starspots on some of the more rapidly rotating RS CVn stars. Basically, the method uses high resolution, very high signal-to-noise spectral line profiles and exploits the Doppler velocity correspondence between position across the stellar disk and wavelength position across a rotationally broadened line profile to synthesize an image of the star, showing the location, sizes, and shapes of its starspots. Though still in a developmental stage, the technique is already yielding information about the structure and general appearance of starspots. Examples of Doppler Imaging observations of HR 1099 will be presented, along with a movie showing the behavior of synthetic line profiles generated from a computer spot model.

scholarly journals A Precise CN Measurement of the Microwave Background at 1.32 mm

1990 ◽  
Vol 139 ◽  
pp. 392-393
Author(s):  
David M. Meyer ◽  
Katherine C. Roth ◽  
Isabel Hawkins
Keyword(s):  
Cosmic Microwave Background ◽  
Brightness Temperature ◽  
High Signal ◽  
Microwave Background ◽  
Signal To Noise ◽  
Upper Limit ◽  
Vibrational Bands ◽  
Very High ◽  
Cmb Temperature ◽  
Line Strengths

We present very high signal-to-noise observations of the (1,0) and (0,0) vibrational bands of interstellar CN near 3580 and 3874 Å toward HD 21483. Corrected for saturation with a derived b-value of 1.29±0.05 km s-1, these CN line strengths yield excitation temperatures of 2.83±0.09 and 2.76±0.07 K for the J=1-2 and J=0-1 rotational transitions at 1.32 and 2.64 mm. In the absence of local CN excitation, these values represent the brightness temperature of the cosmic microwave background (CMB) radiation at these wavelengths. Millimeter observations have revealed no CN emission at 2.64 mm toward HD 21483 and allow us to set a 2σ upper limit of 0.11 K on the contribution of local processes to the J=0-1 excitation. Considering this limit and the lesser likelihood of local J=1-2 excitation, our observations indicate a CMB temperature of 2.83±0.09 K at 1.32 mm.

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