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Chebbi W, Derbel N, Alijah A, Cours T. UV-spectrum and photodecomposition of peroxynitrous acid in the troposphere. Phys Chem Chem Phys 2023; 26:123-129. [PMID: 38059643 DOI: 10.1039/d3cp04580c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
The UV spectrum of peroxynitrous acid, HOONO, was computed at the B3LYP/AVTZ and MCSCF/AVTZ levels using the fewest switches surface hopping algorithm. Due to large-amplitude vibrational motions of this molecule, the maxima in the simulated spectra are displaced from the positions of vertical excitations. The three lowest excited electronic singlet states, which are all repulsive, can be reached by UV absorption. The photolysis products are determined, and the photolysis rate constant is provided for the first time. We found that near the tropopause the photolysis rate constant J ≈ 6 × 10-4 s-1, exceeds that for thermal decomposition by two orders of magnitude. The photolysis lifetime is about 30 minutes. Thus, photolysis is an important process and should be included in atmospheric models.
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Affiliation(s)
- Wiem Chebbi
- LSAMA, Laboratoire de Spectroscopie Atomique, Moléculaire et Applications, Department of Physics, University Tunis - El Manar, 1060 Tunis, Tunisia
- GSMA, Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, University of Reims Champagne-Ardenne, 51100 Reims, France.
| | - Najoua Derbel
- LSAMA, Laboratoire de Spectroscopie Atomique, Moléculaire et Applications, Department of Physics, University Tunis - El Manar, 1060 Tunis, Tunisia
| | - Alexander Alijah
- GSMA, Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, University of Reims Champagne-Ardenne, 51100 Reims, France.
| | - Thibaud Cours
- GSMA, Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, University of Reims Champagne-Ardenne, 51100 Reims, France.
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2
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Winiberg FAF, Chao W, Caravan RL, Markus CR, Sander SP, Percival CJ. A white cell based broadband transient UV-vis absorption spectroscopy with pulsed laser photolysis reactors for chemical kinetics under variable temperatures and pressures. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:114103. [PMID: 37943165 DOI: 10.1063/5.0164733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/14/2023] [Indexed: 11/10/2023]
Abstract
UV-vis spectroscopy is widely used for kinetic studies in physical chemistry, as species' absolute cross-sections are usually less sensitive to experimental conditions (i.e., temperature and pressure). Here, we present the design and characterization of a multipass UV-vis absorption spectroscopy white cell coupled to a pulsed-laser photolysis flow reactor. The glass reactor was designed to facilitate studies of gas phase chemical reactions over a range of conditions (239-293 K and 10-550 Torr). Purged windows mitigate contamination from chemical precursors and photolysis products. We report the measured impact of this purging on temperature uniformity and the absorption length and present some supporting flow calculations. The combined optical setup is unique and enables the photolysis laser to be coaligned with a well-defined absorption pathlength probe beam. This alignment leverages the use of one long-pass filter to increase the spectrum flatness and increase the light intensity vs other systems that use two dichroic mirrors. The probe beam is analyzed with a dual exit spectrograph, customized to split the light between an intensified CCD and photomultiplier tube, enabling simultaneous spectrum and single wavelength detection. This multipass system yields a pathlength of ∼450 cm and minimum observable concentrations of ∼3.7 × 1011 molecule cm-3 (assuming cross-sections ∼1.2 × 10-17 cm2). The temperature profile across the reaction region is ±2 K, defined by the worst-case temperature of 239 K, validated by measurements of the N2O4 equilibrium constant. Finally, the system is implemented to study the simplest Criegee intermediate, demonstrating the instrument performance and advantages of simultaneous spectrum and temporal profile measurements.
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Affiliation(s)
- Frank A F Winiberg
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, USA
| | - Wen Chao
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, USA
| | - Rebecca L Caravan
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, USA
| | - Charles R Markus
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, USA
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, USA
| | - Stanley P Sander
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, USA
| | - Carl J Percival
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, USA
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3
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Caracciolo A, San Vicente Veliz JC, Lu D, Guo H, Meuwly M, Minton TK. Experimental and Theoretical Studies of Hyperthermal N + O 2 Collisions. J Phys Chem A 2023; 127:8834-8848. [PMID: 37843300 DOI: 10.1021/acs.jpca.3c04516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
The dynamics of hyperthermal N(4S) + O2 collisions were investigated both experimentally and theoretically. Crossed molecular beams experiments were performed at an average center-of-mass (c.m.) collision energy of ⟨Ecoll⟩ = 77.5 kcal mol-1, with velocity- and angle-resolved product detection by a rotatable mass spectrometer detector. Nonreactive (N + O2) and reactive (NO + O) product channels were identified. In the c.m. reference frame, the nonreactively scattered N atoms and reactively scattered NO molecules were both directed into the forward direction with respect to the initial direction of the reagent N atoms. On average, more than 90% of the available energy (⟨Eavl⟩ = 77.5 kcal mol-1) was retained in translation of the nonreactive products (N + O2), whereas a much smaller fraction of the available energy for the reactive pathway (⟨Eavl⟩ = 109.5 kcal mol-1) went into translation of the NO + O products, and the distribution of translational energies for this channel was broad, indicating extensive internal excitation in the nascent NO molecules. The experimentally derived c.m. translational energy and angular distributions of the reactive products suggested at least two dynamical pathways to the formation of NO + O. Quasiclassical trajectory (QCT) calculations were performed with a collision energy of Ecoll = 77 kcal mol-1 using two sets of potential energy surfaces, denoted as PES-I and PES-II, and these theoretical results were compared to each other and to the experimental results. PES-I is a reproducing kernel Hilbert space (RKHS) representation of multireference configurational interaction (MRCI) energies, while PES-II is a many-body permutation invariant polynomial (MB-PIP) fit of complete active space second order perturbation (CASPT2) points. The theoretical investigations were both consistent with the experimental suggestion of two dynamical pathways to produce NO + O, where reactive collisions may proceed on the doublet (12A') and quartet (14A') surfaces. When analyzed with this theoretical insight, the experimental c.m. translational energy and angular distributions were in reasonably good agreement with those predicted by the QCT calculations, although minor differences were observed which are discussed. Theoretical translational energy and angular distributions for the nonreactive N + O2 products matched the experimental translational energy and angular distributions almost quantitatively. Finally, relative yields for the nonreactive and reactive scattering channels were determined from the experiment and from both theoretical methods, and all results are in reasonable agreement.
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Affiliation(s)
- Adriana Caracciolo
- Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado 80303, United States
| | | | - Dandan Lu
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Markus Meuwly
- Department of Chemistry, University of Basel, CH-4056 Basel, Switzerland
| | - Timothy K Minton
- Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado 80303, United States
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4
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Lu D, González M, Guo H. Formation of N( 2D) from Hyperthermal Collisions between O( 3P) and NO(X 2Π). J Phys Chem A 2023; 127:8615-8622. [PMID: 37815918 DOI: 10.1021/acs.jpca.3c05680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
Hyperthermal collisions between O(3P) and NO(X2Π) could lead to the formation of the first electronically excited atomic nitrogen (N(2D)), which plays a key role in plasma formation in shock-heated air. This process is facilitated mainly by four doublet states, and to a much lesser extent by two quartet states. In this work, we report quasi-classical trajectory studies of this reactive process using the four analytical adiabatic potential energy surfaces for the doublet states developed previously from fitting high-level ab initio data. The reactions were found to be strongly enhanced by vibrational excitation of the NO reactant, consistent with the existence of potential energy barriers in the exit channel. Despite the large endothermicity of the reaction, the rate coefficient is significant at high temperatures, suggesting a possible role of this reaction in the hyperthermal kinetics in the shock layer of a hypersonic (re)entry vehicle.
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Affiliation(s)
- Dandan Lu
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Miguel González
- Departament de Ciència de Materials i Química Física and IQTC, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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Ndengué S, Quintas-Sánchez E, Dawes R, Blackstone CC, Osborn DL. Temperature Dependence of the Electronic Absorption Spectrum of NO 2. J Phys Chem A 2023. [PMID: 37384555 DOI: 10.1021/acs.jpca.3c02832] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
The nitrogen dioxide (NO2) radical is composed of the two most abundant elements in the atmosphere, where it can be formed in a variety of ways including combustion, detonation of energetic materials, and lightning. Relevant also to smog and ozone cycles, together these processes span a wide range of temperatures. Remarkably, high-resolution NO2 electronic absorption spectra have only been reported in a narrow range below about 300 K. Previously, we reported [ J. Phys. Chem. A 2021, 125, 5519-5533] the construction of quasi-diabatic potential energy surfaces (PESs) for the lowest four electronic states (X̃, Ã, B̃, and C̃) of NO2. In addition to three-dimensional PESs based on explicitly correlated MRCI(Q)-F12/VTZ-F12 ab initio data, the geometry dependence of each component of the dipoles and transition dipoles was also mapped into fitted surfaces. The multiconfigurational time-dependent Hartree (MCTDH) method was then used to compute the 0 K electronic absorption spectrum (from the ground rovibrational initial state) employing those energy and transition dipole surfaces. Here, in an extension of that work, we report an investigation into the effects of elevated temperature on the spectrum, considering the effects of the population of rotationally and vibrationally excited initial states. The calculations are complemented by new experimental measurements. Spectral contributions from hundreds of rotational states up to N = 20 and from 200 individually-characterized vibrational states were computed. A spectral simulation tool was developed that enables modeling the spectrum at various temperatures─by weighting individual spectral contributions via the partition function, or for pure excited initial states, which can be probed via transient absorption spectroscopy. We validate these results against experimental absorption spectroscopy data at high temperatures, as well as via a new measurement from the (1,0,1) initial vibrational state.
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Affiliation(s)
- Steve Ndengué
- ICTP-East African Institute for Fundamental Research, University of Rwanda, Kigali 4285, Rwanda
| | | | - Richard Dawes
- Missouri University of Science and Technology, Rolla, Missouri 65409-0010, United States
| | - Christopher C Blackstone
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
- Department of Chemical Engineering, University of California, Davis, California 95616, United States
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Rana R, Thorpe JH, Stanton JF. An interesting case of symmetry breaking in the absence of symmetry: the bicarbonate radical (HCO 3). Mol Phys 2022. [DOI: 10.1080/00268976.2022.2144518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Rohit Rana
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - James H. Thorpe
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - John F. Stanton
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, FL, USA
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Changala B, Genossar N, Baraban JH. Franck-Condon spectra of unbound and imaginary-frequency vibrations via correlation functions: a branch-cut free, numerically stable derivation. J Chem Phys 2022; 157:124102. [DOI: 10.1063/5.0112217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular electronic spectra can be represented in the time domain as auto-correlation functions of the initial vibrational wavepacket. We present a derivation of the harmonic vibrational auto-correlation function that is valid for both real and imaginary harmonic frequencies. The derivation rests on Lie algebra techniques that map otherwise complicated exponential operator arithmetic to simpler matrix formulae. The expressions for the zero- and finite-temperature harmonic auto-correlation functions have been carefully structured both to be free of branch-cut discontinuities and to remain numerically stable with finite-precision arithmetic. Simple extensions correct the harmonic Franck-Condon approximation for the lowest-order anharmonic and Herzberg-Teller effects. Quantitative simulations are shown for several examples, including the electronic absorption spectra of F2, HOCl, CH2NH, and NO2.
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Affiliation(s)
- Bryan Changala
- Harvard-Smithsonian Center for Astrophysics, United States of America
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Lu D, Truhlar DG, Guo H. Reactive and Nonreactive Collisions between NO(X 2Π) and O( 3P) under Hyperthermal Conditions. J Phys Chem A 2022; 126:4277-4285. [PMID: 35749611 DOI: 10.1021/acs.jpca.2c02735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quasiclassical trajectory calculations are performed for hyperthermal collisions between NO(X2Π) and O(3P) on recently developed potential energy surfaces for the lowest doublet and quartet states of the NO2 system. Three product channels are investigated, and their branching fractions are in reasonably good agreement with the recent crossed molecular beam study at 84 kcal/mol of collision energy. The dominant inelastic channel has a strong forward scattering bias and a high translational energy distribution with limited internal excitation in the scattered NO. The exchange channel has significantly higher NO internal excitation and is also forward biased. The abstraction channel producing internally excited O2 has the smallest branching fraction and a broader angular distribution also with a forward peak. The angular and translational energy distributions in the three channels are consistent with experiment, but the agreement is not always quantitative. The sources of the differences are discussed. Finally, the impact of NO vibrational excitation on the reactive channels and the corresponding rate coefficients are reported.
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Affiliation(s)
- Dandan Lu
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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Soto J, Algarra M. Electronic Structure of Nitrobenzene: A Benchmark Example of the Accuracy of the Multi-State CASPT2 Theory. J Phys Chem A 2021; 125:9431-9437. [PMID: 34677962 PMCID: PMC8573753 DOI: 10.1021/acs.jpca.1c04595] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
The electronic structure
of nitrobenzene (C6H5NO2) has been
studied by means of the complete active
space self-consistent field (CASSCF) and multi-state second-order
perturbation (MS-CASPT2) methods. To this end, an active space of
20 electrons distributed in 17 orbitals has been selected to construct
the reference wave function. In this work, we have calculated the
vertical excitation energies and the energy barrier for the dissociation
of the molecule on the ground state into phenyl and nitrogen dioxide.
After applying the corresponding vibrational corrections to the electronic
energies, it is demonstrated that the MS-CASPT2//CASSCF values obtained
in this work yield an excellent agreement between calculated and experimental
data. In addition, other active spaces of lower size have been applied
to the system in order to check the active space dependence in the
results.
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Affiliation(s)
- Juan Soto
- Department of Physical Chemistry, Faculty of Science, University of Málaga, Málaga 29071, Spain
| | - Manuel Algarra
- Department of Inorganic Chemistry, Faculty of Science, University of Málaga, Málaga 29071, Spain
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