scholarly journals Kinetic Study of the Reaction of Rh(a4F9/2) with N2O, O2 and NO

1998 ◽  
Vol 17 (4) ◽  
pp. 219-237 ◽  
Author(s):  
Mark L. Campbell
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Rate Constants ◽  
Room Temperature ◽  
Reaction Rate ◽  
Removal Rate ◽  
Reaction Rates ◽  
Bimolecular Reaction ◽  
Temperature Rate

The gas phase reactivity of Rh(a4F9/2) with N2O, O2 and NO is reported. Removal rate constants for the excited states of rhodium below 13,000cm-1 are also reported. The reaction rate of Rh(a4F9/2) with N2O is relatively temperature insensitive. The rate constants for the bimolecular reaction are described in Arrhenius form by (1.3±0.3)×10−12exp⁡(−1.3±0.8KJ/mol/RT)cm3s−1 The reaction rates of the a4F9/2 state with O2 and NO are pressure dependent. For O2, the limiting low-pressure thirdorder, K0, and limiting high-pressure second-order, K∞, room temperature rate constants in argon buffer are (6.6±0.6)×10−30cm6s−1 and (2.1±0.2)×10−11cm3s−1, respectively. For NO, K2 and K∞ are (1.3±0.2×10−30cm6s−1) and (2.1±0.4)×10−11cm3s−1, respectively. The removal rates of the excited states are faster than the ground state by a factor of 2 or more.

scholarly journals Reaction rate of p14N →15Oγ capture to all bound states in potential cluster model

2020 ◽  
Vol 29 (01) ◽  
pp. 1930007 ◽  
Author(s):  
Sergey Dubovichenko ◽  
Nataliya Burkova ◽  
Albert Dzhazairov-Kakhramanov ◽  
Bekmurza Beysenov
Keyword(s):  
Excited States ◽  
Ground State ◽  
Cluster Model ◽  
Bound States ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Potential Cluster Model ◽  
Excitation Energies ◽  
Proton Capture ◽  
Calculation Results

Review of calculation results for astrophysical [Formula: see text]-factor of the [Formula: see text]N[Formula: see text]O capture reaction in the [Formula: see text]N channel of [Formula: see text]O was presented. It was carried out in the frame of the modified potential cluster model (MPCM) taking into account resonances in the [Formula: see text]O spectrum up to 3.2[Formula: see text]MeV at energy of incident protons varying of 30[Formula: see text]keV to 5[Formula: see text]MeV. It is possible to describe experimental data for the astrophysical [Formula: see text]-factors of the radiative proton capture on [Formula: see text]N to five excited states of [Formula: see text]O at excitation energies of 5.18[Formula: see text]MeV to 6.86[Formula: see text]MeV, only under assumption, that all five resonances are [Formula: see text] scattering waves. Quality new physical interpretation of the capture mechanism is discussed in this channel to the ground state of [Formula: see text]O. We assumed that the ground state of [Formula: see text]O is determined by the [Formula: see text]N[Formula: see text] channel with excited [Formula: see text]N[Formula: see text] cluster, which immediately allowed us to correctly describe order of values of the experimental [Formula: see text]-factor for capture to this state. Taking into account these results, the total [Formula: see text]-factor of the proton capture on [Formula: see text]N and the reaction rates to the ground and five excited states of [Formula: see text]O were determined at temperatures of 0.01[Formula: see text][Formula: see text] to 10[Formula: see text][Formula: see text]. The parametrization of the total reaction rate with a simple form is performed, which allows as to obtain [Formula: see text] equal to 0.06 with 5% errors of the calculated rate.

Atmospheric chemistry of iodine anions: elementary reactions of I−, IO−, and IO2− with ozone studied in the gas-phase at 300 K using an ion trap

2018 ◽  
Vol 20 (45) ◽  
pp. 28606-28615 ◽  
Author(s):  
Ricky Teiwes ◽  
Jonas Elm ◽  
Karsten Handrup ◽  
Ellen P. Jensen ◽  
Merete Bilde ◽  
...  
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Rate Constants ◽  
Room Temperature ◽  
Reaction Rate ◽  
Ion Trap ◽  
Elementary Reactions ◽  
Reaction Rate Constants ◽  
Ion Molecule Reactions

Using a radio-frequency ion trap to study ion–molecule reactions under isolated conditions, we report a direct experimental determination of reaction rate constants for the sequential oxidation of iodine anions by ozone at room temperature (300 K).

An experimental study of the reactivity of the hydroxide anion in the gas phase at room temperature, and its perturbation by hydration

1981 ◽  
Vol 59 (11) ◽  
pp. 1615-1621 ◽  
Author(s):  
Scott D. Tanner ◽  
Gervase I. Mackay ◽  
Diethard K. Bohme
Keyword(s):  
Experimental Study ◽  
Proton Transfer ◽  
Gas Phase ◽  
Rate Constants ◽  
Room Temperature ◽  
Gas Phase Reactions ◽  
Flowing Afterglow ◽  
Hydroxide Anion

Flowing afterglow measurements are reported which provide rate constants and product identifications at 298 ± 2 K for the gas-phase reactions of OH− with CH3OH, C2H5OH, CH3OCH3, CH2O, CH3CHO, CH3COCH3, CH2CO, HCOOH, HCOOCH3, CH2=C=CH2, CH3—C≡CH, and C6H5CH3. The main channels observed were proton transfer and solvation of the OH−. Hydration with one molecule of H2O was observed either to reduce the rate slightly and lead to products which are the hydrated analogues of the "nude" reaction, or to stop the reaction completely, k ≤ 10−12 cm3 molecule−1 s−1. The reaction of OH−•H2O with CH3—C≡CH showed an uncertain intermediate behaviour.

Excited-Atom Production by Electron Bombardment of Alkali-Halides

1986 ◽  
Vol 75 ◽  
Author(s):  
R. E. Walkup ◽  
Ph. Avouris ◽  
A. P. Ghosh
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Excited Atom ◽  
Alkali Halides ◽  
Electron Bombardment ◽  
Secondary Electrons ◽  
Excited Atoms ◽  
Positive Ions ◽  
Electronically Excited

AbstractWe present experimental results which suggest a new mechanism for the production of excited atoms and ions by electron bombardment of alkali-halides. Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the dependence of yield on incident electron current support a model in which excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. Similarly, gas-phase ionization of ground-state neutrals by secondary electrons accounts for a substantial portion of the positive ions produced by electron bombardment of alkali-halides.

Primary kinetic isotope effect in the gas phase photochlorination of ethyl chloride-1-d1

1984 ◽  
Vol 62 (5) ◽  
pp. 899-906 ◽  
Author(s):  
Jan Niedzielski ◽  
T. Yano ◽  
E. Tschuikow-Roux
Keyword(s):  
Activation Energy ◽  
Gas Phase ◽  
Isotope Effect ◽  
Ground State ◽  
Rate Constants ◽  
Kinetic Isotope Effect ◽  
Kinetic Isotope ◽  
Primary Reference ◽  
Hydrogen Deuterium ◽  
Increasing Temperature

The abstraction of hydrogen/deuterium from CH3CHDCl by ground state chlorine atoms produced photolytically from Cl2 has been investigated at temperatures betwen 280 and 368 K. The relative rates for the internal competition[Formula: see text]are found to conform to an Arrhenius rate law:[Formula: see text]These data, taken together with the external competition results for the C2H5Cl/CH3CHDCl system, in conjunction with the competitive results using CH4 as a primary reference, have yielded the rate constants (cm3 s−1):[Formula: see text]The relatively weak primary kinetic isotope effect, kH/kD, decreases with increasing temperature from 1,855 at 280 K to 1.66 at 365 K. The results are compared with those obtained based on the BEBO method. While both the trend and the magnitude of the kinetic isotope effect are satisfactorily predicted, the activation energy is not.

scholarly journals Photochemistry of Thymine in Protic Polar Nanomeric Droplets Using Electrostatic Embeding TD-DFT/MM

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6021
Author(s):  
Miquel Huix-Rotllant
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Radiative Decay ◽  
Td Dft ◽  
Dna Photodamage ◽  
Solvent Molecules ◽  
Energy Surfaces ◽  
Electrostatic Embedding

Thymine photochemistry is important for understanding DNA photodamage. In the gas phase, thymine undergoes a fast non-radiative decay from S2 to S1. In the S1 state, it gets trapped for several picoseconds until returning to the ground-state S0. Here, we explore the electrostatic effects of nanomeric droplets of methanol and water on the excited states of thymine. For this purpose, we develop and implement an electrostatic embedding TD-DFT/MM method based on a QM/MM coupling defined through electrostatic potential fitting charges. We show that both in methanol and water, the mechanism is similar to the gas phase. The solvent molecules participate in defining the branching plane of S0/S1 intersection and have a negligible effect on the S1/S2 intersection. Despite the wrong topology of the ground/excited state intersections, electrostatic embedding TD-DFT/MM allows for a fast exploration of the potential energy surfaces and a qualitative picture of the photophysics of thymine in solvent droplets.

Visible Luminescence of Eu3+ Ions in Lithium Barium Borate Glass

2016 ◽  
Vol 702 ◽  
pp. 66-70
Author(s):  
Keerati Kirdsiri ◽  
Benchaphorn Damdee ◽  
Jakrapong Kaewkhao
Keyword(s):  
Excited States ◽  
Ground State ◽  
Room Temperature ◽  
State Level ◽  
Barium Borate ◽  
Absorption Bands ◽  
Visible Luminescence ◽  
Barium Borate Glass ◽  
Quench Method ◽  
Ground State Level

Europium doped lithium barium borate glasses were fabricated by conventional melt-quench method and were analyzed their physical, optical and luminescence properties through absorption, excitation, emission and decay analysis at room temperature. The experimental data revealed that the five discrete absorption bands peaking at 393, 464, 532, 2032 and 2212 nm due to the transitions from 7F0 ground state level to various excited states of Eu3+ ions. The luminescence of Eu3+ in visible bands were observed under 394 nm pumping.

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