O2(b1Î£g+) Quenching by O2, CO2, H2O, and N2 at Temperatures of

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O(b# ) Quenching by O, CO, HO, and N at Temperatures of 300-800 K Marsel Vakifovich Zagidullin, Nikolay Anatol'evich Khvatov, Iakov A Medvedkov, Georgy I Tolstov, Alexander Moiseevich Mebel, Michael Charles Heaven, and Valeriy N Azyazov J. Phys. Chem. A, Just Accepted Manuscript • DOI: 10.1021/acs.jpca.7b07885 • Publication Date (Web): 11 Sep 2017 Downloaded from http://pubs.acs.org on September 16, 2017

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The Journal of Physical Chemistry

O2(b1 ) Quenching by O2, CO2, H2O, and N2 at Temperatures of 300-800 K M.V. Zagidullin1,2, N.A. Khvatov1,2, I.A. Medvedkov1, G.I. Tolstov1, A.M. Mebel1,3,*, M.C. Heaven1,4, and V.N. Azyazov1,2,† 1

Samara National Research University, Samara 443086, Russia 2

3

Lebedev Physical Institute, Samara 443011, Russia

Florida International University, Miami, Florida 33199, USA 4

Emory University, Atlanta, Georgia 30322, USA

Abstract Rate constants for the removal of O2 b1Σ by collisions with O2, N2, CO2 and H2O have been determined over the temperature range from 297 to 800 K. O2(b1Σ ) was excited by pulses from a tunable dye laser, and the deactivation kinetics were followed by observing the temporal behavior of the b1Σ - X3Σ fluorescence. The removal rate constants for CO2, N2 and H2O were not strongly dependent on temperature, and could be represented by the expressions kCO2=(1.18±0.05)×10-17×T1.5×exp

;

595 ± 25

kH2O=(1.27±0.08)×10-16×T1.5×exp

T

kN2=(8±0.3)×10-20×T1.5×exp

503 ± 21 T

,

and

cm3 molecule-1 s-1. Rate constants for O2(b1Σ+)

675 ± 27 T

removal by O2(X), being orders of magnitude lower, demonstrated a sharp increase with temperature, represented by the fitted expression kO2=(7.4±0.8)×10-17×T0.5×exp

cm3

-1104.7 ± 53.3 T

molecule-1 s-1. All of the rate constants measured at room temperature were found to be in good agreement with previously reported values.

* †

A corresponding author. E-mail: [email protected] A corresponding author. E-mail: [email protected] 1 ACS Paragon Plus Environment


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1. Introduction Oxygen in the electronically excited state b1Σ is involved in various chemical, radiative and energy-exchange processes in the atmosphere1, oxygen-containing gas discharges2, combustion3, and the active medium of an oxygen-iodine laser (OIL)4. Reactions with O2(b1Σ ) can produce chemically active atmospheric species such as odd-hydrogen (HOx) or odd-nitrogen (NOx) intermediates5,6. Airglow emission from the O2 b1Σ - X3Σ transition (762 nm) contributes significantly to the radiation budget of the atmosphere1. This emission is used to derive atmospheric ozone densities7. O2(b1Σ ) is also formed in the atmospheres of terrestrial planets as a result of secondary reactions initiated by UV photolysis of oxygen-containing species8, 9. The contribution of O2(b1Σ ) to I2 dissociation in the active medium of an oxygen-iodine laser has been the subject of several previous investigations. Initially, it was proposed that energy transfer from O2(b1Σ ) was the dominant dissociation mechanism10 in the chemically driven laser, but subsequent studies showed that this process was a minor channel that only contributes to the initiation of the dissociation process11,12. O2(b1Σ ) molecules in electric discharge driven OIL are formed primarily by direct electron impact and the quenching of O(1D) by O213. In this system O2(b1Σ ) is involved in the I2 dissociation process14, but the reactions of other discharge products dominate. Ignition and combustion enhancements in various mixtures by means of plasma15 or laser3 excitation of singlet states of oxygen (a1∆g, b1Σ ) have been considered. Excitation of the O2(b1Σ ) state by laser radiation with wavelength λ = 762 nm has strong effects on the initiation of detonation in the supersonic flow of a H2/O2 mixture16. Measurements of the rate constants of elementary processes involving O2(b1Σ ) molecules were undertaken by many investigators. For room temperature conditions, the rate constants for quenching of O2(b1Σ ) were measured repeatedly, for example, by water vapor6, 1719

carbon dioxide6, 17, 19-23, nitrogen6, 19, 20, 22 and oxygen18, 24-26. The gas temperature in many oxygen-containing mixtures can be much higher than

ambient when reactions are in progress, which makes it important to study the kinetics of the formation and deactivation of O2(b1Σ ) molecules at elevated temperatures. There is very little published data concerning the deactivation kinetics of O2(b1Σ ) at temperatures above 350 K. Deactivation by individual atmospheric molecules (O2, N2, CO2) at temperature within the 6001800 K range was investigated only in27,28, where shock tube compression of the products of an oxygen low-temperature plasma was used to obtain high gas temperatures.

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In the present work, time-resolved emission from the O2 b1Σ , v = 0 - X3Σ , v = 0 transition has been used to determine the rate constants of deactivation of O2(b1Σ , v = 0) over the temperature range from 297 to 800 K.

2. Experiment The apparatus for recording time-resolved emission from oxygen O2(b1Σ ) is shown in Fig. 1. A gas mixture containing oxygen flows through the fluorescence cell (FC), which consists of a cylindrical quartz tube 40 cm long, with an internal diameter of 15 mm. The outer wall of the tube was covered with a single layer of thin copper foil, and then with two layers of fiberglass to prevent the contact of copper with the electrical heater. A nichrome tape was coiled over the fiberglass layer, through which an electric current was passed. The ends of the FС were sealed by quartz windows, mounted at an angle to avoid problems from back reflections. Gases of UHP quality, oxygen (Linde, 99.999%), carbon dioxide (Linde, 99.999%), and nitrogen (Linde, 99.999%), were used in the experiments. Residual water vapor in the cylinder (≤0.001%) introduced a significant complication in measurements of the O2(b1Σ ) relaxation rate for some inefficient quenching species like Ar, He, and O2. In this case, the gas flow before entering the FC was passed through a water vapor trap (WVT). This consisted of a coil of copper tubing (5.5 mm internal diameter, 2m long), immersed in an ethanol slush bath at the temperature of approximately -100°С. Gas flow rates were controlled by flowmeters (Bronkhorst, Mass-View MV-302) and needle valves. The FC was evacuated by a Scroll pump (Edwards), and the pumping rate was adjusted using a ball valve. The total gas flow through the FC did not exceed 3 L/min (here and in the following text, the volumetric flow rate of gas is given for standard conditions). The gas pressure in the FC was measured using a METRAN 150-TA sensor and was varied over the range of 0.5 to 1.5 atm. The laser pulse energy was measured using an OPHIR-PE50BFV2 power meter. O2(b1Σ ) was populated directly using pulsed laser excitation of the b1Σ ,v=1←X3Σ , v=0 band near 690 nm. Laser radiation was provided by a tunable dye laser (Sirah Precision Scan, PSCAN-D-18-EG) pumped by the second harmonic (532 nm) of a Nd:YAG laser (QuantaRay, PR0-290-10E). The dye laser beam (pulse energy 0.15 J, beam diameter 6 mm, pulse duration 10 ns, repetition rate 10 Hz, spectral emission width 0.03 nm) was directed along the central axis of the FC. In excess O2(X), the vibrationally excited O2(b1Σ ,v=1) was rapidly transferred to O2(b1Σ ,v=0) by efficient E-E and V-V energy-exchange processes29. A rectangular window, 2 cm long and 1 cm high, was located at the center of the FC. This aperture 3 ACS Paragon Plus Environment


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was free of insulating materials and nichrome tape. Oxygen b1Σ ,v=0→X3Σ ,v=0 emission was observed through this window, along an axis that was perpendicular to the dye laser beam. The light was collected by a 5 cm focal length lens, and focused on the entrance slit of a monochromator (MDR-206). This was used as a band-pass filter, transmitting wavelengths in the 762±8 nm range. Additional long-pass filters were used to suppress the scattered radiation at 690 nm. Time-resolved LIF signals were recorded using a photomultiplier (Hamamatsu R636-10). A digital oscilloscope (LeCroy Wavesurfer-3054R) was used to signal average 200 waveforms for each measurement. The gas temperature in the LIF region was measured by a thermocouple.

3. Results It was observed that the temperature of the gas mixture in the LIF observation region, directly opposite the center of the fluorescence observation window, was somewhat lower than the upstream or downstream temperatures. For example, at a nominal temperature of 800 K, the temperature near the center of the window was 20 K lower than at the edges. At lower temperatures, the difference was smaller. The temperature gradient was present because the window was heated only by transfer of heat through the wall of the quartz tube. Thus, the temperature and number density distributions in the observation zone slightly varied. The pressure throughout the FC was assumed to be constant. Temperature variations were taken into account in estimating the measurement errors. Typical

temporal

profiles

of

the

emission

intensity

for

the

transition

O2

b1Σ ,v=0→X3Σ ,v=0 at the oxygen partial pressure PO2 = 750 Torr and the CO2 number density NCO2 = 1.8×1016 cm-3 at gas temperatures T = 297 and 800 K are exhibited on Fig. 2. With increasing temperature, the amplitude of the LIF signal decreased due to the drop in the oxygen number density, a decrease in the absorption cross section from line broadening, and a decrease in the relative population of the specific rotational level. The loss of signal was accompanied by an increase in the noise resulting from thermal emission from the FC walls. As a consequence, the signal-to-noise ratio became unworkable at temperatures above 800 K. The intensity of the sharp spike at zero time in this trace was the same with the dye laser tuned on- and off-resonance indicating that the spike was caused by scattered light from the laser pulse. The time-resolved LIF signals (I) at time t>0 exhibited single exponential decay characteristics of the form I(t)=I(0)exp(-Kt). In a two-component mixture of oxygen (of number density nO2) and an admixed gas M (number density nM), the rate K depends linearly on their concentrations such that K=kO2nO2+kMnM. Application of the ideal gas approximation yields the expression 4 ACS Paragon Plus Environment

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G GO2

=kO2 +

GM k . GO2 M

(1)

where P is the total pressure in the FC, R is the gas constant, GM, and GO2 are the molar gas flow rates. kO2 and kM are the rate constants of the following processes: O2(b1Σ ) + O2 → 2O2

(2)

O2(b1Σ ) + M→ O2 + M.

(3)

For each fixed temperature the dependence (1) was determined and the rate constant kM was extracted using a linear Stern-Volmer analysis. For the experiments described in the following sections, the oxygen flow rate was fixed at 700 cm3/min. No additional steps were taken to reduce the background level of H2O in the O2 stream, except for the measurements of deactivation by O2(X) (see below).

CO2 Carbon dioxide was added to the oxygen flow to investigate the ratio range GCO2/GO2 = 0 to 0.007. As an example, Fig. 3 shows two plots of Eq. (1) at 297 K and 800 K. Linear regression fit of data at 297 K gave kCO2 = (4.61 ± 0.13)×10-13 cm3/s, which is close to previously reported values, as can be seen from Table 1. The rate constant kCO2 was measured over the temperature range from 297 to 800 K, and the results are shown in Fig. 4. Up to 600 K the rate constant did not show a significant dependence on temperature. This was in accordance with previous results.6,22 However, between 600 and 800 K the rate constant increased slightly with temperature. Linear fit of data for 800 K presented in Fig. 3 (upper line) gave a value of the rate constant 5.8×10-13 cm3/s. The expression kCO2=(1.18±0.05)×10-17×T1.5×exp

was

595 ± 25 T

determined by non-linear least squares fitting to the data.

N2 Deactivation by N2 was examined for gas flow ratios in the range of GN2/GO2 = 0 to 2.5. Linear fitting to the room temperature decay rate data gave kN2 = (2.2 ± 0.2)×10-15 cm3/s, which is close to the literature values presented in Table 1. As can be seen from Fig. 5 up to a temperature of 500 K, the change in the value of kN2 with temperature was not noticeable. In the range from 500 to 800 K the rate constant increased with the temperature, reaching a value of 3.4×10-15 cm3/s at 800 K. The temperature dependence was adequately represented by the expression kN2=(8±0.3)×10-20×T1.5×exp

503 ± 21 T

.

H 2O 5 ACS Paragon Plus Environment


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To entrain H2O in the gas flow, a small portion of oxygen with a flow rate G1O2 was bubbled through an in-line tank that was immersed water-ice bath held at 0°C. Flow ratios in the range G1O2 /GO2 = 0 to 0.08 were used to vary the partial pressure of H2O. The dependence of the value of K the can be represented in the form:

where =

G GO2

=kO2 +

GW k , GO2 H2O

(4)

is the molar flow rate of water through the FC, PW and PB are partial

pressure of water vapor and the total pressure above the water surface in the tank. It was assumed that complete saturation of the oxygen flow with water vapor was achieved, yielding a partial pressure of 4.58 Torr at T = 0°C. Analysis of data for gas temperature T = 297 K gave kH2O = 6.12×10-12 cm3/s, which is close to the literature values shown in Table 1. Values of kH2O at other temperatures are shown in Fig. 6. Here it can be seen that as the temperature increases, the quenching rate constant kH2O decreases, reaching a minimum of 5×10-12 cm3/s at 500K, and then acquires a positive slope. The weak temperature dependence of kH2O in this range is in accordance with previous measurements6. At a temperature of about 800K, kH2O reaches a value of 7.3×10-12 cm3/s. Fitting to the data presented in Fig. 5 (solid curve) defined the expression kH2O=(1.27±0.08)×10-16×T1.5×exp

.

675 ± 27 T

O2 Quenching of O2(b1Σ ) by O2(X) is known to be a very slow process. As a consequence, measurements of the rate constant can be seriously compromised by the presence of trace impurities. Our initial attempt to measure the rate constant was based on the expectation that a plot of K verses nO2 would exhibit a slope of kO2. However, room temperature measurements, performed without further purification of the O2, yielded rate constants that were 2 – 3 times greater than the literature values. We attributed this discrepancy to the presence of water vapor contamination in the oxygen cylinder. This was particularly problematic for the O2 quenching measurements, as the rate constant for quenching by H2O is larger by a factor of 105. To reduce the H2O content, the oxygen flow was passed through a water vapor trap held at -100°C. At the outlet of the trap, it was assumed that the water vapor concentration would be independent of the oxygen flow rate and close to the saturated concentration (3×1011 cm-3). The data could then be analyzed using Eq. (4) with nH2O held constant. The deactivation rate can then be expressed as

= + , where nO2 = P/RT is the oxygen concentration in the FС and K0=kH2OnH2O is the quenching rate by residual water. Fig. 7 shows the dependence of K on the oxygen concentration at room temperature. Linear fitting gives kO2 = (3.67 ± 0.06)×10-17 cm3/s and K0 = 53 ± 17 s-1. The kO2 value was in good agreement with the results of references 25 and 26. 6 ACS Paragon Plus Environment

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Assuming that the value of K0 is due only to deactivation with water, we obtain an estimate of its concentration in the FC of K0/kH2O ≈ 8×1012 сm-3. This is much higher than the saturated vapor pressure at -100°C, and probably results from H2O desorbing from the gas delivery lines and the inner walls of the FC. The dependence of the rate constant kO2 on temperature was found to be much stronger than for the molecules N2, CO2 and H2O. Therefore, Fig. 8 presents the temperature dependence of kO2 on a logarithmic scale as a function of 1/T. The dependence of kO2 on temperature can be fitted analytically as kO2 = (7.4±0.8)×10-17T0.5×exp

cm3/s. Borrell et al.28 have also

-1104.7 ± 53.3 T

observed a strong dependence of kO2 on temperature in the range of 300−1850 K. Only two measured points at 300 K and 600 K from their temperature interval belong to the 300−800 K range considered here. The value of kO2 = 1.7×10-16 cm3/s for T = 300 K reported in reference 28 is about four times higher than the other literature values shown in Table 1. An increase in temperature from 300 to 600 K results in a growth of kO2 by factors of 8.2 (Borrell et all.28) and 7.6 (this work). Taking into account the strong dependence of kO2 on temperature, this subtle difference can be explained by possible error in determining the temperature in the shock wave.

4. Discussion Two theoretical approaches have been used in the literature to explain the mechanism and to justify the values of rate constants for quenching O2(b1Σ ) with various collisional counterparts. One is a semiempirical approach based on semiclassical Rosen–Zener approximation30 within which the quenching process is assumed to occur, for example, when the energies of electronic and vibrational states of the O2(b1Σ , v ) + M(v2) pair closely match those of the O2(a1∆, v ) + M(v4) pair. When the electronic state of the collisional partner molecule M does not change, the transition mechanism is described to proceed by the electronic-vibrational (E-V) energy transfer, and when the electronic state of M changes, the transition proceeds by the electronic-electronic (E-E) energy transfer. Kirillov31,32 has successfully evaluated rate constants for the removal of O2(b1Σ , v = 0 − 15) and O2(a1∆, v = 0 − 20) in collisions with ground electronic state O2, N2, and CO molecules in various vibrational states employing a Rosen–Zener analytical expression. Although the rate coefficients computed by Kirillov are close to the available experimental values, this formalism relies upon the use of empirical parameters and does not provide much information on the underlying nonadiabatic mechanisms of the quenching process. More intimately, the mechanism can be understood via ab initio calculations of the excited and ground state potential energy surfaces of the O2/M molecular dimer, and the spinorbit coupling or nonadiabatic coupling matrix elements between these surfaces. These results 7 ACS Paragon Plus Environment


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are then used in quantum dynamics calculations on the coupled surfaces. Such calculations are sophisticated and very time-consuming, but would in principle reveal where the crossings between different electronic surfaces (conical intersections) occur and allow for evaluation of the probabilities for the dimer molecular system to funnel through the conical intersections, resulting in quenching of the higher electronic state. Liu and Morokuma33 were first to report detailed high-level

ab

initio

potential

energy

surfaces

for

the

O2(b1Σ , a ∆, & Σ)

+

O2(b1Σ , a ∆, & Σ) dimer. They used the calculated surfaces and in particular, S2/T7 and S1/T7 seams of crossing to describe the mechanism of the O2(a ∆) + O2(a ∆ ) → O2(b1Σ ) + O2(X3Σ ) pooling reaction. Liu and Morokuma found a 0.45 eV barrier on the seam of crossing of the b+X and a+a manifolds relative to the a+a asymptote and estimated the rate constant for the pooling reaction based on the Landau-Zener formalism. Later, Lu et al.34 performed fivedimensional nonadiabatic quantum dynamics studies on the S2 and T7 surfaces for the O2 dimer in coplanar configurations, which involved spin-orbit coupling between them. These calculations allowed the authors to calculate the spin-orbit induced transition probability as a function of collision energy and to evaluate the rate constant for the pooling transition. Dayou et al.35 studied the effect of nonadiabatic couplings on the collisional removal of O2(b1Σ ) by O2(X3Σ ) using two-dimensional adiabatic and quasidiabatic potential energy surfaces for the excited dimer states and the respective nonadiabatic couplings. Then, they performed quantum dynamics calculations for the removal of the first ten vibrational states of O2(b1Σ ), which showed a dominance of the E-V relaxation mechanism over the vibration-translation energy transfer. The reduced-dimensionality model used in this work was able to provide only a qualitative consistence with the experimental observations. However, the authors noticed that a proper description of the appropriate crossing seam may be sufficient to portray the nonadiabatic dynamics. It is likely that the energies and structures of the conical intersections between the electronic states involved in the quenching process hold the keys to understanding the quenching rate constants and their temperature dependence. For instance, if the dimer system funnels through a conical intersection which lies lower in energy than the O2(b1Σ ) + M asymptote, one could expect that the quenching process would be relatively fast and the rate constant would exhibit no (or a slightly negative) temperature dependence, which turns into a slightly positive temperature dependence at higher temperatures. This kind of behavior, seen here for kCO2 and kH2O is typical for barrierless chemical reactions occurring without activation energy. Alternatively, if the intersection has its energy above the asymptote of the initial O2(b1Σ ) + M state, the quenching rate constant is expected to be low and to exhibit well-defined positive 8 ACS Paragon Plus Environment

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temperature dependence. Since the quenching process is nonadiabatic, the rate constants are also affected by the behavior of spin-orbit coupling (if a singlet-triplet intersection is involved) or nonadiabatic coupling (if quenching involves two states of the same multiplicity). The experimental results observed here for O2(b1Σ )/O2(X3Σ ) are consistent with a process requiring activation energy. Indeed, the calculations by Liu and Morokuma have shown that conical intersections between the T6 and T5 states involved in the O2(b1Σ ) + O2(X3Σ ) → O2(a ∆ ) + O2(X3Σ ) quenching reaction exist for rectangular (D2h) and trans (C2h) geometries of the dimer and reside significantly higher in energy than the separated O2(b1Σ ) + O2(X3Σ ) reactants.

5. Conclusion In summary, we report the first measurements of the temperature dependence of rate constants for removal of O2(b1Σ , v = 0) in collisions with M = CO2, N2, H2O and O2 for the temperature range 297−800 K. Our results for the rate constants at room temperature are in good agreement with previous studies. The temperature dependences of kM were found to be modest for M = CO2, N2, H2O. In contrast, kO2 exhibits a strong temperature dependence, which must be taken into account in kinetic models of plasma combustion phenomena. These results are now available for modeling of terrestrial and planetary atmospheres, oxygen plasmas and combustion processes.

Acknowledgments This work was supported by the Ministry of Education and Science of the Russian Federation under the Grant No. 14.Y26.31.0020 to Samara University.



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References 1. Slanger, T. G.; Copeland, R. A. Energetic Oxygen in the Upper Atmosphere and the Laboratory. Chem. Rev. 2003, 103, 4731-4766. 2. Braginsky, O. V.; Kovalev, A. S.; Lopaev, D. V.; Mankelevich, Yu. A.; Proshina, O. V.; Rakhimova, T. V.; Rakhimov, A. T.; Vasilieva, A. N. Discharge Singlet Oxygen Generator for Oxygen-Iodine Laser: I. Experiments with RF Discharges at 13.56 and 81 MHz. J. Phys. D: Appl. Phys. 2006, 39, 5183–5190. 3. Starik, A. M.; Kuleshov, P. S.; Titova, N. S. Comprehensive Analysis of Combustion Initiation in Methane-Air Mixture by Resonance Laser Radiation. J. Phys. D: Appl. Phys. 2009, 42, 175503-175521. 4. Perram, G. P.; Approximate Analytic Solution for the Dissociation of Molecular Iodine in the Presence of Singlet Oxygen. Int. J. Chem. Kinet. 1995, 27, 817-828. 5. Dunlea, E. J.; Talukdar, R. K.; Ravishankara, A. R. Kinetics and Products of the Reaction O2(b1Σ ) with N2O. Z. Phys. Chem. 2010, 224, 989-1007. 6. Dunlea, E. J.; Talukdar, R. K.; Ravishankara, A. R. Kinetic studies of Reactions of O2(b1Σ ) with Several Atmospheric Molecules. J. Phys. Chem. A 2005, 109, 3912-3920. 7. Mlynczak, M. G.; Morgan, F.; Yee, J.-H.; Espy, P.; Murtagh, D.; Marshall, B.; Schmidlin, F. Simultaneous measurements of the O2(1∆) and O2(1Σ) Airglows and Ozone in the Daytime Mesosphere. Geophys. Res. Lett. 2001, 28, 999-1002. 8. Krasnopolsky, V. A. Excitation of the Oxygen Nightglow on the Terrestrial Planets. Planet. Space Sci. 2011, 59, 754-766. 9. Migliorini, A.; Piccioni, G.; Capaccioni, F.; Filacchione, G.; Tosi, F.; Gérard, J. C. Comparative Analysis of Airglow Emissions in Terrestrial Planets, Observed with VIRTIS-M Instruments on Board Rosetta and Venus Express. Icarus. 2013, 226, 1115-1127. 10. Arnold, S. J.; Finlayson, N.; Ogryzlo, E. A. Some Novel Energy-Pooling Processes Involving O2(1∆g). J. Chem. Phys. 1966, 44, 2529−2530. 11. Azyazov, V. N.; Heaven, M. C.; Role of O2(b) and I2(A′,A) in Chemical Oxygen-Iodine Laser Dissociation Process. AIAA Journal. 2006, 44, 1593-1600. 12. Zagidullin, M. V.; Khvatov, N. A.; Malyshev, M. S.; Svistun, M. I. Dissociation of Molecular Iodine in a Flow Tube in the Presence of O2(1Σ) Molecules. J. Phys. Chem. A. 2012, 116, 10050-10053. 13. Kovalev, A. S.; Lopaev, D. V.; Mankelevich, Y. A.; Popov, N. A.; Rakhimova, T. V.; Poroykov, A. Y.; Carroll, D. L. Kinetics of O2(b1Σ ) in Oxygen RF Discharges. J. Phys. D: Appl. Phys. 2005, 38, 2360. 10 ACS Paragon Plus Environment

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14. Palla, A. D.; Carroll, D. L.; Verdeyen, J. T.; Solomon, W. C. Mixing Effects in Postdischarge Modeling of Electric Discharge Oxygen-Iodine Laser Experiments. J. Appl. Phys. 2006, 100, 023117. 15. Starik, A. M.; Loukhovitski, B. I.; Sharipov, A. S.; Titova, N. S. Physics and Chemistry of the Influence of Excited Molecules on Combustion Enhancement. Phil. Trans. R. Soc. A. 2015, 373, 20140341. 16. Starik, A. M.; Titova, N. S. Kinetics of Detonation Initiation in the Supersonic Flow of the H2 + O2(air) Mixture in O2 Molecule Excitation by Resonance Laser Radiation. Kinet. Catal. 2003, 44, 28-39. 17. Aviles, R. G.; Muller, D. F.; Houston, P.L. Quenching of Laser-Excited O2(b1Σ ) by CO2, H2O, and I2. Appl. Phys. Lett. 1980, 37, 358-360. 18. Thomas, R. G.; Thrush, B. A. Quenching of O2(b1Σ ) by Ground State O2. J. Chem. Soc. Faraday Trans. 2. 1975, 71, 664-667. 19. Shi, J.; Barker, J. R. Kinetic Studies of the Deactivation of O2(b1Σ ) and O(1D). Int. J. Chem. Kinet. 1990, 22, 1283-1301. 20. Wildt, J.; Bednarek, G.; Fink, E. H.; Wayne R. P. Laser Excitation of O2(b1Σ , v= 0, 1, 2) – Rates and Channels of Energy Transfer and Quenching. Chem. Phys. 1988, 122, 463-470. 21. Muller, D. F.; Houston P. L. Direct Observation of Electronic-to-Vibrational Energy Transfer from O2(1Σ) to CO2(v3). J. Phys. Chem. 1981, 85, 3563-3565. 22. Choo, K. Y.; Leu, M. T. Rate Constants for the Quenching of Metastable O2(b1Σ ) Molecules. Int. J. Chem. Kinet. 1985, 17, 1159-1167. 23. Azyazov, V. N.; Mikheyev, P. A.; Postell, D.; Heaven, M. C. О2(a1∆) Quenching in the O/O2/O3 System. Chem. Phys. Lett. 2009, 482, 56–61. 24. Lawton, S. A.; Novick, S. E.; Broida, H. P.; Phelps, A. V. Quenching of Optically Pumped O2(b1Σ ) by Ground State O2 Molecules. J. Chem. Phys. 1977, 66, 1381-1382. 25. Kebabian, P. L.; Freedman, A. Rare Gas Quenching of Metastable O2(b1Σ ) at 295K. J. Phys. Chem. A 1997, 101, 7765-7767. 26. Knickelbein, M. B.; Marsh, K. L.; Ulrich, O. E.; Busch, G. E. Energy Transfer Kinetics of Singlet Molecular Oxygen: The Deactivation Channel for O2(b1Σ ). J. Chem. Phys. 1987, 87, 2392-2393. 27. Borrell, P. M.; Borrell, P.; Richards, D. S.; Quinney, D. The Quenching of O2(b1Σ ) at High Temperatures. J. Chem. SOC., Faraday Trans. 2. 1987, 83, 2045-2052.



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28. Borrell, P. M.; Borrell P.; Grant, K.R.; Pedley, M. D. Rate Constants for the Energy-Pooling and Quenching Reactions of Singlet Molecular Oxygen at High Temperatures. J. Phys. Chem., 1982, 86, 700-703. 29. Kalogerakis, K. S.; Copeland, R. A.; Slanger, T. G. Collisional Removal of O2(b1Σ , v = 2, 3). J. Chem. Phys. 2002, 116, 4877-4885. 30. Rosen, N.; Zener, C. Double Stern-Gerlach Experiment and Related Collision Phenomena. Phys. Rev. 1932, 40, 502. 31. Kirillov, A. S. Calculation of Rate Coefficients for the Interaction of Singlet and Triplet Vibrationally Excited Oxygen. Quant. Electron. 2012, 42, 653. 32. Kirillov, A. S. The Calculations of Quenching Rate Coefficients of O2(b1Σ ) in Collisions with O2, N2, CO, CO2 Molecules. Chem. Phys. 2013, 410, 103-108. 33. Liu, J.; Morokuma, K. Ab Initio Potential-Energy Surfaces of O2(X3Σ , a1∆ , b1Σ ) + O2 (X3Σ , a1∆ , b1Σ ): Mechanism of Quenching of O2(a1∆ ). J. Chem. Phys. 2005, 123, 204319. 34. Lu, R. F.; Zhang, P. Y.; Chu, T. S.; Xie, T. X.; Han, K. L. Spin-Orbit Effect in the Energy Pooling Reaction O2(a1∆) + O2(a1∆) → O2(b1Σ) + O2(X3Σ). J. Chem. Phys. 2007, 126, 124304. 35. Dayou, F.; Hernández, M. I.; Campos-Martínez, J.; Hernández-Lamoneda, R. Nonadiabatic Couplings in the Collisional Removal of O2(b1Σ ) by O2. J. Chem. Phys. 2010, 132, 044313.


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Table 1. Overall Room Temperature Rate Constants for Deactivation of O2(b1Σ ). Quenching species CO2, 10-13 cm3/s

Rate constant 3.39 4.53 4.0 2.4 5.0 4.6 6.1 4.61

Ref. 6 17 19 20 21 22 23 This work

N2, 10-15 cm3/s

2.28 2.32 2.2 1.7 2.2

6 19 20 22 This work

H2O, 10-12 cm3/s

5.41 6.71 4.6 6.0 6.12

6 17 18 19 This work

O2, 10-17 cm3/s

4.6 3.8 4.25 5.6 3.67

18 24 25 26 This work



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Figure captions Figure 1. Schematic diagram of the temperature-controlled time-resolved oxygen fluorescence apparatus. Figure 2. Temporal profiles of the O2(b1Σg+)/CO2 mixture recorded for PO2 = 750 Torr and NCO2 = 1.8×1016 cm-3 at gas temperatures T = 297 K (red curve) and T = 800 K (black curve). Figure 3. Rates of O2(b1Σ ) removal by CO2 for PO2 = 750 Torr at the temperatures of 297 K (•) and 800 K ( ). Solid lines show linear regression fits. Figure 4. Rate constant kCO2 as a function of temperature. Solid curve is the best fit of experimental data to kCO2 = (1.18 ± 0.05)×10-17×T1.5×exp

.

595 ± 25 T

Figure 5. Rate constant kN2 as a function of temperature. Figure 6. Rate constant kH2O as a function of temperature. Figure 7. The rate of O2(b1Σ ) removal by O2 at a temperature of 297K. Figure 8. Rate constant kO2 as a function of temperature.


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Figure 1



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Figure 2


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Figure 3



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Figure 4


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Figure 5



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Figure 6


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Figure 7



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Figure 8


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TOC graphic


O2(b1Î£g+) Quenching by O2, CO2, H2O, and N2 at Temperatures of

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