1
|
He F, Wei Y, Maffei S, Livermore PW, Davies CJ, Mound J, Xu K, Cai S, Zhu R. Equatorial auroral records reveal dynamics of the paleo-West Pacific geomagnetic anomaly. Proc Natl Acad Sci U S A 2021; 118:e2026080118. [PMID: 33972442 PMCID: PMC8157951 DOI: 10.1073/pnas.2026080118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Localized regions of low geomagnetic intensity such as the South Atlantic Anomaly allow energetic particles from the Van Allen radiation belt to precipitate into the atmosphere and have been linked to a signature in the form of red aurora-like airglow visible to the naked eye. Smoothed global geomagnetic models predict a low-intensity West Pacific Anomaly (WPA) during the sixteenth to nineteenth centuries characterized by a simple time dependence. Here, we link the WPA to an independent database of equatorial aurorae recorded in Seoul, South Korea. These records show a complex fluctuating behavior in auroral frequency, whose overall trend from 1500 to 1800 AD is consistent with the locally weak geomagnetic field of the WPA, with a minimum at 1650 AD. We propose that the fluctuations in auroral frequency are caused by corresponding and hitherto unknown fluctuations in the regional magnetic intensity with peaks at 1590 and 1720 AD, a time dependence that has been masked by the smoothing inherent in regularized global geomagnetic models. A physical core flow model demonstrates that such behavior requires localized time-dependent upwelling flows in the Earth's core, possibly driven by regional lower-mantle anomalies.
Collapse
Affiliation(s)
- Fei He
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yong Wei
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China;
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Stefano Maffei
- School of Earth and Environment, University of Leeds, LS2 9JT Leeds, United Kingdom;
| | - Philip W Livermore
- School of Earth and Environment, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Christopher J Davies
- School of Earth and Environment, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Jon Mound
- School of Earth and Environment, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Kaihua Xu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Shuhui Cai
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China
| | - Rixiang Zhu
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China
| |
Collapse
|
2
|
Chang Y, Li Q, An F, Luo Z, Zhao Y, Yu Y, He Z, Chen Z, Che L, Ding H, Zhang W, Wu G, Hu X, Xie D, Plane JMC, Feng W, Western CM, Ashfold MNR, Yuan K, Yang X. Water Photolysis and Its Contributions to the Hydroxyl Dayglow Emissions in the Atmospheres of Earth and Mars. J Phys Chem Lett 2020; 11:9086-9092. [PMID: 33047964 DOI: 10.1021/acs.jpclett.0c02803] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Airglow is a well-known phenomenon in the Earth's upper atmosphere, which arises from the emissions of energetic atoms and molecules. The Meinel band emission from high vibrationally excited OH(X) radicals is one of the more important contributors to the airglow from the mesosphere/lower thermosphere. The H + O3 reaction has long been regarded as the dominant source of these OH(X, high v) radicals. Here we demonstrate that vacuum ultraviolet (VUV) photolysis of water vapor at λ ∼ 112.8 nm represents another source of exceptionally highly vibrationally excited OH(X) radicals, with a nascent vibrational state population distribution that maximizes at v = 9 and extends to at least the v = 15 level. Atmospheric chemistry modeling indicates that OH(X, high v) radicals from H2O photolysis might be detectable in the OH Meinel band dayglow in the upper atmosphere of Earth and should dominate the corresponding emission from the Martian atmosphere. VUV photolysis of H2O also produces electronically excited OH(A) radicals, and simultaneous detection of emissions from OH(X, high v) and OH(A) is shown to offer a route to identifying high-oxygen exoplanetary atmospheres.
Collapse
Affiliation(s)
- Yao Chang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Qinming Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Feng An
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210023, China
| | - Zijie Luo
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- School of Science, Dalian Maritime University, 1 Linghai Road, Dalian, Liaoning 116026, P. R. China
| | - Yarui Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- School of Physics, Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, Dalian University of Technology, Dalian 116024, China
| | - Yong Yu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zhigang He
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zhichao Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Li Che
- School of Science, Dalian Maritime University, 1 Linghai Road, Dalian, Liaoning 116026, P. R. China
| | - Hongbin Ding
- School of Physics, Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, Dalian University of Technology, Dalian 116024, China
| | - Weiqing Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xixi Hu
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
| | - Daiqian Xie
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210023, China
| | - John M C Plane
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Wuhu Feng
- National Centre for Atmospheric Science and School of Earth & Environment, University of Leeds, Leeds LS2 9JT, U.K
| | - Colin M Western
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | | | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| |
Collapse
|
3
|
Kalogerakis KS. A previously unrecognized source of the O 2 Atmospheric band emission in Earth's nightglow. SCIENCE ADVANCES 2019; 5:eaau9255. [PMID: 30906860 PMCID: PMC6426466 DOI: 10.1126/sciadv.aau9255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Earth's night sky continuously produces a faint chemiluminescence known as nightglow. Two prominent nighttime emissions around 90 km are the O2 Atmospheric and the OH Meinel band systems. Despite a plethora of studies since their identification seven decades ago, substantial gaps persist in our understanding of the mechanisms that control them. This report shows that oxygen atoms connect these two emissions: Fast, multiquantum, vibrational-to-electronic relaxation of OH(v) by O atoms activates a pathway that generates O2 Atmospheric band emission. This newly discovered source exhibits a strong altitude dependence and can contribute a majority of the observed O2 Atmospheric band emission when the peaks of the OH and O-atom layers overlap. The new findings call for a reinterpretation of Earth's nightglow emissions and a revision of relevant atmospheric models.
Collapse
|
4
|
Kalogerakis KS, Matsiev D, Cosby PC, Dodd JA, Falcinelli S, Hedin J, Kutepov AA, Noll S, Panka PA, Romanescu C, Thiebaud JE. New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium. ANNALES GEOPHYSICAE 2018; 36:13-24. [PMID: 29503514 PMCID: PMC5833932 DOI: 10.5194/angeo-36-13-2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The question of whether mesospheric OH(υ) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(υ) rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-υ) vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(υ) rotational population distributions. Rapid OH(high-υ) + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-υ) rotational distributions. The effective rotational temperatures of mesospheric OH(υ) are found to deviate from local thermodynamic equilibrium for all observed vibrational levels.
Collapse
Affiliation(s)
| | - Daniel Matsiev
- Center for Geospace Studies, SRI International, Menlo Park, California, USA
| | - Philip C. Cosby
- formerly at: Molecular Physics Laboratory, SRI International, Menlo Park, California, USA
| | - James A. Dodd
- Air Force Research Laboratory (AFRL), Space Vehicles Directorate, Kirtland Air Force Base, New Mexico, USA
| | - Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Jonas Hedin
- Department of Meteorology (MISU), Stockholm University, Stockholm, Sweden
- formerly at: Physical Sciences Division, SRI International, Menlo Park, California, USA
| | - Alexander A. Kutepov
- The Catholic University of America, Washington DC, USA
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Stefan Noll
- Institute for Astro- and Particle Physics, University of Innsbruck, Innsbruck, Austria
- Institute of Physics, University of Augsburg, Augsburg, Germany
- German Remote Sensing Data Center (DFD), German Aerospace Center (DLR), Oberpfaffenhofen, Germany
| | - Peter A. Panka
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Constantin Romanescu
- formerly at: Physical Sciences Division, SRI International, Menlo Park, California, USA
| | - Jérôme E. Thiebaud
- formerly at: Physical Sciences Division, SRI International, Menlo Park, California, USA
- Aeris Technologies, Redwood City, California, USA
| |
Collapse
|
5
|
Pautet PD, Taylor MJ, Pendleton WR, Zhao Y, Yuan T, Esplin R, McLain D. Advanced mesospheric temperature mapper for high-latitude airglow studies. APPLIED OPTICS 2014; 53:5934-5943. [PMID: 25321674 DOI: 10.1364/ao.53.005934] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/28/2014] [Indexed: 06/04/2023]
Abstract
Over the past 60 years, ground-based remote sensing measurements of the Earth's mesospheric temperature have been performed using the nighttime hydroxyl (OH) emission, which originates at an altitude of ∼87 km. Several types of instruments have been employed to date: spectrometers, Fabry-Perot or Michelson interferometers, scanning-radiometers, and more recently temperature mappers. Most of them measure the mesospheric temperature in a few sample directions and/or with a limited temporal resolution, restricting their research capabilities to the investigation of larger-scale perturbations such as inertial waves, tides, or planetary waves. The Advanced Mesospheric Temperature Mapper (AMTM) is a novel infrared digital imaging system that measures selected emission lines in the mesospheric OH (3,1) band (at ∼1.5 μm) to create intensity and temperature maps of the mesosphere around 87 km. The data are obtained with an unprecedented spatial (∼0.5 km) and temporal (typically 30″) resolution over a large 120° field of view, allowing detailed measurements of wave propagation and dissipation at the ∼87 km level, even in the presence of strong aurora or under full moon conditions. This paper describes the AMTM characteristics, compares measured temperatures with values obtained by a collocated Na lidar instrument, and presents several examples of temperature maps and nightly keogram representations to illustrate the excellent capabilities of this new instrument.
Collapse
|
6
|
Hart VP, Doyle TE, Taylor MJ, Carruth BL, Pautet PD, Zhao Y. Three-dimensional tomographic reconstruction of mesospheric airglow structures using two-station ground-based image measurements. APPLIED OPTICS 2012; 51:963-974. [PMID: 22410901 DOI: 10.1364/ao.51.000963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 12/14/2011] [Indexed: 05/31/2023]
Abstract
A new methodology is presented to create two-dimensional (2D) and three-dimensional (3D) tomographic reconstructions of mesospheric airglow layer structure using two-station all-sky image measurements. A fanning technique is presented that produces a series of cross-sectional 2D reconstructions, which are combined to create a 3D mapping of the airglow volume. The imaging configuration is discussed and the inherent challenges of using limited-angle data in tomographic reconstructions have been analyzed using artificially generated imaging objects. An iterative reconstruction method, the partially constrained algebraic reconstruction technique (PCART), was used in conjunction with a priori information of the airglow emission profile to constrain the height of the imaged region, thereby reducing the indeterminacy of the inverse problem. Synthetic projection data were acquired from the imaging objects and the forward problem to validate the tomographic method and to demonstrate the ability of this technique to accurately reconstruct information using only two ground-based sites. Reconstructions of the OH airglow layer were created using data recorded by all-sky CCD cameras located at Bear Lake Observatory, Utah, and at Star Valley, Wyoming, with an optimal site separation of ~100 km. The ability to extend powerful 2D and 3D tomographic methods to two-station ground-based measurements offers obvious practical advantages for new measurement programs. The importance and applications of mesospheric tomographic reconstructions in airglow studies, as well as the need for future measurements and continued development of techniques of this type, are discussed.
Collapse
Affiliation(s)
- Vern P Hart
- Department of Physics, Utah State University, 4415 Old Main Hill, Logan, Utah 84322, USA.
| | | | | | | | | | | |
Collapse
|
7
|
Xu J, Gao H, Smith AK, Zhu Y. Using TIMED/SABER nightglow observations to investigate hydroxyl emission mechanisms in the mesopause region. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016342] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
8
|
Kalogerakis KS, Smith GP, Copeland RA. Collisional removal of OH(X2Π,υ= 9) by O, O2, O3, N2, and CO2. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd015734] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
9
|
Grygalashvyly M, Becker E, Sonnemann GR. Wave mixing effects on minor chemical constituents in the MLT region: Results from a global CTM driven by high-resolution dynamics. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015518] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
10
|
Smith AK, Marsh DR, Mlynczak MG, Mast JC. Temporal variations of atomic oxygen in the upper mesosphere from SABER. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd013434] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
11
|
Burtt KD, Sharma RD. Near-resonant energy transfer from highly vibrationally excited OH to N2. J Chem Phys 2008; 128:124311. [PMID: 18376923 DOI: 10.1063/1.2884343] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The probability per collision P(T) of near-resonant vibration-to-vibration energy transfer (ET) of one quantum of vibrational energy from vibrational levels nu=8 and nu=9 of OH to N(2)(nu=0), OH(nu)+N(2)(0)-->OH(nu-1)+N(2)(1), is calculated in the 100-350 K temperature range. These processes represent important steps in a model that explains the enhanced 4.3 microm emission from CO(2) in the nocturnal mesosphere. The calculated energy transfer is mediated by weak long-range dipole-quadrupole interaction. The results of this calculation are very sensitive to the strength of the two transition moments. Because of the long range of the intermolecular potential, the resonance function, a measure of energy that can be efficiently exchanged between translation and vibration-rotation degrees of freedom, is rather narrow. A narrow resonance function coupled with the large rotational constant of OH is shown to render the results of the calculation very sensitive to the rotational distribution, or the rotational temperature if one exists, of this molecule. The calculations are carried out in the first and second orders of perturbation theory with the latter shown to give ET probabilities that are an order of magnitude larger than the former. The reasons for the difference in magnitude and temperature dependence of the first- and second-order calculations are discussed. The results of the calculations are compared with room temperature measurements as well as with an earlier calculation. Our calculated results are in good agreement with the room temperature measurements for the transfer of vibrational energy for the exothermic OH(nu=9) ET process but are about an order lower than the room temperature measurements for the exothermic OH(nu=8) ET process. The cause of this discrepancy is explored. This calculation does not give the large values of the rate coefficients needed by the model that explains the enhanced 4.3 microm emission from CO(2) in the nocturnal mesosphere.
Collapse
Affiliation(s)
- Kelly D Burtt
- Space Vehicles Directorate (RVBXT), Air Force Research Laboratory, Hanscom Air Force Base, Massachusetts 01731-3010, USA
| | | |
Collapse
|
12
|
Varandas A. Trajectory binning scheme and non-active treatment of zero-point energy leakage in quasi-classical dynamics. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.03.090] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
13
|
Viswanathan R, Dolgos M, Hinde RJ. Quasiclassical trajectory study of the vibrational quenching of hydroxyl radicals through collision with O atoms. J Phys Chem A 2007; 111:783-92. [PMID: 17266218 DOI: 10.1021/jp0667947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The collisional removal of vibrationally excited OH radicals by O atoms is studied by the quasiclassical trajectory method. To evaluate the effect of different topological features on the scattering processes two different global potential energy surfaces, DMBE IV and TU, are used. Results for reactive, exchange, and inelastic scattering probabilities are reported for central collisions (with zero total angular momentum) with a fixed relative translational energy for vibrational levels of OH ranging from nu=1 to v=8. Vibrational state distributions of product molecules are also compared on the two potential energy surfaces. Both surfaces predict higher probabilities for reaction than for exchange or inelastic scattering. The vibrational state distributions of the product diatomic molecules are different on the two surfaces. In particular, the two surfaces give substantially different probabilities for multiquantum OH vibrational relaxation transitions OH(v)+O-->OH(v')+O.
Collapse
Affiliation(s)
- Raji Viswanathan
- Department of Chemistry, Yeshiva University, New York, New York 10033, USA.
| | | | | |
Collapse
|
14
|
Khachatrian A, Dagdigian PJ. Effect of Vibrational Excitation on the Collisional Removal of Free Radicals by Atoms: OH(v=1) + N. J Phys Chem A 2006; 110:3388-92. [PMID: 16526617 DOI: 10.1021/jp0561017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The collisional removal of vibrationally excited OH(upsilon=1) by N(4S) atoms is investigated. The OH radical was prepared by 193 nm photolysis of H2O2, and N(4S) atoms were generated by a microwave discharge in N2 diluted in argon. The concentrations of OH(upsilon=0 and 1) were monitored by laser-induced fluorescence as a function of the time after the photolysis laser pulse. The N(4S) concentration was determined from the OH(upsilon=0) decay rate, using the known rate constant for the OH(upsilon=0) + N(4S) --> H + NO reaction. From comparison of the OH(upsilon=0 and 1) decay rates, the ratio of the rate constant k(upsilon=1)(OH-N) for removal of OH(upsilon=1) in collisions with N(4S) and the corresponding OH(upsilon=0) rate constant, k(upsilon=0)(OH-N) was determined to be 1.61 +/- 0.42, yielding k(upsilon=1)(OH-N) = (7.6 +/- 2.1) x 10(-11) cm3 molecule(-1) s(-1), where the quoted uncertainty (95% confidence limits) includes the uncertainty in k(upsilon=0)(OH-N). Thus, the collisional removal of OH(upsilon=1) by N(4S) atoms is found to be faster than for OH(upsilon=0).
Collapse
Affiliation(s)
- Ani Khachatrian
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
| | | |
Collapse
|
15
|
|
16
|
Abstract
Vibrationally excited O2, OH, and HO2 species have been suggested (J. Phys. Chem. A 2004, 108, 758) to provide clues for explaining the "ozone deficit problem" and "HOx dilemma" in the middle atmosphere under conditions of local thermodynamic disequilibrium (LTD), but the question arises of how much LTD will affect the title ozone sink reactions. Besides providing novel kinetic results, it is shown that LTD tends to disfavor ozone depletion relative to traditional atmospheric modeling under Boltzmann equilibration, which is partly due to competition between the various reactive channels. The calculations also suggest that the title LTD processes can be important sources of highly vibrationally excited O2 in the middle atmosphere. Moreover, LTD is shown to offer an explanation for the fact that some down revision of the O + HO2 rate constant, or the ratio of the O + HO2 to O + OH rate constants, is required to improve agreement between the predictions of traditional modeling and observation. This, in turn, provides significant evidence supporting LTD at such altitudes.
Collapse
Affiliation(s)
- A J C Varandas
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
| |
Collapse
|
17
|
Liu J, Zhang P, Morokuma K, Sharma RD. A new mechanism for the production of highly vibrationally excited OH in the mesosphere: An ab initio study of the reactions of O2(AΣu+3andA′Δu3)+H. J Chem Phys 2005; 122:104315. [PMID: 15836323 DOI: 10.1063/1.1862233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In an attempt to explain the observed nightglow emission from OH(v=10) in the mesosphere that has the energy greater than the exothermicity of the H+O(3) reaction, potential energy surfaces were calculated for reactions of high lying electronic states of O(2)(A (3)Sigma(u) (+) and A' (3)Delta(u)) with atomic hydrogen H((2)S) to produce the ground state products OH((2)Pi)+O((3)P). From collinear two-dimensional scans, several adiabatic and nonadiabatic pathways have been identified. Multiconfigurational single and double excitation configuration interaction calculations show that the adiabatic pathways on a (4)Delta potential surface from O(2)(A' (3)Delta)+H and a (4)Sigma(+) potential surface from O(2)(A (3)Sigma(u) (+))+H are the most favorable, with the zero-point corrected barrier heights of as low as 0.191 and 0.182 eV, respectively, and the reactions are fast. The transition states for these pathways are collinear and early, and the reaction coordinate suggests that the potential energy release of ca. 3.8 eV (larger than the energy required to excite OH to v=10) is likely to favor high vibrational excitation.
Collapse
Affiliation(s)
- Jianjun Liu
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | | | | | | |
Collapse
|
18
|
Smith GP, Copeland RA. Comment on “Are Vibrationally Excited Molecules a Clue for the O3 Deficit Problem and HOx Dilemma in the Middle Atmosphere?”. J Phys Chem A 2005; 109:2698-9; discussion 2700-2. [PMID: 16833576 DOI: 10.1021/jp0405613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gregory P Smith
- Molecular Physics Laboratory, SRI International, Menlo Park, California 94025, USA.
| | | |
Collapse
|
19
|
Varandas AJC. Reply to the Comment on “Are Vibrationally Excited Molecules a Clue for the O3 Deficit Problem and HOx Dilemma in the Middle Atmosphere?”. J Phys Chem A 2005. [DOI: 10.1021/jp040745h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. J. C. Varandas
- Departamento de Quimica, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| |
Collapse
|
20
|
|
21
|
D’Ottone L, Bauer D, Campuzano-Jost P, Fardy M, Hynes AJ. Vibrational deactivation studies of OH X2Π (v = 1–5) by N2and O2. Phys Chem Chem Phys 2004. [DOI: 10.1039/b407297a] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
22
|
Lacoursière J, Dyer MJ, Copeland RA. Temperature dependence of the collisional energy transfer of OH(v=10) between 220 and 310 K. J Chem Phys 2003. [DOI: 10.1063/1.1530581] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|