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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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2
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Jiang P, Lu L, Liu M, Gao H. Multi-channel photodissociation dynamics of 14N 2 in its b' 1Σ+u( ν = 20) state. Phys Chem Chem Phys 2022; 24:11544-11551. [PMID: 35506911 DOI: 10.1039/d2cp01148d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
b' 1Σ+u(ν = 20) is the first vibronic state above the dissociation limit N(2D3/2,5/2) + N(2D3/2,5/2) of 14N2 that has been observed in the absorption spectrum. It provides a unique opportunity for studying the multi-channel photodissociation dynamics of 14N2, particularly the competition between the spin-forbidden and spin-allowed photodissociation channels. Here, photofragment excitation (PHOFEX) and (1VUV + 1'UV) photoionization spectra of 14N2 in the b' 1Σ+u(ν = 20) state and the time-slice velocity-map ion (TS-VMI) images at each individual rotational levels are collected by using a vacuum ultraviolet (VUV) pump-VUV probe scheme. It is found that the spin-forbidden channels N(4S) + N(2D3/2,5/2) and N(4S) + N(2P1/2,3/2) are competitive with the spin-allowed channel N(2D3/2,5/2) + N(2D3/2,5/2) at low rotational levels, while quickly become undetectable as the rotational quantum number J increases. At high rotational levels, only the spin-allowed channel N(2D3/2,5/2) + N(2D3/2,5/2) can be observed, supporting previous theoretical modeling. Channel-resolved partial predissociation rate constants (PPRCs) are calculated by combining branching ratios in this study and total predissociation rate constants (TPRCs) from previous absorption spectroscopic measurements. PPRCs for dissociation into channels N(4S) + N(2D3/2,5/2) and N(4S) + N(2P1/2,3/2) are almost independent of J, while those of N(2D3/2,5/2) + N(2D3/2,5/2) show complicated rotational dependence. Possible coupling schemes between b' 1Σ+u(ν = 20) and the high lying 1Πu and 3Πu states are analyzed, which provides deep insight into the multi-channel photodissociation dynamics of 14N2 in a high energy range.
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Affiliation(s)
- Pan Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liya Lu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Liu M, Jiang P, Cheng M, Gao H. Vacuum ultraviolet photoexcitation and photofragment spectroscopic studies of 14N 15N between 109000 and 117500 cm -1. J Chem Phys 2021; 155:234305. [PMID: 34937384 DOI: 10.1063/5.0072604] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this study, we employed a newly built time-slice velocity-map ion imaging setup, equipped with two tunable vacuum ultraviolet (VUV) laser sources, to obtain the first comprehensive high-resolution photoexcitation and photofragment excitation spectra of 14N15N in the VUV photon energy range 109 000-117 500 cm-1. The spectroscopic simulation program PGOPHER was used to analyze the rotationally resolved spectra. Band origins, rotational constants, and isotope shifts compared with those of 14N2 have been obtained for 31 electric-dipole-allowed vibrational states of 14N15N in the aforementioned energy range. These spectroscopic parameters are found to depend on the vibrational quantum number irregularly. Systematic perturbations of the rotational transition energies and predissociation rates within individual absorption bands have also been observed. These are proved to be caused by the strong homogeneous interactions between the valence b'1Σu + state and the Rydberg cn ' 1Σu + states, and between the valence b1Πu states and the Rydberg o3 1Πu states. Heterogeneous interactions between the Rydberg cn 1Πu states and cn ' 1Σu + states also play an important role.
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Affiliation(s)
- Min Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Pan Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Min Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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4
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Jiang P, Chi X, Qi W, Zhu Q, Cheng M, Gao H. Rotational dependence of the branching ratios and fragment angular distributions for the photodissociation of 12C 16O in the Rydberg 4p(2) and 5p(0) complex region (92.84-93.37 nm). Phys Chem Chem Phys 2019; 21:14376-14386. [PMID: 30742166 DOI: 10.1039/c8cp07620k] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
12C16O shows complicated absorption structures in the wavelength range of 92.84-93.37 nm caused by the mutual interactions among the Rydberg 4p(2) and 5p(0) complexes, and several diffuse valence states. Here, we systematically measured the branching ratios and fragment angular distributions for the photodissociation of 12C16O in the wavelength range using our mini-time-slice velocity-map imaging (mini-TSVMI) setup and a tunable vacuum ultraviolet (VUV) laser radiation source generated by the two-photon resonance-enhanced four-wave mixing scheme. Various patterns of rotational dependence for the photodissociation branching ratios have been observed for different vibronic states, and they are found to be consistent with previous spectroscopic investigations, revealing the complicated coupling schemes and predissociation dynamics in this region. Irregular angular distributions of the photofragments have been observed, especially in the Rydberg 5p(0) complex region. This has been attributed to the simultaneous excitation of multiple states with different symmetries in this region. The newly observed underlying continuum in the Rydberg 5p(0) complex region has been directly detected in the present study, and it is found to be of 1Σ+ symmetry and dissociates predominantly into the C(3P) + O(3P) channel. This study generally confirms the results of previous spectroscopic studies from a different perspective, and adds new knowledge for understanding the complicated predissociation dynamics of 12C16O in the titled wavelength range.
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Affiliation(s)
- Pan Jiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoping Chi
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenke Qi
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qihe Zhu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Min Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
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5
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Chang YC, Liu K, Kalogerakis KS, Ng CY, Jackson WM. Branching Ratios of the N( 2D 03/2) and N( 2D 05/2) Spin-Orbit States Produced in the State-Selected Photodissociation of N 2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS). J Phys Chem A 2019; 123:2289-2300. [PMID: 30628443 DOI: 10.1021/acs.jpca.8b11691] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Branching ratios for N(2D03/2) and N(2D05/2) produced by predissociation of state selected excited nitrogen molecules in the vacuum ultraviolet region have been measured for the first time. The quantum numbers of the excited nitrogen molecule are defined by selective excitation of the nitrogen molecule in the Franck-Condon region from the ground electronic, 1Σg+, vibrational, v″, and rotational, J″ state to an excited Eu', v', J' state with a tunable vacuum ultraviolet, VUV1, laser. The neutral atoms produced by predissociation from this excited state are then selectively ionized with a second tunable VUV2 laser. Measurement of the relative populations of these two atoms formed in their spin-orbit states defines the quantum states for the atomic products. This means that the wave functions of the initial state and knowledge of the relative yields define all the experimental parameters for this series of unimolecular reactions. The ions formed by VUV2 are mass analyzed with a time-of-flight mass spectrometer and detected with a time slice velocity ion imaging mass spectrometer. In this manner, we can determine the recoil velocity associated with the predissociation process. Two different techniques are used to determine the spin-orbit ratios, namely, resonant VUV photoionization (RVUV-PI) spectroscopy and total kinetic energy release (TKER) spectroscopy determined from the image produced when the atoms are selectively ionized by VUV2 in the interaction region. The TKER spectra obtained from the lines at 110 296.25 and 110 304.96 cm-1 that couple to a newly discovered autoionization line at 129 529.4255 ± 0.0015 cm-1 prove that the lines observed in this region originate from the N(2D03/2) and N(2D05/2) atoms. Two other lines in this region at 110 286.20 and 110 299.89 cm-1 originate from the nitrogen N(4S03/2) that is photoionized in a 1+ 1 VUV-UV resonant multiphoton ionization process. The spin-orbit branching ratios have been evaluated for valence and Rydberg electronic excited states from 104 129.4 to 118 772.1 cm-1, and it shows that they are independent of the rotational and vibrational quantum numbers. They are not appreciably affected by the symmetry properties of the wave function in the Franck-Condon region of the excited states. In the energy region below 117 153.8 cm-1 the pathways at long internuclear distances appear to determine [N(2D03/2)]/[N(2D05/2)] branching ratios of ∼0.38, ∼0.62, and ∼1.04. At higher energies, TKER and RVUV-PI spectroscopy have been used to show that the average fraction of the N(2D03/2) and N(2D05/2) atoms produced in the spin-allowed channels that produce two N(2D0J) is 0.85 versus 0.15 for spin-forbidden channels. The importance and need for this information for comparison with theory and applications in astrochemistry are briefly discussed.
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Affiliation(s)
- Yih Chung Chang
- Department of Chemistry , University of California , Davis , California 95616 , United States
| | - Kai Liu
- Wuhan Institute of Physics and Mathematics, CAS , Wuhan 430071 , China
| | | | - Cheuk-Yiu Ng
- Department of Chemistry , University of California , Davis , California 95616 , United States
| | - William M Jackson
- Department of Chemistry , University of California , Davis , California 95616 , United States
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6
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Gao H, Ng CY. Quantum state-to-state vacuum ultraviolet photodissociation dynamics of small molecules. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1812290] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Hong Gao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Cheuk-Yiu Ng
- Department of Chemistry, University of California, Davis CA 95616, USA
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7
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Shi X, Gao H, Yin QZ, Chang YC, Wiens RC, Jackson WM, Ng CY. Branching Ratio Measurements of the Predissociation of 12C 16O by Time-Slice Velocity-Map Ion Imaging in the Energy Region from 106 250 to 107 800 cm -1. J Phys Chem A 2018; 122:8136-8142. [PMID: 30231612 DOI: 10.1021/acs.jpca.8b08058] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photodissociation of CO is a fundamental chemical mechanism for mass-independent oxygen isotope fractionation in the early Solar System. Branching ratios of photodissociation channels for individual bands quantitatively yield the trapping efficiencies of atomic oxygen resulting into oxides. We measured the branching ratios for the spin-forbidden and spin-allowed photodissociation channels of 12C16O in the vacuum ultraviolet (VUV) photon energy region from 106 250 to 107 800 cm-1 using the VUV laser time-slice velocity-map imaging photoion technique. The excitations to four 1Π bands and three 1Σ+ bands of 12C16O were identified and investigated. The branching ratios for the product channels C(3P) + O(3P), C(1D) + O(3P), and C(3P) + O(1D) of these predissociative states strongly depend on the electronic and vibrational states of CO being excited. By plotting the branching ratio of the spin-forbidden dissociation channels versus the excitation energy from 102 500 to 110 500 cm-1 that has been measured so far, the global pattern of the 1Π-3Π interaction that plays a key role in the predissociation of CO is revealed and discussed.
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Affiliation(s)
| | - Hong Gao
- Institute of Chemistry , Chinese Academy of Science , Beijing 100190 China
| | | | | | - Roger C Wiens
- Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
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8
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Branching Ratios in Vacuum Ultraviolet Photodissociation of CO and N2: Implications for Oxygen and Nitrogen Isotopic Compositions of the Solar Nebula. ACTA ACUST UNITED AC 2017. [DOI: 10.3847/1538-4357/aa8ee7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Heays A, Lewis B, Gibson S, Stark G, de Oliveira N. Indirect predissociation of highly excited singlet states of N 2. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158403004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Tang X, Gao F, Wang J, Yi H, Zhao S. Nitric oxide decomposition using atmospheric pressure dielectric barrier discharge reactor with different adsorbents. RSC Adv 2014. [DOI: 10.1039/c4ra08447k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
An NO removal rate of 99% and energy efficiency of 99.4 g NO per kW h were obtained on NaY zeolite using the adsorption–desorption and decomposition process in a self-made coaxial cylinder-type dielectric barrier discharge reactor.
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Affiliation(s)
- Xiaolong Tang
- Department of Environmental Engineering
- Civil and Environmental Engineering School
- University of Science and Technology Beijing
- Beijing, P. R. China
| | - Fengyu Gao
- Department of Environmental Engineering
- Civil and Environmental Engineering School
- University of Science and Technology Beijing
- Beijing, P. R. China
| | - Jiangen Wang
- Department of Environmental Engineering
- Civil and Environmental Engineering School
- University of Science and Technology Beijing
- Beijing, P. R. China
| | - Honghong Yi
- Department of Environmental Engineering
- Civil and Environmental Engineering School
- University of Science and Technology Beijing
- Beijing, P. R. China
| | - Shunzheng Zhao
- Department of Environmental Engineering
- Civil and Environmental Engineering School
- University of Science and Technology Beijing
- Beijing, P. R. China
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11
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Muskatel BH, Remacle F, Levine RD. Ultrafast Predissociation Mechanism of the 1Πu States of 14N2 and Its Isotopomers upon Attosecond Excitation from the Ground State. J Phys Chem A 2012; 116:11311-8. [DOI: 10.1021/jp305354h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- B. H. Muskatel
- The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel
| | - F. Remacle
- The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel
- Director FNRS, Department
of Chemistry, B6c, University of Liege, B4000 Liege, Belgium
| | - R. D. Levine
- The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel
- Department of Chemistry
and Biochemistry, Crump Institute for Molecular Imaging,
and Department of Molecular and Medical Pharmacology, University of California, Los Angeles,
California 90095, United States
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12
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Gao H, Song Y, Yang L, Shi X, Yin QZ, Ng CY, Jackson WM. Branching ratio measurements of the predissociation of 12C16O by time-slice velocity-map ion imaging in the energy region from 108,000 to 110,500 cm(-1). J Chem Phys 2012; 137:034305. [PMID: 22830700 DOI: 10.1063/1.4734018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Direct branching ratio measurements of the three lowest dissociation channels of (12)C(16)O that produce C((3)P) + O((3)P), C((1)D) + O((3)P), and C((3)P) + O((1)D) are reported in the vacuum ultraviolet region from 108,000 cm(-1) (92.59 nm) to 110,500 cm(-1) (90.50 nm) using the time-slice velocity-map ion imaging and nonlinear resonant four-wave mixing techniques. Rotationally, resolved carbon ion yield spectra for both (1)Σ(+) and (1)Π bands of CO in this region have been obtained. Our measurements using this technique show that the branching ratio in this energy region, especially the relative percentages of the two spin-forbidden channels, is strongly dependent on the particular electronic and vibrational energy levels of CO that are excited.
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Affiliation(s)
- Hong Gao
- Department of Chemistry, University of California Davis, Davis, California 95616, USA
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13
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Heays AN, Dickenson GD, Salumbides EJ, de Oliveira N, Joyeux D, Nahon L, Lewis BR, Ubachs W. High-resolution Fourier-transform extreme ultraviolet photoabsorption spectroscopy of 14N15N. J Chem Phys 2012; 135:244301. [PMID: 22225150 DOI: 10.1063/1.3672165] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The first comprehensive high-resolution photoabsorption spectrum of (14)N(15)N has been recorded using the Fourier-transform spectrometer attached to the Desirs beamline at the Soleil synchrotron. Observations are made in the extreme ultraviolet and span 100 000-109 000 cm(-1) (100-91.7 nm). The observed absorption lines have been assigned to 25 bands and reduced to a set of transition energies, f values, and linewidths. This analysis has verified the predictions of a theoretical model of N(2) that simulates its photoabsorption and photodissociation cross section by solution of an isotopomer independent formulation of the coupled-channel Schrödinger equation. The mass dependence of predissociation linewidths and oscillator strengths is clearly evident and many local perturbations of transition energies, strengths, and widths within individual rotational series have been observed.
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Affiliation(s)
- A N Heays
- Institute for Lasers, Life and Biophotonics Amsterdam, VU University, Amsterdam, The Netherlands.
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14
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Gao H, Song Y, Yang L, Shi X, Yin Q, Ng CY, Jackson WM. Communication: branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region. J Chem Phys 2011; 135:221101. [PMID: 22168673 DOI: 10.1063/1.3669426] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The first direct branching ratio measurement of the three lowest energy dissociation channels of CO that produce C((3)P) + O((3)P), C((1)D) + O((3)P), and C((3)P) + O((1)D) is reported. Rotational resolved carbon ion yield spectra for two Π bands (W(3sσ)(1)Π (v(') = 3) at 108,012.6 cm(-1) and (1)Π(v(') = 2) at 109,017 cm(-1)) and two Σ bands ((4sσ)(1)Σ(+)(v(') = 4) at 109,452 cm(-1) and (4pσ)(1)Σ(+)(v(') = 3) at 109,485 cm(-1)) of CO were obtained. Our measurements show that the branching ratio in this energy region is strongly dependent on the electronic and vibrational energy but it is independent or just weakly dependent on the parity and rotational energy levels. To our knowledge, this is the first time that the triplet channel producing O((1)D) has been experimentally observed and this is also the first time that a direct measurement of the branching ratio for the different channels in the predissociation of CO in this energy region has been made.
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Affiliation(s)
- Hong Gao
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
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15
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Gao H, Yang L, Pan Y, Zhou J, Ng CY, Jackson WM. Time-sliced velocity-mapped imaging studies of the predissociation of single ro-vibronic energy levels of N2 in the extreme ultraviolet region using vacuum ultraviolet photoionization. J Chem Phys 2011; 135:134319. [PMID: 21992317 DOI: 10.1063/1.3644778] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The predissociation of N(2) from the rotational levels in the o(1)∏(u) (v(') = 2) and b(') (1)Σ(u) (v(') = 8) bands has been studied in the wavenumber (or energy) range from 109 350 cm(-1) (13.5577 eV) to 109 580 cm(-1) (13.5862 eV) by time-sliced velocity-mapped imaging technique with VUV photoionization detection of the fragments. These levels were excited from the ground state of N(2) (X(1)Σ(g) (+), v(") = 0) levels using an unfocused vacuum ultraviolet (VUV) laser via a one-photon process. The same VUV laser is used to ionize the metastable N ((2)D(o)) produced from the predissociation process and the time-sliced velocity-mapped imaging technique is used to determine their velocity and angular distributions. Two different theoretical methods developed, respectively, by Kim et al. [J. Chem. Phys. 125, 133316 (2006) and Zande [J. Chem. Phys. 107, 9447 (1997)] were used to calculate the anisotropic parameters for the predissociation to the channel N((4)S(o)) + N((2)D(o)) to compare with the observed value for each of the rotational levels. Very good agreement with the experimental results was obtained for both methods. Possible predissociation mechanisms were predicted from the measurements and calculations.
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Affiliation(s)
- Hong Gao
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
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16
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Pan Y, Gao H, Yang L, Zhou J, Ng CY, Jackson WM. Communication: Vacuum ultraviolet laser photodissociation studies of small molecules by the vacuum ultraviolet laser photoionization time-sliced velocity-mapped ion imaging method. J Chem Phys 2011; 135:071101. [DOI: 10.1063/1.3626867] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yang Pan
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
| | - Hong Gao
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
| | - Lei Yang
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
| | - Jingang Zhou
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
| | - C. Y. Ng
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
| | - William M. Jackson
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA
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17
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Balucani N, Bergeat A, Cartechini L, Volpi GG, Casavecchia P, Skouteris D, Rosi M. Combined crossed molecular beam and theoretical studies of the N(2D) + CH4 reaction and implications for atmospheric models of Titan. J Phys Chem A 2010; 113:11138-52. [PMID: 19642633 DOI: 10.1021/jp904302g] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dynamics of the H-displacement channel in the reaction N((2)D) + CH(4) has been investigated by the crossed molecular beam (CMB) technique with mass spectrometric detection and time-of-flight (TOF) analysis at five different collision energies (from 22.2 up to 65.1 kJ/mol). The CMB results have identified two distinct isomers as primary reaction products, methanimine and methylnitrene, the yield of which significantly varies with the total available energy. From the derived center-of-mass product angular and translational energy distributions the reaction micromechanisms, the product energy partitioning and the relative branching ratios of the competing reaction channels leading to the two isomers have been obtained. The interpretation of the scattering results is assisted by new ab initio electronic structure calculations of stationary points and product energetics for the CH(4)N ground state doublet potential energy surface. Differently from previous theoretical studies, both insertion and H-abstraction pathways have been found to be barrierless at all levels of theory employed in this work. A comparison between experimental results on the two isomer branching ratio and RRKM estimates, based on the new electronic structure calculations, confirms the highly nonstatistical nature of the N((2)D) + CH(4) reaction, with the production of the CH(3)N isomer dominated by dynamical effects. The implications for the chemical models of the atmosphere of Titan are discussed.
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Affiliation(s)
- Nadia Balucani
- Dipartimento di Chimica, Università degli Studi di Perugia, 06123 Perugia, Italy.
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Liu X, Heays AN, Shemansky DE, Lewis BR, Feldman PD. Analysis of terrestrial thermospheric N2c′41Σu+(0) ∼b′1Σu+(1) −X1Σg+dayglow emission observed by the Far Ultraviolet Spectroscopic Explorer. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd010403] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Salumbides EJ, Khramov A, Ubachs W. High-Resolution 2 + 1 REMPI Study of the a′′1Σg+ State in N2. J Phys Chem A 2009; 113:2383-6. [DOI: 10.1021/jp808698u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- E. J. Salumbides
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - A. Khramov
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - W. Ubachs
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Heays AN, Lewis BR, Stark G, Yoshino K, Smith PL, Huber KP, Ito K. Oscillator strengths and line widths of dipole-allowed transitions in [sup 14]N[sub 2] between 86.0 and 89.7 nm. J Chem Phys 2009; 131:194308. [DOI: 10.1063/1.3257690] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Vieitez MO, Ivanov TI, de Lange CA, Ubachs W, Heays AN, Lewis BR, Stark G. Interactions of the 3pπucΠu1(v=2) Rydberg-complex member in isotopic N2. J Chem Phys 2008; 128:134313. [DOI: 10.1063/1.2883955] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Sprengers JP, Ubachs W, Baldwin KGH. Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2. J Chem Phys 2005; 122:144301. [PMID: 15847517 DOI: 10.1063/1.1869985] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Lifetimes of several (1)Pi(u) states of the three natural isotopomers of molecular nitrogen, (14)N(2), (14)N(15)N, and (15)N(2), are determined via linewidth measurements in the frequency domain. Extreme ultraviolet (XUV)+UV two-photon ionization spectra of the b (1)Pi(u)(v=0-1,5-7) and c(3) (1)Pi(u)(v=0) states of (14)N(2), b (1)Pi(u)(v=0-1,5-6) and c(3) (1)Pi(u)(v=0) states of (14)N(15)N, and b (1)Pi(u)(v=0-7), c(3) (1)Pi(u)(v=0), and o (1)Pi(u)(v=0) states of (15)N(2) are recorded at ultrahigh resolution, using a narrow band tunable XUV-laser source. Lifetimes are derived from the linewidths of single rotationally resolved spectral lines after deconvolution of the instrument function. The observed lifetimes depend on the vibrational quantum number and are found to be strongly isotope dependent.
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Affiliation(s)
- J P Sprengers
- Department of Physics and Astronomy, Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Jamieson CS, Mebel AM, Kaiser RI. A matrix isolation study of the Cs symmetric OCNO(X 2A″) radical. Phys Chem Chem Phys 2005; 7:4089-95. [PMID: 16474873 DOI: 10.1039/b511978b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we report the first experimental detection of the C(s) symmetric nitroformyl radical, OCNO(X 2A'') in a nitrogen-carbon dioxide matrix at 10 K using a Fourier transform infrared spectrometer (FTIR). The nu1 vibrational frequency was observed at 2113 cm(-1). This assignment was confirmed by follow-up experiments using isotopically labeled reactant molecules (15N, 18O, 13C). To synthesize this radical, we irradiated solid nitrogen-carbon dioxide ice mixtures with energetic electrons at 10 K. Suprathermal nitrogen atoms in their electronic ground and/or first electronically excited state were generated via the radiation induced degradation of molecular nitrogen; these atoms could then react with carbon dioxide to eventually yield the nitroformyl radical. We also investigated the kinetics of the formation of the nitroformyl radical and support the arguments with computations on the doublet and quartet OCNO potential energy surfaces (PESs).
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Affiliation(s)
- Corey S Jamieson
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Zhao GB, Hu X, Argyle MD, Radosz M. N Atom Radicals and N2(A3∑u+) Found To Be Responsible for Nitrogen Oxides Conversion in Nonthermal Nitrogen Plasma. Ind Eng Chem Res 2004. [DOI: 10.1021/ie049795z] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gui-Bing Zhao
- Department of Chemical & Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071-3295
| | - Xudong Hu
- Department of Chemical & Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071-3295
| | - Morris D. Argyle
- Department of Chemical & Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071-3295
| | - Maciej Radosz
- Department of Chemical & Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071-3295
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Sprengers JP, Ubachs W, Johansson A, L'Huillier A, Wahlström CG, Lang R, Lewis BR, Gibson ST. Lifetime and predissociation yield of 14N2 b 1Πu(v=1). J Chem Phys 2004; 120:8973-8. [PMID: 15267832 DOI: 10.1063/1.1704640] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The lifetime of the b 1Piu(v=1) state in 14N2 has been determined experimentally using a laser-based pump-probe scheme and an exceptionally long lifetime of 2.61 ns was found. Semiempirical close-coupling calculations of the radiative lifetime, which include Rydberg-valence interactions in the singlet manifold, are consistent with this large value, giving a value of 3.61 ns and suggesting a predissociation yield of approximately 28% for this level of the b state.
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Affiliation(s)
- J P Sprengers
- Department of Physics and Astronomy, Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Sprengers JP, Ubachs W, Baldwin KGH, Lewis BR, Tchang-Brillet WÜL. Extreme ultraviolet laser excitation of isotopic molecular nitrogen: The dipole-allowed spectrum of 15N2 and 14N15N. J Chem Phys 2003. [DOI: 10.1063/1.1589478] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Zhang XG, Armentrout PB. Sequential Bond Energies of Pt(CO)x+ (x = 1 −4) Determined by Collision-Induced Dissociation. Organometallics 2001. [DOI: 10.1021/om010390d] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiao-Guang Zhang
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850
| | - P. B. Armentrout
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850
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Walter CW, Cosby PC, Helm H. Photoexcitation and predissociation intensities of the c′ 1∑u+ (v=3 and 4), c 1∏u (v=3 and 4), and b′ 1∑u+ (v=10, 12, 13, and 15) states of N2. J Chem Phys 2000. [DOI: 10.1063/1.481090] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Swaminathan PK, Strobel DF, Kupperman DG, Kumar CK, Acton L, DeMajistre R, Yee JH, Paxton L, Anderson DE, Strickland DJ, Duff JW. Nitric oxide abundance in the mesosphere/lower thermosphere region: Roles of solar soft X rays, suprathermal N(4S) atoms, and vertical transport. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/97ja03249] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Peterson JR, Le Padellec A, Danared H, Dunn GH, Larsson M, Larson A, Peverall R, Strömholm C, Rosén S, af Ugglas M, van der Zande WJ. Dissociative recombination and excitation of N2+: Cross sections and product branching ratios. J Chem Phys 1998. [DOI: 10.1063/1.475577] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Buijsse B, van der Zande WJ. The predissociation mechanisms of the e 1Πu and the b′ 1Σu+ states of N2. J Chem Phys 1997. [DOI: 10.1063/1.475241] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ajello JM, Ciocca M. Fast nitrogen atoms from dissociative excitation of N2by electron impact. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96je01827] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Buijsse B, Wouters ER. Diagnostic Value of Photofragment Anisotropy Measurements: Predissociation Mechanisms of the e 1 Pi u State of N2. PHYSICAL REVIEW LETTERS 1996; 77:243-246. [PMID: 10062402 DOI: 10.1103/physrevlett.77.243] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Minaev B, Norman P, Jonsson D, Ågren H. Response theory calculations of singlet-triplet transitions in molecular nitrogen. Chem Phys 1995. [DOI: 10.1016/0301-0104(94)00321-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Walter CW, Cosby PC, Helm H. Predissociation quantum yields of singlet nitrogen. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1994; 50:2930-2936. [PMID: 9911235 DOI: 10.1103/physreva.50.2930] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Walter CW, Seifert JA, Peterson JR. Reexamination of the He- 1s2p2 4Pe shape resonance: Details of its properties and a precise electron affinity for He 2 (3)S. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1994; 50:2257-2262. [PMID: 9911137 DOI: 10.1103/physreva.50.2257] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Charge-transfer production of predissociated N2 states. I. The n = 3 Rydberg state region (12.8–14 eV). Chem Phys 1994. [DOI: 10.1016/0301-0104(94)00105-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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