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Wu Y, Hochlaf M, Schatz GC. Modeling of collision-induced excitation and quenching of atomic nitrogen. J Chem Phys 2024; 161:014104. [PMID: 38949582 DOI: 10.1063/5.0215553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/06/2024] [Indexed: 07/02/2024] Open
Abstract
Excited atomic nitrogen atoms play an important role in plasma formation in hypersonic shock-waves, as happens during spacecraft reentry and other high velocity vehicle applications. In this study, we have thoroughly studied collision induced excitation associated with two colliding nitrogen atoms in the N(4S), N(2D), and N(2P) states at collision energies up to 6 eV, using time-independent scattering calculations to determine cross sections and temperature-dependent rate coefficients. The calculations are based on potential curves and couplings determined in earlier multireference configuration interaction calculations with large basis sets, and the results are in good agreement with experiments where comparisons are possible. To properly consider the spin-orbit coupling matrix, we have developed a scaling method for treating transitions between different fine-structure components that only require calculations with two coupled states, and with this, we define accurate degeneracy factors for determining cross sections and rate coefficients that include all states. The results indicate that both spin-orbit and derivative coupling effects can play important roles in collisional excitation and quenching, and that although derivative coupling is always much stronger than spin-orbit, there are many transitions where only spin-orbit can contribute. As part of this, we identify two distinct pathways associated with N(2P) relaxation and one Auger-like mechanism leading to two N(2D) that could be important at high temperatures.
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Affiliation(s)
- Yanze Wu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes, 77454 Champs sur Marne, France
| | - George C Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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2
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Gelfand N, Komarova K, Remacle F, Levine RD. Nonadiabatic quantum dynamics explores non-monotonic photodissociation branching of N 2 into the N( 4S) + N( 2D) and N( 4S) + N( 2P) product channels. Phys Chem Chem Phys 2024; 26:3274-3284. [PMID: 38197167 DOI: 10.1039/d3cp04854c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Vacuum ultraviolet (VUV) photodissociation of N2 molecules is a source of reactive N atoms in the interstellar medium. In the energy range of VUV optical excitation of N2, the N-N triple bond cleavage leads to three types of atoms: ground-state N(4S) and excited-state N(2P) and N(2D). The latter is the highest reactive and it is believed to be the primary participant in reactions with hydrocarbons in Titan's atmosphere. Experimental studies have observed a non-monotonic energy dependence and non-statistical character of the photodissociation of N2. This implies different dissociation pathways and final atomic products for different wavelength regions in the sunlight spectrum. We here apply ab initio quantum chemical and nonadiabatic quantum dynamical techniques to follow the path of an electronic state from the excitation of a particular singlet 1Σ+u and 1Πu vibronic level of N2 to its dissociation into different atomic products. We simulate dynamics for two isotopomers of the nitrogen molecule, 14N2 and 14N15N for which experimental data on the branching are available. Our computations capture the non-monotonic energy dependence of the photodissociation branching ratios in the energy range 108 000-116 000 cm-1. Tracing the quantum dynamics in a bunch of electronic states enables us to identify the key components that determine the efficacy of singlet to triplet population transfer and therefore predissociation lifetimes and branching ratios for different energy regions.
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Affiliation(s)
- Natalia Gelfand
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| | - Ksenia Komarova
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| | - Francoise Remacle
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
- Theoretical Physical Chemistry, UR MolSys B6c, University of Liège, B4000 Liège, Belgium
| | - R D Levine
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
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3
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Minaev BF, Panchenko OO, Minaeva VA, Ågren H. Triplet state harvesting and search for forbidden transition intensity in the nitrogen molecule. Front Chem 2022; 10:1005684. [PMID: 36329857 PMCID: PMC9623019 DOI: 10.3389/fchem.2022.1005684] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/22/2022] [Indexed: 02/29/2024] Open
Abstract
Triplet excited states of the N2 molecule play an important role in electric discharges through air or liquid nitrogen accompanied by various afterglows. In the rarefied upper atmosphere, they produce aurora borealis and participate in other energy-transfer processes connected with atmospheric photochemistry and nightglow. In this work, we present spin-orbit coupling calculations of the intensity of various forbidden transitions, including the prediction of the electric dipole transition moment of the new1 3 Σ g - ← A 3 Σ u + band, which is strongly prohibited by the (+|-) selection rule, the new spin-induced magneticB ' 3 Σ u - ← A 3 Σ u + transition, magnetic and electric quadrupole transitions for the B3Πg← X 1 Σ g + Wilkinson band, and the Lyman-Birge-Hopfield a1Πg ← X1Σg transition. Also, two other far-UV singlet-singlet quadrupole transitions are calculated for the first time, namely, the Dressler-Lutz a"1Σg +-X1Σg + and the less studied z1Δg-X1Σg + weak transitions.
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Affiliation(s)
- B. F Minaev
- Department of chemistry and nanomaterial sciences, Bohdan Khmelnytsky National University, Cherkasy, Ukraine
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - O. O Panchenko
- Department of chemistry and nanomaterial sciences, Bohdan Khmelnytsky National University, Cherkasy, Ukraine
| | - V. A Minaeva
- Department of chemistry and nanomaterial sciences, Bohdan Khmelnytsky National University, Cherkasy, Ukraine
| | - H Ågren
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
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5
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Qin Z, Zhao J, Liu L. Radiative transition probabilities between low-lying electronic states of N 2. Mol Phys 2019. [DOI: 10.1080/00268976.2018.1562579] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Zhi Qin
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, People's Republic of China
| | - Junming Zhao
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, People's Republic of China
| | - Linhua Liu
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, People's Republic of China
- School of Energy and Power Engineering, Shandong University, Qingdao, People's Republic of China
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6
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Musiał M, Lupa Ł, Kucharski SA. Equation-of-motion coupled cluster method for the description of the high spin excited states. J Chem Phys 2016; 144:154105. [PMID: 27389207 DOI: 10.1063/1.4946031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The equation-of-motion (EOM) coupled cluster (CC) approach in the version applicable for the excitation energy(EE) calculations has been formulated for high spin components. The EE-EOM-CC scheme based on the restricted Hartree-Fock reference and standard amplitude equations as used in the Davidson diagonalization procedure yields the singlet states. The triplet and higher spin components require separate amplitude equations. In the case of quintets, the relevant equations are much simpler and easier to solve. Out of 26 diagrammatic terms contributing to the R1 and R2 singlet equations in the case of quintets, only R2 operator survives with 5 diagrammatic terms present. In addition all terms engaging three body elements of the similarity transformed Hamiltonian disappear. This indicates a substantial simplification of the theory. The implemented method has been applied to the pilot study of the excited states of the C2 molecule and quintet states of C and Si atoms.
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Affiliation(s)
- Monika Musiał
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland
| | - Łukasz Lupa
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland
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7
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Tennyson J, Little DA. Computed bound and continuum electronic states of the nitrogen molecule. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158403002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Patanen M, Nicolas C, Linguerri R, Simões G, Travnikova O, Liu XJ, Hochlaf M, Bozek JD, Miron C. High-resolution photoelectron spectroscopy with angular selectivity - a tool to probe valence-Rydberg states and couplings in HCl(+). J Phys Chem A 2014; 118:4975-81. [PMID: 25007894 DOI: 10.1021/jp504505e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to strong electron correlation effects and electron coupling with nuclear motion, the molecular inner-valence photoionization is still a challenge in electron spectroscopy, resulting in several interesting phenomena such as drastic changes of angular dependencies, spin-orbit induced predissociation, and complex interplay between adiabatic and nonadiabatic transitions. We investigated the excited electronic states of HCl(+) in the binding energy range 27.5-30.5 eV using synchrotron radiation based high-resolution inner-valence photoelectron spectroscopy with angular resolution and interpreted the observations with the help of ab initio calculations. Overlapping electronic states in this region were disentangled through the analysis of photoelectron emission anisotropies. For instance, a puzzling transition, which does not seem to obey either an adiabatic or a nonadiabatic picture, has been identified at ∼28.6 eV binding energy. By this study, we show that ultrahigh-resolution photoelectron spectroscopy with angular selectivity represents a powerful tool to probe the highly excited ionic molecular electronic states and their intricate couplings.
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Affiliation(s)
- M Patanen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France
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Abbiche K, Marakchi K, Komiha N, Francisco J, Linguerri R, Hochlaf M. Accurate theoretical spectroscopy of the lowest electronic states of CP radical. Mol Phys 2014. [DOI: 10.1080/00268976.2014.901567] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Maatouk A, Ben Houria A, Yazidi O, Jaidane N, Hochlaf M. Electronic states of MgO: Spectroscopy, predissociation, and cold atomic Mg and O production. J Chem Phys 2010; 133:144302. [DOI: 10.1063/1.3498900] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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