The Rate of Ionization of Some Aromatic Hydrocarbons in Ethanolic Dimethyl Sulfoxide

1974 ◽  
Vol 52 (7) ◽  
pp. 1059-1061 ◽  
Author(s):  
A. Albagli ◽  
J. R. Jones ◽  
Ross Stewart
Keyword(s):  
Dimethyl Sulfoxide ◽  
Aromatic Hydrocarbons ◽  
Sodium Ethoxide ◽  
Ionization Rate ◽  
Unit Slope ◽  
Straight Line ◽  
Ionization Rates

The rates of detritiation of triphenlymethane, 9-phenylxanthene, fluorene, 9-ethylfluorene, 9-phenylfiuorene, and 2,3-benzofluorene have been measured in ethanolic dimethyl sulfoxide (DMSO) containing sodium ethoxide. When the logarithm of the ionization rate is plotted against the logarithm of the ionization rate of DMSO a straight line of near-to-unit slope is obtained in each case. There are significant differences, however, between relative ionization rates and equilibrium acidities.

Tunneling Ionization Study of Linear Molecules in Strong-Field Laser Pulses

2020 ◽  
Vol 65 (1-2) ◽  
pp. 57-68
Author(s):  
V. Petrović ◽  
◽  
H. Delibašić ◽  
I. Petrović ◽  
◽  
...  
Keyword(s):  
Ionization Potential ◽  
Strong Field ◽  
Laser Pulses ◽  
Ionization Rate ◽  
Rate Equations ◽  
Tunneling Ionization ◽  
Low Intensity ◽  
Linear Molecules ◽  
Experimental Findings ◽  
Ionization Rates

"We theoretically studied photoionization of atoms and molecules in the frame of Perelomov-Popov-Terent’ev (PPT) and Ammosov-Delone-Krainov (ADK) theories. Strong-field single ionization of two diatomic molecules, N_2 and O_2, are studied and compared to Ar and Xe atoms, using an 800 nm Ti:sapphire laser in the 3×〖10〗^13 to 1×〖10〗^15 Wcm^(-2) intensity range. To eliminate disagreement between theoretical and experimental findings in a low intensity fields (~6×〖10〗^13 Wcm^(-2)), we considered the influence of shifted ionization potential. Including these effects in the ionization rates, we numerically solved rate equations in order to determine an expression for the ionization yields. The use of modified ionization potential showed that the ionization yields will actually decrease below values predicted by original (uncorrected) formulas. This paper will discuss the causes of this discrepancy. Keywords: tunneling ionization, ionization rate, ionization yield, molecules. "

scholarly journals The glow duration time influence on the ionization rate detected in the diodes filled with noble gases on mbar pressures

2003 ◽  
Vol 2 (5) ◽  
pp. 259-267 ◽  
Author(s):  
Olivera Stepanovic ◽  
Miodrag Radovic ◽  
Cedomir Maluckov
Keyword(s):  
Electrical Breakdown ◽  
Measuring Method ◽  
Stationary Regime ◽  
Ionization Rate ◽  
Relaxation Period ◽  
Breakdown Time ◽  
Duration Time ◽  
Current Duration ◽  
Helium Neon ◽  
Ionization Rates

The results of the glow current duration time (glowing-time) influence on the ionization rate detected in the gas filled diodes are presented. The electrical breakdown was detected as the minimal current impulse. After that diode glow from the minimal glowing-time (10-3 s), up to the maximal 103 s which overlap the time of the stationary regime formation in the gas diode tube. The diodes were with volumes of 300 cm3, but with a diode gap volume of about 1 cm3 and filled with helium, neon, argon or krypton, at the pressures of the order of mbar. The ionization rates were detected as the residual ionization after the glowing was interrupted, using the electrical breakdown time delay measuring method. The influence of the gap distance stationary current values and the relaxation period were also investigated. The result shows that the stationary regime in such a gas diode is established after the glowing time of 1-3 s, although the breakdown formative times were smaller then 1 ms.

scholarly journals On the Cosmic Ray-Induced Ionization Rate in Molecular Clouds

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Ararat G. Yeghikyan
Keyword(s):  
Molecular Clouds ◽  
Column Density ◽  
Cosmic Ray ◽  
Ionization Rate ◽  
Electronic Interaction ◽  
Absorbing Medium ◽  
Be Star ◽  
Good Agreement ◽  
Ionization Rates

The transformation of the energy dependence of the cosmic ray proton flux in the keV to GeV region is investigated theoretically when penetrating inside molecular clouds ( mag). The computations suggest that energy losses of the cosmic ray particles by interaction with the matter of the molecular cloud are principally caused by the inelastic (electronic) interaction potential; the transformed energy distribution of energetic protons is determined mainly by the column density of the absorbing medium. A cutoff of the cosmic ray spectrum inside clouds by their magnetic fields is also phenomenologically taken into account. This procedure allows a determination of environment-dependent ionization rates of molecular clouds. The theoretically predicted ionization rates are in good agreement with those derived from astronomical observations of absorption lines in the spectrum of the cloud connected with the Herbig Be star LkH 101.

Mechanistic Information on the Aquations of Complexes of the Pentaamminecobalt(III) Series from Kinetic Studies at High Pressures

1972 ◽  
Vol 50 (17) ◽  
pp. 2739-2746 ◽  
Author(s):  
W. E. Jones ◽  
L. R. Carey ◽  
T. W. Swaddle
Keyword(s):  
High Pressures ◽  
Rate Coefficient ◽  
Kinetic Studies ◽  
Quadratic Equation ◽  
Water Molecules ◽  
First Order ◽  
Unit Slope ◽  
Straight Line ◽  
The Mean ◽  
The Stability

The logarithm of the pseudo-first-order rate coefficient k for the aquation of Co(NH3)5X(3–n)+ can be represented by a quadratic equation in the pressure P, or, better, by[Formula: see text]where P is in kbar, [Formula: see text] is the volume of activation at P = 0, and x is the increase in the number of water molecules solvating the complex as it goes to the transition state. For [Formula: see text]Cl−, Br−,[Formula: see text] and [Formula: see text] at 25° [Formula: see text] and ionic strength I = 0.1 M LiClO4/HClO4, [Formula: see text] −10.6, −9.2, −6.3, and +16.8 cm3 mol−1, and x = 8.0, 4.1, 3.9, 1.9, and −4.2; for Xn− = NCS−, the mean ΔV* from P = 0.001 to 2.5 kbar at 88° is −4 cm3 mol−1. Detailed consideration of these data, especially their correlation with the molar volume of reaction by a straight line of unit slope for [Formula: see text] Cl−, Br−, NO3−, and H2O, provides strong evidence for a dissociative interchange mechanism. For [Formula: see text] the separating entity is probably HN3 rather than [Formula: see text] For Xn− = NCS−, aquation is incomplete, at practical complex concentrations; at 88.0°, 1 bar, and I = 0.1 M LiClO4/HClO4, k = 3.3 × 10−6 s−1 and the stability constant of Co(NH3)5NCS2+ is 490 M−1.

scholarly journals HEPPA III intercomparison experiment on electron precipitation impacts:  Estimated ionization rates during a geomagnetic active period in April 2010

2021 ◽  
Author(s):  
Hilde Nesse Tyssøy ◽  
Miriam Sinnhuber ◽  
Timo Asikainen ◽  
Stefan Bender ◽  
Mark A. Clilverd ◽  
...  
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Ionization Rate ◽  
Data Sets ◽  
Active Period ◽  
Medium Energy ◽  
Model Driven ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Ionization Rates

<p>Precipitating auroral and radiation belt electrons are considered an important part of the natural forcing of the climate system.  Recent studies suggest that this forcing is underestimated in current chemistry-climate models. The HEPPA III intercomparison experiment is a collective effort to address this point. Here, eight different estimates of medium energy electron (MEE) (>30 keV) ionization rates are assessed during a geomagnetic active period in April 2010.  The objective is to understand the potential uncertainty related to the MEE energy input. The ionization rates are all based on the Medium Energy Proton and Electron Detector (MEPED) on board the NOAA/POES and EUMETSAT/MetOp spacecraft series. However, different data handling, ionization rate calculations, and background atmospheres result in a wide range of mesospheric electron ionization rates. Although the eight data sets agree well in terms of the temporal variability, they differ by about an order of magnitude in ionization rate strength both during geomagnetic quiet and disturbed periods. The largest spread is found in the aftermath of the geomagnetic activity.  Furthermore, governed by different energy limits, the atmospheric penetration depth varies, and some differences related to latitudinal coverage are also evident. The mesospheric NO densities simulated with the Whole Atmospheric Community Climate Model driven by highest and lowest ionization rates differ by more than a factor of eight. In a follow-up study, the atmospheric responses are simulated in four chemistry-climate models and compared to satellite observations, considering both the model structure and the ionization forcing.</p>

scholarly journals Long-term observations of positive cluster ion concentration, sources and sinks at the high altitude site of the Puy de Dôme

2013 ◽  
Vol 13 (6) ◽  
pp. 14927-14975 ◽  
Author(s):  
C. Rose ◽  
J. Boulon ◽  
M. Hervo ◽  
H. Holmgren ◽  
E. Asmi ◽  
...  
Keyword(s):  
Steady State ◽  
High Altitude ◽  
Balance Equation ◽  
Ionization Rate ◽  
Particle Formation ◽  
Ion Concentration ◽  
Cluster Ions ◽  
New Particle Formation ◽  
Cluster Ion ◽  
Ionization Rates

Abstract. Cluster particles (0.8–1.9 nm) are key entities involved in nucleation and new particle formation processes in the atmosphere. Cluster ions were characterized in clear sky conditions at the Puy de Dôme station (1465 m a.s.l). The studied dataset spread over five years (February 2007–February 2012), which provided a unique chance to catch seasonal variations of cluster ion properties at high altitude. Statistical values of the cluster ion concentration and diameter are reported for both positive and negative polarities. Cluster ions were found to be ubiquitous at the Puy de Dôme and displayed an annual variation with lower concentrations in spring. Positive cluster ions were less numerous than negative ones but were larger in diameters. Negative cluster ion properties seemed insensitive to the occurrence of a new particle formation (NPF) event while positive cluster ions appeared to be significantly more numerous and larger on event days. The parameters of the balance equation for the positive cluster concentration are reported, separately for the different seasons and for the NPF event days and non-event days. The steady state assumption suggests that the ionization rate is balanced with two sinks which are the ion recombination and the attachment on aerosol particles, referred as "aerosol ion sink". The aerosol ion sink was found to be higher during the warm season and dominated the loss of ions. The positive ionization rates derived from the balance equation were well correlated with the ionization rates obtained from radon measurement, and they were on average higher in summer and fall compared to winter and spring. Neither the aerosol ion sink nor the ionization rate were found to be significantly different on event days compared to non-event days, and thus they were not able to explain the different positive cluster concentrations between event and non-event days. Hence, the excess of positive small ions on event days may derive from an additional source of ions coupled with the fact that the steady state was not verified on event days.

scholarly journals Complex cyanides as chemical clocks in hot cores

2018 ◽  
Vol 616 ◽  
pp. A67 ◽  
Author(s):  
V. Allen ◽  
F. F. S. van der Tak ◽  
C. Walsh
Keyword(s):  
Cosmic Ray ◽  
Ionization Rate ◽  
High Mass ◽  
Small Scale ◽  
Mass Star ◽  
Chemical Difference ◽  
Gas Density ◽  
Warm Up ◽  
Dust Temperature ◽  
Ionization Rates

Context. In the high-mass star-forming region G35.20−0.74N, small scale (~800 AU) chemical segregation has been observed in which complex organic molecules containing the CN group are located in a small location (toward continuum peak B3) within an apparently coherently rotating structure. Aims. We aim to determine the physical origin of the large abundance difference (~4 orders of magnitude) in complex cyanides within G35.20−0.74 B, and we explore variations in age, gas/dust temperature, and gas density. Methods. We performed gas-grain astrochemical modeling experiments with exponentially increasing (coupled) gas and dust temperature rising from 10 to 500 K at constant H2 densities of 107 cm−3, 108 cm−3, and 109 cm−3. We tested the effect of varying the initial ice composition, cosmic-ray ionization rate (1.3 × 10−17 s−1, 1 × 10−16 s−1, and 6 × 10−16 s−1), warm-up time (over 50, 200, and 1000 kyr), and initial (10, 15, and 25 K) and final temperatures (300 and 500 K). Results. Varying the initial ice compositions within the observed and expected ranges does not noticeably affect the modeled abundances indicating that the chemical make-up of hot cores is determined in the warm-up stage. Complex cyanides vinyl and ethyl cyanide (CH2CHCN and C2H5CN, respectively) cannot be produced in abundances (vs. H2) greater than 5 ×10−10 for CH2CHCN and 2 ×10−10 for C2H5CN with a fast warm-up time (52 kyr), while the lower limit for the observed abundance of C2H5CN toward source B3 is 3.4 ×10−10. Complex cyanide abundances are reduced at higher initial temperatures and increased at higher cosmic-ray ionization rates. Reaction-diffusion competition is necessary to reproduce observed abundances of oxygen-bearing species in our model. Conclusions. Within the context of this model, reproducing the observed abundances toward G35.20−0.74 Core B3 requires a fast warm-up at a high cosmic-ray ionization rate (~1 × 10−16 s−1) at a high gas density (>109 cm−3). The abundances observed at the other positions in G35.20-0.74N also require a fast warm-up but allow lower gas densities (~108 cm−3) and cosmic-ray ionization rates (~1 × 10−17 s−1). In general, we find that the abundance of ethyl cyanide in particular is maximized in models with a low initial temperature, a high cosmic-ray ionization rate, a long warm-up time (>200 kyr), and a lower gas density (tested down to 107 cm−3). G35.20−0.74 source B3 only needs to be ~2000 years older than B1/B2 for the observed chemical difference to be present, which maintains the possibility that G35.20−0.74 B contains a Keplerian disk.

Sign in / Sign up

Export Citation Format

Share Document