1
|
Craciunescu L, Liane EM, Kirrander A, Paterson MJ. Excited-state van der Waals potential energy surfaces for the NO A2Σ+ + CO2X1Σg+ collision complex. J Chem Phys 2023; 159:124303. [PMID: 38127380 DOI: 10.1063/5.0165769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/06/2023] [Indexed: 12/23/2023] Open
Abstract
Excited state van der Waals (vdW) potential energy surfaces (PESs) of the NO A2Σ+ + CO2X1Σg+ system are thoroughly investigated using coupled cluster theory and complete active space perturbation theory to second order (CASPT2). First, it is shown that pair natural orbital coupled cluster singles and doubles with perturbative triples yields comparable accuracy compared to CCSD(T) for molecular properties and vdW-minima at a fraction of computational cost of the latter. Using this method in conjunction with highly diffuse basis sets and counterpoise correction for basis set superposition error, the PESs for different intermolecular orientations are investigated. These show numerous vdW-wells, interconnected for all geometries except one, with a maximum depth of up to 830 cm-1; considerably deeper than those on the ground state surface. Multi-reference effects are investigated with CASPT2 calculations. The long-range vdW-surfaces support recent experimental observations relating to rotational energy transfer due the anisotropy in the potentials.
Collapse
Affiliation(s)
- Luca Craciunescu
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, United Kingdom
| | - Eirik M Liane
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OX1 3QZ Oxford, United Kingdom
| | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OX1 3QZ Oxford, United Kingdom
| | - Martin J Paterson
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, United Kingdom
| |
Collapse
|
2
|
Bridgers A, Urquilla JA, Im J, Petit AS. Theoretical Study of the Photochemical Mechanisms of the Electronic Quenching of NO( A2Σ +) with CH 4, CH 3OH, and CO 2. J Phys Chem A 2023; 127:7228-7240. [PMID: 37552562 PMCID: PMC10476188 DOI: 10.1021/acs.jpca.3c03981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/15/2023] [Indexed: 08/10/2023]
Abstract
The electronic quenching of NO(A2Σ+) with molecular partners occurs through complex non-adiabatic dynamics that occurs on multiple coupled potential energy surfaces. Moreover, the propensity for NO(A2Σ+) electronic quenching depends heavily on the strength and nature of the intermolecular interactions between NO(A2Σ+) and the molecular partner. In this paper, we explore the electronic quenching mechanisms of three systems: NO(A2Σ+) + CH4, NO(A2Σ+) + CH3OH, and NO(A2Σ+) + CO2. Using EOM-EA-CCSD calculations, we rationalize the very low electronic quenching cross-section of NO(A2Σ+) + CH4 as well as the outcomes observed in previous NO + CH4 photodissociation studies. Our analysis of NO(A2Σ+) + CH3OH suggests that it will undergo facile electronic quenching mediated by reducing the intermolecular distance and significantly stretching the O-H bond of CH3OH. For NO(A2Σ+) + CO2, intermolecular attractions lead to a series of low-energy ON-OCO conformations in which the CO2 is significantly bent. For both the NO(A2Σ+) + CH3OH and NO(A2Σ+) + CO2 systems, we see evidence of the harpoon mechanism and low-energy conical intersections between NO(A2Σ+) + M and NO(X2Π) + M. Overall, this work provides the first detailed theoretical study on the NO(A2Σ+) + M potential energy surface of each of these systems and will inform future velocity map imaging experiments.
Collapse
Affiliation(s)
- Aerial
N. Bridgers
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United
States
| | - Justin A. Urquilla
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United
States
| | - Julia Im
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United
States
| | - Andrew S. Petit
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United
States
| |
Collapse
|
3
|
Soulié C, Paterson MJ. Molecular properties and excited state van der Waals potentials in the NO A 2Σ + + O 2 XΣ g- collision complex. Phys Chem Chem Phys 2022; 24:7983-7993. [PMID: 35311872 DOI: 10.1039/d1cp05286a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We characterize NO A2Σ+ + O2 X3Σg- van der Waals (vdW) Potential Energy Surface (PES) with RHF/RCCSD(T) and CASSCF/CASPT2 calculations. To do this, we first assess our computational setup to properly represent the individual molecular properties of O2 X3Σg-, NO X2Π, and NO A2Σ+. Specifically, we show that highly augmented basis sets are necessary to properly represent the NO A2Σ+ polarizability. Then, we optimize different vdW geometries, and provide BSSE corrected plots of the quartet vdW PES. The surfaces show a confined channel at a distance of approximately 6 Å with a depth of at least 20 cm-1 that we believe is caused by NO A2Σ+ hyper-polarizability. At shorter distances, the channel is connected to a vdW basin centered around the O-N O-O linear geometry with an inter-molecular separation of 4.3 Å, and a depth of 95 cm-1 at the RCCSD(T) level. A CASPT2 scan along the linear geometry show that this vdW basin exists on both the doublet and quartet excited surfaces. These results infer the existence of a collision complex between NO A2Σ+ and O2 X3Σg-, as predicted by earlier experiments.
Collapse
Affiliation(s)
- Clément Soulié
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, Scotland, UK.
| | - Martin J Paterson
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, Scotland, UK.
| |
Collapse
|
4
|
Guardado JL, Urquilla JA, Kidwell NM, Petit AS. Reactive quenching of NO (A 2Σ +) with H 2O leads to HONO: a theoretical analysis of the reactive and nonreactive electronic quenching mechanisms. Phys Chem Chem Phys 2022; 24:26717-26730. [DOI: 10.1039/d2cp04214b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study, we develop a mechanistic understanding of the pathways for nonreactive and reactive electronic quenching of NO (A2Σ+) with H2O. In doing so, we identify a photochemical mechanism for HONO production in the upper atmosphere.
Collapse
Affiliation(s)
- José L. Guardado
- Department of Chemistry and Biochemistry, California State University – Fullerton, Fullerton, CA 92834-6866, USA
| | - Justin A. Urquilla
- Department of Chemistry and Biochemistry, California State University – Fullerton, Fullerton, CA 92834-6866, USA
| | - Nathanael M. Kidwell
- Department of Chemistry, The College of William and Mary, Williamsburg, VA 23187-8795, USA
| | - Andrew S. Petit
- Department of Chemistry and Biochemistry, California State University – Fullerton, Fullerton, CA 92834-6866, USA
| |
Collapse
|
5
|
Guardado JL, Hood DJ, Luong K, Kidwell NM, Petit AS. Stereodynamic Control of Collision-Induced Nonadiabatic Dynamics of NO ( A2Σ +) with H 2, N 2, and CO: Intermolecular Interactions Drive Collision Outcomes. J Phys Chem A 2021; 125:8803-8815. [PMID: 34606268 DOI: 10.1021/acs.jpca.1c05653] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Intermolecular interactions, stereodynamics, and coupled potential energy surfaces (PESs) all play a significant role in determining the outcomes of molecular collisions. A detailed knowledge of such processes is often essential for a proper interpretation of spectroscopic observations. For example, nitric oxide (NO), an important radical in combustion and atmospheric chemistry, is commonly quantified using laser-induced fluorescence on the A2Σ+ ← X2Π transition band. However, the electronic quenching of NO (A2Σ+) with other molecular species provides alternative nonradiative pathways that compete with fluorescence. While the cross sections and rate constants of NO (A2Σ+) electronic quenching have been experimentally measured for a number of important molecular collision partners, the underlying photochemical mechanisms responsible for the electronic quenching are not well understood. In this paper, we describe the development of high-quality PESs that provide new physical insights into the intermolecular interactions and conical intersections that facilitate the branching between the electronic quenching and scattering of NO (A2Σ+) with H2, N2, and CO. The PESs are calculated at the EOM-EA-CCSD/d-aug-cc-pVTZ//EOM-EA-CCSD/aug-cc-pVDZ level of theory, an approach that ensures a balanced treatment of the valence and Rydberg electronic states and an accurate description of the open-shell character of NO. Our PESs show that H2 is incapable of electronically quenching NO (A2Σ+) at low collision energies; instead, the two molecules will likely undergo scattering. The PESs of NO (A2Σ+) with N2 and CO are highly anisotropic and demonstrate evidence of electron transfer from NO (A2Σ+) into the lowest unoccupied molecular orbital of the collision partner, that is, the harpoon mechanism. In the case of ON + CO, the PES becomes strongly attractive at longer intermolecular distances and funnels population to a conical intersection between NO (A2Σ+) + CO and NO (X2Π) + CO. In contrast, for ON + N2, the conical intersection is preceded by an ∼0.40 eV barrier. Overall, our work shines new light into the impact of coupled PESs on the nonadiabatic dynamics of open-shell systems.
Collapse
Affiliation(s)
- José L Guardado
- Department of Chemistry and Biochemistry, California State University-Fullerton, Fullerton, California 92834-6866, United States
| | - David J Hood
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Kate Luong
- Department of Chemistry and Biochemistry, California State University-Fullerton, Fullerton, California 92834-6866, United States
| | - Nathanael M Kidwell
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Andrew S Petit
- Department of Chemistry and Biochemistry, California State University-Fullerton, Fullerton, California 92834-6866, United States
| |
Collapse
|
6
|
Fletcher JD, Lanfri L, Ritchie GAD, Hancock G, Islam M, Richmond G. Time-resolved observations of vibrationally excited NO X 2Π ( v') formed from collisional quenching of NO A 2Σ + ( v = 0) by NO X 2Π: evidence for the participation of the NO a 4Π state. Phys Chem Chem Phys 2021; 23:20478-20488. [PMID: 34498634 DOI: 10.1039/d1cp03360c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved observations have been made of the formation of vibrationally excited NO X 2Π (v') following collisional quenching of NO A 2Σ+ (v = 0) by NO X 2Π (v = 0). Two time scales are observed, namely a fast production rate consistent with direct formation from the quenching of the electronically excited NO A state, together with a slow component, the magnitude and rate of formation of which depend upon NO pressure. A reservoir state formed by quenching of NO A 2Σ+ (v = 0) is invoked to explain the observations, and the available evidence points to this state being the first electronically excited state of NO, a 4Π. The rate constant for quenching of the a 4Π state to levels v' = 11-16 by NO is measured as (8.80 ± 1.1) × 10-11 cm3 molecule-1 s-1 at 298 K where the error quoted is two standard deviations, and from measurements of the increased formation of high vibrational levels of NO(X) by the slow process we estimate a lower limit for the fraction of self-quenching collisions of NO A 2Σ+ (v = 0) which lead to NO a 4Π as 19%.
Collapse
Affiliation(s)
- James D Fletcher
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, UK.
| | - Lucia Lanfri
- Universidad Nacional de Córdoba, INFIQC CONICET, Córdoba, Argentina
| | - Grant A D Ritchie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, UK.
| | - Gus Hancock
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, UK.
| | - Meez Islam
- School of Science and Engineering, Teesside University, Middlesbrough, TS1 3BA, UK
| | - Graham Richmond
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, UK.
| |
Collapse
|
7
|
Amedro D, Bunkan AJC, Dillon TJ, Crowley JN. Characterization of two photon excited fragment spectroscopy (TPEFS) for HNO 3 detection in gas-phase kinetic experiments. Phys Chem Chem Phys 2021; 23:6397-6407. [PMID: 33704308 DOI: 10.1039/d1cp00297j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have developed and tested two-photon excited fragment spectroscopy (TPEFS) for detecting HNO3 in pulsed laser photolysis kinetic experiments. Dispersed (220-330 nm) and time-dependent emission at (310 ± 5) nm following the 193 nm excitation of HNO3 in N2, air and He was recorded and analysed to characterise the OH(A2Σ) and NO(A2Σ+) electronic excited states involved. The limit of detection for HNO3 using TPEFS was ∼5 × 109 molecule cm-3 (at 60 torr N2 and 180 μs integration time). Detection of HNO3 using the emission at (310 ± 5 nm) was orders of magnitude more sensitive than detection of NO and NO2, especially in the presence of O2 which quenches NO(A2Σ+) more efficiently than OH(A2Σ). While H2O2 (and possibly HO2) could also be detected by 193 nm TPEFS, the relative sensitivity (compared to HNO3) was very low. The viability of real-time TPEFS detection of HNO3 using emission at (310 ± 5) nm was demonstrated by monitoring HNO3 formation in the reaction of OH + NO2 and deriving the rate coefficient, k2. The value of k2 obtained at 293 K and pressures of 50-200 torr is entirely consistent with that obtained by simultaneously measuring the OH decay and is in very good agreement with the most recent literature values.
Collapse
Affiliation(s)
- Damien Amedro
- Division of Atmospheric Chemistry, Max Planck-Institut für Chemie, 55128, Mainz, Germany.
| | | | | | | |
Collapse
|
8
|
Blackshaw KJ, Quartey NK, Korb RT, Hood DJ, Hettwer CD, Kidwell NM. Imaging the nonreactive collisional quenching dynamics of NO (A 2Σ +) radicals with O 2 (X 3Σ g -). J Chem Phys 2019; 151:104304. [PMID: 31521090 DOI: 10.1063/1.5109112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nitric oxide (NO) radicals are ubiquitous chemical intermediates present in the atmosphere and in combustion processes, where laser-induced fluorescence is extensively used on the NO (A2Σ+ ← X2Π) band to report on fuel-burning properties. However, accurate fluorescence quantum yields and NO concentration measurements are impeded by electronic quenching of NO (A2Σ+) to NO (X2Π) with colliding atomic and molecular species. To improve predictive combustion models and develop a molecular-level understanding of NO (A2Σ+) quenching, we report the velocity map ion images and product state distributions of NO (X2Π, v″ = 0, J″, Fn, Λ) following nonreactive collisional quenching of NO (A2Σ+) with molecular oxygen, O2 (X3Σg -). A novel dual-flow pulse valve nozzle is constructed and implemented to carry out the NO (A2Σ+) electronic quenching studies and to limit NO2 formation. The isotropic ion images reveal that the NO-O2 system evolves through a long-lived NO3 collision complex prior to formation of products. Furthermore, the corresponding total kinetic energy release distributions support that O2 collision coproducts are formed primarily in the c1Σu - electronic state with NO (X2Π, v″ = 0, J″, Fn, Λ). The product state distributions also indicate that NO (X2Π) is generated with a propensity to occupy the Π(A″) Λ-doublet state, which is consistent with the NO π* orbital aligned perpendicular to nuclear rotation. The deviations between experimental results and statistical phase space theory simulations illustrate the key role that the conical intersection plays in the quenching dynamics to funnel population to product rovibronic levels.
Collapse
Affiliation(s)
- K Jacob Blackshaw
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Naa-Kwarley Quartey
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Robert T Korb
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - David J Hood
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Christian D Hettwer
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Nathanael M Kidwell
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| |
Collapse
|
9
|
Winner JD, West NA, McIlvoy MH, Buen ZD, Bowersox RD, North SW. The role of near resonance electronic energy transfer on the collisional quenching of NO (A2Σ+) by C6H6 and C6F6 at low temperature. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2017.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
10
|
Few J, Fletcher JD, Hancock G, Redmond JL, Ritchie GAD. An FTIR emission study of the products of NO A 2Σ + (v = 0, 1) + O 2 collisions. Phys Chem Chem Phys 2017; 19:11289-11298. [PMID: 28418047 DOI: 10.1039/c7cp00904f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Collisional quenching of NO A2Σ+ (v = 0, 1) by O2 has been studied through the detection of vibrationally excited products by time-resolved Fourier transform infrared emission spectroscopy. Non-reactive quenching of NO A2Σ+ (v = 0) produces a vibrational distribution in NO X2Π which has been quantified for v = 2-22, and is found to be bimodal. The results are consistent with two quenching channels. The first forms the ground X3Σ or low-lying a 1Δg electronic state of O2 with a distribution including high vibrational levels of NO X2Π which is slightly hotter than statistical. Two possibilities are identified for the second channel. The first, with a similar quantum yield to that producing higher vibrational levels, forms a highly electronically excited state, such as O2 c1Σ, with low vibrational levels in NO X2Π which are inverted with a distribution resembling that resulting from a sudden or harpoon mechanism. The second is that ground state oxygen is formed with low vibrational energy partitioned into NO X2Π. In addition, vibrationally excited NO2 is observed, but at intensities which indicate that it is formed in low quantum yield. Quantitatively unobservable processes (defined as those which do not form ground state NO (v ≥ 2)) are found to have a branching ratio of at most 25 ± 5%. The results are compared with those of previous studies and the most consistent interpretation suggests that dissociation of O2 to form ground state O(3P) atoms and ground vibrational state NO X2Π (v = 0) is the main reactive process rather than NO2 formation. Qualitatively similar results are seen for the quenching of NO A2Σ+ (v = 1).
Collapse
Affiliation(s)
- Julian Few
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
| | | | | | | | | |
Collapse
|
11
|
Sharples TR, Luxford TFM, Townsend D, McKendrick KG, Costen ML. Rotationally inelastic scattering of NO(A(2)Σ(+)) + Ar: Differential cross sections and rotational angular momentum polarization. J Chem Phys 2015; 143:204301. [PMID: 26627953 DOI: 10.1063/1.4935962] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the implementation of a new crossed-molecular beam, velocity-map ion-imaging apparatus, optimized for collisions of electronically excited molecules. We have applied this apparatus to rotational energy transfer in NO(A(2)Σ(+), v = 0, N = 0, j = 0.5) + Ar collisions, at an average energy of 525 cm(-1). We report differential cross sections for scattering into NO(A(2)Σ(+), v = 0, N' = 3, 5, 6, 7, 8, and 9), together with quantum scattering calculations of the differential cross sections and angle dependent rotational alignment. The differential cross sections show dramatic forward scattered peaks, together with oscillatory behavior at larger scattering angles, while the rotational alignment moments are also found to oscillate as a function of scattering angle. In general, the quantum scattering calculations are found to agree well with experiment, reproducing the forward scattering and oscillatory behavior at larger scattering angles. Analysis of the quantum scattering calculations as a function of total rotational angular momentum indicates that the forward scattering peak originates from the attractive minimum in the potential energy surface at the N-end of the NO. Deviations in the quantum scattering predictions from the experimental results, for scattering at angles greater than 10°, are observed to be more significant for scattering to odd final N'. We suggest that this represents inaccuracies in the potential energy surface, and in particular in its representation of the difference between the N- and O-ends of the molecule, as given by the odd-order Legendre moments of the surface.
Collapse
Affiliation(s)
- Thomas R Sharples
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Thomas F M Luxford
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Dave Townsend
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Kenneth G McKendrick
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Matthew L Costen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| |
Collapse
|
12
|
Sánchez-González R, Eveland WD, West NA, Mai CLN, Bowersox RDW, North SW. Low-temperature collisional quenching of NO A2Σ+(v′ = 0) by NO(X2Π) and O2 between 34 and 109 K. J Chem Phys 2014; 141:074313. [DOI: 10.1063/1.4892980] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- R. Sánchez-González
- Department of Chemistry, Texas A&M University, 3012 TAMU, College Station, Texas 77843, USA
| | - W. D. Eveland
- Department of Chemistry, Texas A&M University, 3012 TAMU, College Station, Texas 77843, USA
| | - N. A. West
- Department of Chemistry, Texas A&M University, 3012 TAMU, College Station, Texas 77843, USA
| | - C. L. N. Mai
- Department of Aerospace Engineering, Texas A&M University, 3141 TAMU, College Station, Texas 77843, USA
| | - R. D. W. Bowersox
- Department of Aerospace Engineering, Texas A&M University, 3141 TAMU, College Station, Texas 77843, USA
| | - S. W. North
- Department of Chemistry, Texas A&M University, 3012 TAMU, College Station, Texas 77843, USA
| |
Collapse
|
13
|
Few J, Hancock G. Rate constants for collisional quenching of NO (A(2)Σ(+), v = 0) by He, Ne, Ar, Kr, and Xe, and infrared emission accompanying rare gas and impurity quenching. Phys Chem Chem Phys 2014; 16:11047-53. [PMID: 24777304 DOI: 10.1039/c4cp00740a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The quenching rates of NO (A(2)Σ(+), v = 0) with He, Ne, Ar, Kr and Xe have been studied at room temperature by measurements of the time dependence of the fluorescence decay following laser excitation. The rates are slow, with upper limits of rate constants determined as between 1.2 and 2.0 × 10(-14) cm(3) molecule(-1) s(-1), considerably lower than those reported before in the literature. Such slow rates can be markedly influenced by impurities such as O2 and H2O which have quenching rate constants close to gas kinetic values. Time resolved Fourier transform infrared emission has been used to observe the products of the quenching processes with the rare gases and with impurities. For He, Ne Ar and Kr there is no difference within experimental error of the populations in NO (X(2)Π v ≥ 2) produced with and without rare gas present, but the low quantum yields of such quenching (of the order of 5% for an atmosphere of rare gas) preclude quantitative information on the quantum states being obtained. For quenching by Xe the collisional formation of electronically excited Xe atoms dominates the emission at early times. Vibrationally excited NO (X(2)Π, v) and products of reactive quenching are observed in the presence of O2 and H2O.
Collapse
Affiliation(s)
- Julian Few
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
| | | |
Collapse
|
14
|
Sánchez-González R, Bowersox RDW, North SW. Vibrationally excited NO tagging by NO(A²∑⁺) fluorescence and quenching for simultaneous velocimetry and thermometry in gaseous flows. OPTICS LETTERS 2014; 39:2771-2774. [PMID: 24784099 DOI: 10.1364/ol.39.002771] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present measurements demonstrating simultaneous determination of velocity and temperature using a variant of the Vibrationally Excited Nitric Oxide Monitoring (VENOM) technique that does not employ NO2. The variant is based on tagging by electronic excitation of NO in the A²∑(1/2)⁺ (v'=0)←X2Π1/2(v''=0) band and subsequent formation of vibrationally excited NO(X2Π) by spontaneous emission and collisional quenching. Sequential planar laser-induced fluorescence imaging of the nascent NO(X2Π, v''=1) was used to obtain spatially resolved average streamwise velocity and rotational/translational temperature. The temperature determination using this approach extends the applicability of the VENOM technique to low-density, high-speed flows, where slow thermalization of the tagged molecules represents a limiting factor.
Collapse
|
15
|
Burgos Paci MA, Few J, Gowrie S, Hancock G. Products of the quenching of NO A 2Σ+ (v = 0) by N2O and CO2. Phys Chem Chem Phys 2013; 15:2554-64. [PMID: 23296078 DOI: 10.1039/c2cp43878j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Collisional quenching of NO A (2)Σ(+) (v = 0) by N(2)O and CO(2) has been studied through measurements of vibrationally excited products by time resolved Fourier transform infrared emission. In both cases vibrationally excited NO X (2)Π (v) is seen and quantified in levels v≥ 2 with distributions which are close to statistical. However the quantum yields to produce these levels are markedly different for the two quenchers. For CO(2) such quenching accounts for only ca. 26% of the total: for N(2)O it is ca. 85%. Far more energy is seen in the internal modes of the CO(2) product than those of N(2)O. The results are rationalised in terms of cleavage of the N(2)-O bond being dominant in the latter case, with either a similar O atom production or a specific channel producing almost exclusively NO in low vibrational levels (v = 0,1) for quenching by CO(2). Minor reactive channels yielding NO(2) are seen in both cases, and O((1)D) is observed with low quantum yield in the reaction with N(2)O. The results are discussed in terms of previous models of the quenching processes, and are consistent with the very high yield of NO X (2)Π (v = 0) previously observed by laser induced fluorescence for quenching of NO A (2)Σ(+) (v = 0) by CO(2).
Collapse
|
16
|
Patnaik AK, Roy S, Gord JR, Lucht RP, Settersten TB. Effects of collisions on electronic-resonance-enhanced coherent anti-Stokes Raman scattering of nitric oxide. J Chem Phys 2009; 130:214304. [DOI: 10.1063/1.3137106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
17
|
Settersten TB, Patterson BD, Humphries WH. Radiative lifetimes of NO A [sup 2]Σ[sup +](v[sup ʹ]=0,1,2) and the electronic transition moment of the A [sup 2]Σ[sup +]−X [sup 2]Π system. J Chem Phys 2009. [DOI: 10.1063/1.3227520] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
|