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Jiang J. Diabatic Valence-Hole Concept. J Phys Chem A 2024; 128:3253-3265. [PMID: 38647413 DOI: 10.1021/acs.jpca.4c00289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
A global diabatization scheme, based on the "valence-hole" concept, has been previously applied to model webs of avoided crossings that exist in four electronic-state symmetry manifolds of C2 (1Πg, 3Πg, 1Σu+, and 3Σu+). Here, this model is extended to the electronically excited states of four more molecules: CN (2Σ+), N2 (3Πu), SiC (3Π), and Si2 (3Πg). Many strangenesses in the spectroscopic observations (e.g., energy level structure, predissociation linewidths, and radiative lifetimes) for all four electronic state systems discussed here are accounted for by this unified model. The key concept of the model is valence-hole electron configurations: 3σ24σ11π45σ2 in CN (2Σ+), 2σg22σu11πu43σg21πg1 in N2 (3Πu), 5σ26σ17σ22π3 in SiC (3Π), and 4σg24σu15σg22πu3 in Si2 (3Πg), all of which have a triply occupied "valence-core" (i.e., 2σg22σu1 or the equivalent). These valence-hole configurations have a nominal bond order of three or higher and correlate with high-energy separated-atom limits with an np ← ns (n = 2, 3) promotion in one of the atomic constituents. On its way to dissociation, the strongly bound diabatic valence-hole state crosses multiple weakly bound or repulsive states, which belong to electron configurations with a completely filled valence-core. These curve crossings between diabatic potentials result in a network of many avoided crossings among multiple electronic states, analogous to the well-studied electronic structure landscape of ionic-covalent crossings in strongly ionic molecules. Considering the unique role of valence-hole states in shaping the global electronic structure, the valence-hole concept should be added to our intuitive framework of chemical bonding.
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Affiliation(s)
- Jun Jiang
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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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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Heays AN, Lewis BR, de Oliveira N, Ubachs W. The spin-forbidden vacuum-ultraviolet absorption spectrum of 14N 15N. J Chem Phys 2019; 151:224305. [PMID: 31837671 DOI: 10.1063/1.5130206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Photoabsorption spectra of 14N15N were recorded at high resolution with a vacuum-ultraviolet Fourier-transform spectrometer fed by synchrotron radiation in the range of 81-100 nm. The combination of high column density (3 × 1017 cm-2) and low temperature (98 K) allowed for the recording of weak spin-forbidden absorption bands' exciting levels of triplet character. The triplet states borrow intensity from 1Πu states of Rydberg and valence character while causing their predissociation. New predissociation linewidths and molecular constants are obtained for the states C3Πu(v = 7, 8, 14, 15, 16, 21), G3Πu(v = 0, 1, 4), and F3Πu(v = 0). The positions and widths of these levels are shown to be well-predicted by a coupled-Schrödinger equation model with empirical parameters based on experimental data on 14N2 and 15N2 triplet levels.
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Affiliation(s)
- A N Heays
- Department of Physics and Astronomy, and LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - B R Lewis
- Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - N de Oliveira
- Synchrotron Soleil, Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette Cedex, France
| | - W Ubachs
- Department of Physics and Astronomy, and LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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4
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Luspay-Kuti A, Mandt K, Jessup KL, Kammer J, Hue V, Hamel M, Filwett R. Photochemistry on Pluto - I. Hydrocarbons and aerosols. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 2017; 472:104-117. [PMID: 31359891 PMCID: PMC6662216 DOI: 10.1093/mnras/stx1362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In light of the recent New Horizons flyby measurements, we present a coupled ion-neutral-photochemistry model developed for simulating the atmosphere of Pluto. Our model results closely match the observed density profiles of CH4, N2 and the C2 hydrocarbons in the altitude range where available New Horizons measurements are most accurate (above ~ 100-200 km). We found a high eddy coefficient of 106 cm2 s-1 from the surface to an altitude of 150 km, and 3 × 106 cm2 s-1 above 150 km for Pluto's atmosphere. Our results demonstrate that C2 hydrocarbons must stick to and be removed by aerosol particles in order to reproduce the C2 profiles observed by New Horizons. Incorporation into aerosols in Pluto's atmosphere is a significantly more effective process than condensation, and we found that condensation alone cannot account for the observed shape of the vertical profiles. We empirically determined the sticking efficiency of C2 hydrocarbons to aerosol particles as a function of altitude, and found that the sticking efficiency of C2 hydrocarbons is inversely related to the aerosol surface area. Aerosols must harden and become less sticky as they age in Pluto's atmosphere. Such hardening with ageing is both necessary and sufficient to explain the vertical profiles of C2 hydrocarbons in Pluto's atmosphere. This result is in agreement with the fundamental idea of aerosols hardening as they age, as proposed for Titan's aerosols.
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Affiliation(s)
- Adrienn Luspay-Kuti
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - Kathleen Mandt
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX 78249, USA
| | - Kandis-Lea Jessup
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - Joshua Kammer
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - Vincent Hue
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - Mark Hamel
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX 78249, USA
| | - Rachael Filwett
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX 78249, USA
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5
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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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Adams SF, Williamson JM. Spectroscopic study of N2(b1Πu, ν = 8) by atmospheric-pressure resonant-enhanced multiphoton ionization and fluorescence detection. J Phys Chem A 2013; 117:13535-42. [PMID: 24047155 DOI: 10.1021/jp407412t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A spectroscopic analysis of the strongly perturbed N2(b(1)Πu, ν = 8) state has been conducted, accounting for b(1)Πu(ν = 8) ← X (1)Σg(+)(ν = 0) transitions, for the first time, up to J' = 20. A novel laser spectroscopy technique, using a combination of resonant-enhanced multiphoton ionization and fluorescence detection at atmospheric pressure, avoids the severe effects of perturbation reported in past extreme vacuum ultraviolet absorption experiments that produced weak and unusable spectra for the ν = 8 level. The R, Q, and P branches of the three-photon absorption transition b(1)Πu(ν = 8) ← X(1)Σg(+)(ν = 0) were fit, allowing rotational term energy assignment up to J' = 20 and molecular constants to be determined. Evidence of the previously suspected perturbation in b(1)Πu(ν = 8) is clear in this data, with significant Λ-type doubling at higher J' along with an anomalous negative value determined for the centrifugal distortion coefficient.
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Affiliation(s)
- Steven F Adams
- Air Force Research Laboratory, Wright-Patterson AFB , Ohio 45433, United States
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Mandt KE, Gell DA, Perry M, Hunter Waite J, Crary FA, Young D, Magee BA, Westlake JH, Cravens T, Kasprzak W, Miller G, Wahlund JE, Ågren K, Edberg NJT, Heays AN, Lewis BR, Gibson ST, de la Haye V, Liang MC. Ion densities and composition of Titan's upper atmosphere derived from the Cassini Ion Neutral Mass Spectrometer: Analysis methods and comparison of measured ion densities to photochemical model simulations. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012je004139] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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8
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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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9
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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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10
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Wu CYR, Judge DL, Tsai MH, Lin YC, Yih TS, Lo JI, Fung HS, Lee YY, Lewis BR, Heays AN, Gibson ST. Experimental verification of strong rotational dependence of fluorescence and predissociation yield in the b 1Πu(v = 1) level of 14N2. J Chem Phys 2012; 136:044301. [DOI: 10.1063/1.3676781] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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11
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On the strong and selective isotope effect in the UV excitation of N2 with implications toward the nebula and Martian atmosphere. Proc Natl Acad Sci U S A 2011; 108:6020-5. [PMID: 21441106 DOI: 10.1073/pnas.1102767108] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Isotopic effects associated with molecular absorption are discussed with reference to natural phenomena including early solar system processes, Titan and terrestrial atmospheric chemistry, and Martian atmospheric evolution. Quantification of the physicochemical aspects of the excitation and dissociation processes may lead to enhanced understanding of these environments. Here we examine a physical basis for an additional isotope effect during photolysis of molecular nitrogen due to the coupling of valence and Rydberg excited states. The origin of this isotope effect is shown to be the coupling of diabatic electronic states of different bonding nature that occurs after the excitation of these states. This coupling is characteristic of energy regimes where two or more excited states are nearly crossing or osculating. A signature of the resultant isotope effect is a window of rapid variation in the otherwise smooth distribution of oscillator strengths vs. frequency. The reference for the discussion is the numerical solution of the time dependent Schrödinger equation for both the electronic and nuclear modes with the light field included as part of the Hamiltonian. Pumping is to all extreme UV dipole-allowed, valence and Rydberg, excited states of N(2). The computed absorption spectra are convoluted with the solar spectrum to demonstrate the importance of including this isotope effect in planetary, interstellar molecular cloud, and nebular photochemical models. It is suggested that accidental resonance with strong discrete lines in the solar spectrum such as the CIII line at 97.703 nm can also have a marked effect.
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12
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Vieitez MO, Ivanov TI, Sprengers JP, Lange CAD, Ubachs W, Lewis BR, Stark G. Quantum-interference effects in the o1Πu(v=1)∼b1Πu(v=9) Rydberg–valence complex of molecular nitrogen. Mol Phys 2010. [DOI: 10.1080/00268970701291750] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Huber KP, Chan MC, Stark G, Ito K, Matsui T. N(2) band oscillator strengths at near-threshold energies. J Chem Phys 2009; 131:084301. [PMID: 19725610 DOI: 10.1063/1.3211309] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Band oscillator strengths for 58 bands in the near-threshold region of N(2), i.e., from 116 200 to 125 400 cm(-1), are derived from measured band-integrated optical depths. The complexity of the absorption spectrum demands that the measurements be carried out on rotationally cold supersonic jet expansions. The column density N in the absorbing path of the jet cannot be measured directly. Instead, the room temperature f values of selected calibration bands are used to convert the band-integrated optical depths of the jet-cooled calibration bands to preliminary column densities [N], which, plotted as a function of jet reservoir pressure p, scatter around a straight line passing through the origin of the graph. From the slope of the line, first estimates of the effective column density N can be derived for any value of p. Second estimates are obtained by repeating the same procedure using ab initio calculated f values based on the work of Spelsberg and Meyer [J. Chem. Phys. 115, 6438 (2001)]. Depending on the jet configuration, the two estimates differ by 3%-15%; their average is accepted as the best approximation to N. The derived band oscillator strengths are compatible with ab initio results of Spelsberg and Meyer and reproduce the observations reasonably well, even where two or more transitions combine in the formation of complex band structures. They also clarify the analysis of the absorption spectrum in the region of the 7p(0) complex [Jungen, Huber, Jungen, and Stark, J. Chem. Phys. 118, 4517 (2003)] and lead to a plausible interpretation of the spectrum in the 124 680-124 880 cm(-1) range. As a result, the lowest three vibronic levels of both the 3(')d(')sigma and the 4(')s(')sigma core excited states have now been identified.
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Affiliation(s)
- Klaus P Huber
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, ON, K1A 0R6, Canada.
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14
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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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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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16
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Ndome H, Hochlaf M, Lewis BR, Heays AN, Gibson ST, Lefebvre-Brion H. Sign reversal of the spin-orbit constant for the C Π3u state of N2. J Chem Phys 2008; 129:164307. [DOI: 10.1063/1.2990658] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Lewis BR, Baldwin KGH, Sprengers JP, Ubachs W, Stark G, Yoshino K. Optical observation of the C, 3ssigma(g)F3, and 3ppi(u)G3 3Pi(u) states of N2. J Chem Phys 2008; 129:164305. [PMID: 19045264 DOI: 10.1063/1.2990655] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High-resolution laser-based one extreme-ultraviolet (EUV)+one UV two-photon ionization spectroscopy and EUV photoabsorption spectroscopy have been employed to study spin-forbidden (3)Pi(u)-X (1)Sigma(g) (+)(v,0) transitions in (14)N(2) and (15)N(2). Levels of the C (3)Pi(u) valence and 3ssigma(g)F(3) and 3ppi(u)G(3) (3)Pi(u) Rydberg states are characterized, either through their direct optical observation, or, indirectly, through their perturbative effects on the (1)Pi(u) and (1)Sigma(u) (+) states, which are accessible in dipole-allowed transitions. Optical observation of the G(3)-X(0,0) and (1,0) transitions is reported for the first time, together with evidence for six new vibrational levels of the C state. Following the recent observation of the F(3)-X(0,0) transition at rotational resolution [J. P. Sprengers et al., J. Chem. Phys. 123, 144315 (2005)], the F(3)(v=1) level is found to be responsible for a local perturbation in the rotational predissociation pattern of the b(') (1)Sigma(u) (+)(v=4) state. Despite their somewhat fragmentary nature, these new observations provide a valuable database on the (3)Pi(u) states of N(2) and their interactions which will help elucidate the predissociation mechanisms for the nitrogen molecule.
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Affiliation(s)
- B R Lewis
- Research School of Physical Sciences and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
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18
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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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19
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Stark G, Lewis BR, Heays AN, Yoshino K, Smith PL, Ito K. Oscillator strengths and line widths of dipole-allowed transitions in N214 between 89.7 and 93.5nm. J Chem Phys 2008; 128:114302. [DOI: 10.1063/1.2834933] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Wu CYR, Fung HS, Chang KY, Singh TS, Mu XL, Nee JB, Chiang SY, Judge DL. Fluorescence excitation spectra of the bΠu1, b′Σu+1, cnΠu1, and cn′Σu+1 states of N2 in the 80–100nm region. J Chem Phys 2007; 127:084314. [PMID: 17764255 DOI: 10.1063/1.2768923] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Fluorescence excitation spectra produced through photoexcitation of N(2) using synchrotron radiation in the spectral region between 80 and 100 nm have been studied. Two broadband detectors were employed to simultaneously monitor fluorescence in the 115-320 nm and 300-700 nm regions, respectively. The peaks in the vacuum ultraviolet fluorescence excitation spectra are found to correspond to excitation of absorption transitions from the ground electronic state to the b (1)Pi(u), b(') (1)Sigma(u) (+), c(n) (1)Pi(u) (with n=4-8), c(n) (') (1)Sigma(u) (+) (with n=5-9), and c(4) (')(v('))(1)Sigma(u) (+) (with v(')=0-8) states of N(2). The relative fluorescence production cross sections for the observed peaks are determined. No fluorescence has been produced through excitation of the most dominating absorption features of the b-X transition except for the (1,0), (5,0), (6,0), and (7,0) bands, in excellent agreement with recent lifetime measurements and theoretical calculations. Fluorescence peaks, which correlate with the long vibrational progressions of the c(4) (') (1)Sigma(u) (+) (with v(')=0-8) and the b(') (1)Sigma(u) (+) (with v(') up to 19), have been observed. The present results provide important information for further unraveling of complicated and intriguing interactions among the excited electronic states of N(2). Furthermore, solar photon excitation of N(2) leading to the production of c(4) (')(0) may provide useful data required for evaluating and analyzing dayglow models relevant to the interpretation of c(4) (')(0) in the atmospheres of Earth, Jupiter, Saturn, Titan, and Triton.
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Affiliation(s)
- C Y Robert Wu
- Space Sciences Center, University of Southern California, Los Angeles, California 90089-1341, USA.
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Lewis BR, Gibson ST, Sprengers JP, Ubachs W, Johansson A, Wahlström CG. Lifetime and predissociation yield of N214bΠu1(v=1) revisited: Effects of rotation. J Chem Phys 2005; 123:236101. [PMID: 16392953 DOI: 10.1063/1.2137722] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Stark G, Huber KP, Yoshino K, Smith PL, Ito K. Oscillator strength and linewidth measurements of dipole-allowed transitions in N214 between 93.5 and 99.5nm. J Chem Phys 2005; 123:214303. [PMID: 16356044 DOI: 10.1063/1.2134703] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Line oscillator strengths in 16 electric dipole-allowed bands of 14N2 in the 93.5-99.5 nm (106,950-100,500 cm(-1)) region have been measured at an instrumental resolution of 6.5 x 10(-4) nm (0.7 cm(-1)). The transitions terminate on vibrational levels of the 3psigma 1Sigma u (+), 3ppi 1Pi u, and 3ssigma 1Pi u Rydberg states and of the b' 1Sigma u (+) and b 1Pi u valence states. The J dependences of band f values derived from the experimental line f values are reported as polynomials in J'(J'+1) and are extrapolated to J'=0 in order to facilitate comparisons with results of coupled-Schrodinger-equation calculations that do not take into account rotational interactions. Most bands in this study reveal a marked J dependence of the f values and/or display anomalous P-, Q- and R-branch intensity patterns. These patterns should help inform future spectroscopic models that incorporate rotational effects, and these are critical for the construction of realistic atmospheric radiative transfer models. Linewidth measurements are reported for four bands. Information provided by the J dependences of the experimental linewidths should be of use in the development of a more complete understanding of the predissociation mechanisms in N2.
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Affiliation(s)
- G Stark
- Department of Physics, Wellesley College, Wellesley, Massachusetts 02481, USA.
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