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Wang P, Gong S, Mo Y. Bond dissociation energy of O2 measured by fully state-to-state resolved threshold fragment yield spectra. J Chem Phys 2024; 160:164302. [PMID: 38647301 DOI: 10.1063/5.0207288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024] Open
Abstract
We have determined the bond dissociation energy of O2 by measuring fully state-to-state resolved threshold fragment yield spectra in the XUV energy region, O2X3Σg-,N″,J″→O(PJ3)+O(S1o3)/O(S2o5). Our results have yielded a bond dissociation energy value of 41 269.19 ± 0.10 cm-1, which is consistent with previous measurements but exhibits a significantly lower uncertainty, approximately five times smaller. It is noteworthy that this study is the first to simultaneously achieve fine structure state resolution for the parent O2 molecule and spin-orbit state resolution for the O(3PJ) fragments in the measurement of O2 bond dissociation energy. As a result, our findings have established a solid foundation for the obtained data.
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Affiliation(s)
- Peng Wang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Shiyan Gong
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Yuxiang Mo
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
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2
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Wang P, Gong S, Li Y, Mo Y. Bond dissociation energy of N2 measured by state-to-state resolved threshold fragment yield spectra. J Chem Phys 2024; 160:014304. [PMID: 38174795 DOI: 10.1063/5.0187003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
The precise determination of the bond dissociation energy of N2 is crucial for thermochemistry database and theoretical calculations. However, there has been ongoing debate regarding its exact value. In this study, we used the velocity map imaging method combined with an extreme ultraviolet laser to measure the threshold fragment yield (TFY) spectra of N2 in the N(2D) + N(2D) photodissociation channels. By integrating the signals within a small circular area on the fragment velocity map images, we were able to obtain TFY spectra at nine different dissociation thresholds. These spectra are rotational state-resolved for the N2(J″) molecules and spin-orbit state-resolved for the dissociation channels involving N(2D) fragments. By employing the Wigner threshold law to simulate the TFY spectra and conducting statistical analysis on the comprehensive dataset, we determined the N2 bond dissociation energy to be 78 691.09 ± 0.15 cm-1. This work now places N2 among the few diatomic molecules with bond dissociation energies measured at sub-wavenumber precision.
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Affiliation(s)
- Peng Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Shiyan Gong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yixuan Li
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yuxiang Mo
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
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Tantardini C, Oganov AR. Thermochemical electronegativities of the elements. Nat Commun 2021; 12:2087. [PMID: 33828104 PMCID: PMC8027013 DOI: 10.1038/s41467-021-22429-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/16/2021] [Indexed: 02/01/2023] Open
Abstract
Electronegativity is a key property of the elements. Being useful in rationalizing stability, structure and properties of molecules and solids, it has shaped much of the thinking in the fields of structural chemistry and solid state chemistry and physics. There are many definitions of electronegativity, which can be roughly classified as either spectroscopic (these are defined for isolated atoms) or thermochemical (characterizing bond energies and heats of formation of compounds). The most widely used is the thermochemical Pauling's scale, where electronegativities have units of eV-1/2. Here we identify drawbacks in the definition of Pauling's electronegativity scale-and, correcting them, arrive at our thermochemical scale, where electronegativities are dimensionless numbers. Our scale displays intuitively correct trends for the 118 elements and leads to an improved description of chemical bonding (e.g., bond polarity) and thermochemistry.
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Affiliation(s)
- Christian Tantardini
- Skolkovo Institute of Science and Technology, Bolshoi Boulevard 30, Moscow, 121025, Russian Federation.
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 630128, Kutateladze 18, Novosibirsk, Russian Federation.
| | - Artem R Oganov
- Skolkovo Institute of Science and Technology, Bolshoi Boulevard 30, Moscow, 121025, Russian Federation.
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Feller D. Estimating the intrinsic limit of the Feller-Peterson-Dixon composite approach when applied to adiabatic ionization potentials in atoms and small molecules. J Chem Phys 2017; 147:034103. [DOI: 10.1063/1.4993625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hogreve H. Metastable homonuclear diatomic trications X23+ for elements X from the first three rows of the periodic table. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Meng Q, Mo Y. Predissociation dynamics in the 3pπD(1)Πu (±)υ=3 and 4pσB(″) (1)Σu (+)υ=1 states of H2 revealed by product branching ratios and fragment angular distributions. J Chem Phys 2016; 144:154305. [PMID: 27389218 DOI: 10.1063/1.4945810] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The predissociation dynamics of H2+XUV→H2 (*)→H(1s)+H(2s,2p) has been studied by measuring the fragment branching ratios between the H(2s) and H(2p) states and the fragment angular distributions using the XUV (extreme ultraviolet) laser pump and UV(ultraviolet) laser probe method. The fragment angular distributions for the predissociation of the 3pπD(1)Πu (+)υ=3 state show parallel transitions, demonstrating that the main components of the dissociating state have (1)Σu (+) symmetry. The measured fragment branching ratios, H(2s)/(H(2s) + H(2p)), for the transitions R(0), R(1), and P(2) in 3pπD(1)Πu (+)υ=3←X(1)Σg (+)υ(″)=0 are in good agreement with one of the previous theoretical predictions. The predissociations of the 3pπD(1)Πu (-)(υ=3) state arising from the Q(1), Q(2), and Q(3) lines have also been observed. The angular distributions and the state distributions of the excited fragments (all found from the H(2p) state) illustrate that the dissociating states for the Q lines have the expected Πu (-) symmetry. The predissociation dynamics of the transition 4pσB(″1)Σu (+)υ=1←X(1)Σg (+)υ(″)=0 was also studied. Their fragment angular distributions show the expected parallel transitions, and most of the fragments are in the H(2s) states. The Beutler-Fano profiles and the associated spectroscopic parameters for the predissociations have also been obtained by measuring the fragment yield of H(2s, 2p) as a function of excitation photon energies.
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Affiliation(s)
- Qingnan Meng
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Yuxiang Mo
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
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Sun W, Dai Z, Wang J, Mo Y. The Renner-Teller effect in HCCCl(+)(X̃(2)Π) studied by zero-kinetic energy photoelectron spectroscopy and ab initio calculations. J Chem Phys 2015; 142:194304. [PMID: 26001458 DOI: 10.1063/1.4919953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The spin-vibronic energy levels of the chloroacetylene cation up to 4000 cm(-1) above the ground state have been measured using the one-photon zero-kinetic energy photoelectron spectroscopic method. The spin-vibronic energy levels have also been calculated using a diabatic model, in which the potential energy surfaces are expressed by expansions of internal coordinates, and the Hamiltonian matrix equation is solved using a variational method with harmonic basis functions. The calculated spin-vibronic energy levels are in good agreement with the experimental data. The Renner-Teller (RT) parameters describing the vibronic coupling for the H-C≡C bending mode (ε4), Cl-C≡C bending mode (ε5), the cross-mode vibronic coupling (ε45) of the two bending vibrations, and their vibrational frequencies (ω4 and ω5) have also been determined using an effective Hamiltonian matrix treatment. In comparison with the spin-orbit interaction, the RT effect in the H-C≡C bending (ε4) mode is strong, while the RT effect in the Cl-C≡C bending mode is weak. There is a strong cross-mode vibronic coupling of the two bending vibrations, which may be due to a vibronic resonance between the two bending vibrations. The spin-orbit energy splitting of the ground state has been determined for the first time and is found to be 209 ± 2 cm(-1).
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Affiliation(s)
- Wei Sun
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Zuyang Dai
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Jia Wang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Yuxiang Mo
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
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Mollet S, Merkt F. The X+ 2Πg, A+ 2Πu, B+ 2Δu, and a+ 4Σu(-) electronic states of Cl2(+) studied by high-resolution photoelectron spectroscopy. J Chem Phys 2013; 139:034302. [PMID: 23883022 DOI: 10.1063/1.4812376] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Partially rotationally resolved pulsed-field-ionization zero-kinetic-energy photoelectron spectra of the three isotopomers ((35)Cl2, (35)Cl(37)Cl, and (37)Cl2) of Cl2 have been recorded in the wavenumber ranges 92,500-96,500 cm(-1), corresponding to transitions to the low vibrational levels of the X(+) (2)Πg (Ω = 3∕2, 1∕2) ground state of Cl2 (+), and 106,750-115,500 cm(-1), where the a(+) (4)Σu (-)←X(1)Σg (+), A(+) (2)Πu←X(1)Σg (+), and B(+) (2)Δu←X(1)Σg (+) band systems overlap with transitions to high vibrational levels (v(+) > 25) of the X(+) state. The observation of Franck-Condon-forbidden transitions to vibrational levels of the X(+) state of the cation with v(+) ≥ 25 is rationalized by a mechanism involving vertical excitation of predissociative Rydberg states of mixed singlet-triplet character with an A(+) ion core which are coupled to Rydberg states converging to high-v(+) levels of the X(+) state. The same mechanism is proposed to also be responsible for the observation of Cl(+) - Cl(-) ion pairs and quartet states in the photoionization of Cl2. The potential energy function of the X(+) state of Cl2 (+) was determined in a direct fit to the experimental data. Transitions to vibrational levels of the A(+) (2)Πu, 3∕2 and B(+) (2)Δu, 3∕2 states of Cl2 (+) could be identified using the results of a recent analysis of the strong perturbation between the A(+) (2)Πu, 3∕2 and B(+) (2)Δu, 3∕2 states of Cl2 (+) observed in the A(+) - X(+) band system [Gharaibeh et al., J. Chem. Phys. 137, 194317 (2012)], and transitions to several vibrational levels of the upper spin-orbit component ((2)Πu, 1∕2) of the A(+) state were detected in the photoelectron spectrum of Cl2 (+). The a(+) (4)Σu (-)←X(1)Σg (+) photoelectron band system, which is nominally forbidden by single-photon ionization from the ground state was also observed for the first time and its vibrational and spin-orbit structures were analyzed. The (4)Σu (-) state is split into two spin-orbit components with Ω = 1∕2 and Ω = 3∕2, separated by 37.5 cm(-1). The vibrational energy level structure of both components is regular, which indicates that the splitting results from the interaction with one or more distant ungerade Ω = 1∕2 or Ω = 3∕2 electronic states.
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Affiliation(s)
- Sandro Mollet
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
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Gharaibeh MA, Clouthier DJ, Kalemos A, Lefebvre-Brion H, Field RW. A new, definitive analysis of a very old spectrum: The highly perturbed A2Πu–X 2Πg band system of the chlorine cation ( Cl 2+). J Chem Phys 2012. [DOI: 10.1063/1.4765334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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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Multiconfigurational study on the synchronous mechanisms of the ClO self-reaction leading to Cl or Cl2. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1194-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Shao Z, Li H, Zhang S, Li J, Dai Z, Mo Y, Bae YJ, Kim MS. The Jahn-Teller effect in CH 3 Cl +(X̃E2): A combined high-resolution experimental measurement and ab initio theoretical study. J Chem Phys 2012; 136:064308. [DOI: 10.1063/1.3679655] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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12
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Csontos J, Kállay M. Benchmark Theoretical Study on the Dissociation Energy of Chlorine. J Phys Chem A 2011; 115:7765-72. [DOI: 10.1021/jp2020879] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- József Csontos
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budapest P.O. Box 91, H-1521 Hungary
| | - Mihály Kállay
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budapest P.O. Box 91, H-1521 Hungary
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Chen LL, Tian SX, Xu YF, Chu GB, Liu FY, Shan XB, Sheng LS. Ion-Pair Photodissociation of Trichloromonofluoromethane. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/03/261-266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Chen LL, Xu YF, Feng Q, Tian SX, Liu FY, Shan XB, Sheng LS. Vacuum ultraviolet negative photoion spectroscopy of chloroform. J Phys Chem A 2011; 115:4248-54. [PMID: 21456568 DOI: 10.1021/jp2000927] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Negative ions Cl(-), Cl(2)(-), CCl(-), CHCl(-), and CCl(2)(-) are observed in vacuum-ultraviolet ion-pair photodissociations of chloroform (CCl(3)H) using the Hefei synchrotron radiation facility, and their ion production efficiency curves are recorded in the photon energy range of 10.00-21.50 eV. Two similar spectra of the isotope anions (35)Cl(-) and (37)Cl(-) indicate the following: Besides the strong bands corresponding to the electron transitions from valence to Rydberg orbitals converging to the ionic states, some additional peaks can be assigned with the energetically accessible multibody fragmentations; a distinct peak at photon energy 14.55 eV may be due to a cascade process (namely, the Cl(2) neutral fragment at the highly excited state D'2(3)Π(g) may be produced in the photodissociation of CCl(3)H, and then the Cl(-) anions are produced in the pulsed-field induced ion-pair dissociations of Cl(2) (D'2(3)Π(g))); two vibrational excitation progressions, nν(2)(+) and nν(2)(+) + ν(3)(+), and nν(4)(+) and nν(4)(+) + ν(2)(+), are observed around C̃ (2)E and D̃ (2)E ionic states, respectively. The enthalpies of the multibody fragmentations to Cl(2)(-), CCl(-), CHCl(-), and CCl(2)(-) are calculated with the thermochemistry data available in the literature, and these multibody ion-pair dissociation pathways are tentatively assigned in the respective anion production spectra.
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Affiliation(s)
- Liu-Li Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, China
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Multiphoton dissociation and vibrational mediated dissociation of chlorinated methanes, CH4−nCln (n=2, 3, 4) at 355nm. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Hao Y, Zhou C, Mo Y. Ion-Pair Dissociation Dynamics of Cl 2 in the Range 13.26−13.73 eV Studied by Using XUV Laser and the Velocity Map Imaging Method. J Phys Chem A 2009; 113:2294-303. [DOI: 10.1021/jp8097878] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yusong Hao
- Department of Physics and Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084, China
| | - Chang Zhou
- Department of Physics and Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084, China
| | - Yuxiang Mo
- Department of Physics and Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084, China
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Zhou C, Hao Y, Mo Y. Ion-pair dissociation dynamics of Cl2: adiabatic state correlation. J Phys Chem A 2008; 112:8263-72. [PMID: 18702461 DOI: 10.1021/jp804272w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ion-pair dissociation dynamics of Cl2 -->(XUV) Cl(-)((1)S0) + Cl(+)((3P(2,1,0)) in the range 12.41-12.74 eV have been studied employing coherent extreme ultraviolet (XUV) radiation and the velocity map imaging) method. The ion-pair yield spectrum has been measured, and 72 velocity map images of Cl(-)((1)S0) have been recorded for the peaks in the spectrum. From the images, the branching ratios among the three spin-orbit components Cl(+)((3)P2), Cl(+)((3)P1) and Cl(+)((3)P0) and their corresponding anisotropic parameters beta have been determined. The ion-pair dissociation mechanism is explained by predissociation of Rydberg states converging to ion-core Cl2(+)(A(2)Pi(u)). The Cl(-)((1)S0) ion-pair yield spectrum has been assigned based on the symmetric properties of Rydberg states determined in the imaging experiments. The parallel and perpendicular transitions correspond to the excitation to two major Rydberg series, [A(2)Pi(u)]3d pi(g), (1)Sigma(u)(+) and [A(2)Pi(u)]5s sigma(g), (1)Pi(u), respectively. For the production of Cl(+)((3)P0), it is found that all of them are from parallel transitions. But for Cl(+)((3)P1), most of them are from perpendicular transitions. The production of Cl(+)((3)P2) is the major channel in this energy region, and they come from both parallel and perpendicular transitions. It is found that for most of the predissociations the projection of the total electronic angular momentum on the molecular axis (Omega) is conserved. The ion-pair dissociation may be regarded as a probe for the symmetric properties of Rydberg states.
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Affiliation(s)
- Chang Zhou
- Department of Physics and Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing, 100084, China
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Zhou C, Mo Y. Ion-pair dissociation of N2O in the 16.25-16.41 eV: dynamics and electronic structure. J Chem Phys 2008; 129:064312. [PMID: 18715074 DOI: 10.1063/1.2965593] [Citation(s) in RCA: 6] [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 ion-pair dissociation dynamics of N(2)O -->(XUV) N(2)(+)(X (2)Sigma(g)(+), v) + O(-)((2)P(j)) at 16.248, 16.271, 16.389, and 16.411 eV have been studied using the velocity map imaging method and tunable XUV laser. The electronic structures of the ion-pair states have been studied by employing the ab initio quantum chemical calculation. The translational energy distributions and the angular distributions of the photofragments have been measured. The results show that about 40% of available energies are transformed into the translational energies, and the first excited vibrational states are populated most strongly for all four excitation energies. The anisotropy parameters beta are approximately 1. The ab initio calculations at the level of CASSCF6-311++g(3df) show that the equilibrium geometries of the ion-pair states are nonlinear with bond lengths R(N-N) = 1.10 A, R(N-O) = 2.15 A, and bond angle N-N-O = 103 degrees, respectively. The ion-pair states are formed by electron migration from the bonding sigma orbital of N[triple bond]N to the antibonding sigma orbital localized primarily on the O atom. Combining the experimental and theoretical results, it is concluded that the ion-pair dissociation occurs via predissociation of Rydberg states with (1)Sigma(+) symmetry, which converges to the ion-core N(2)O(+)(A (2)Sigma(+)).
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Affiliation(s)
- Chang Zhou
- Department of Physics and Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing, 100084, China
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Hao Y, Zhou C, Mo Y. Ion-pair formation dynamics of F(2) at 18.385 eV studied by velocity map imaging method. J Phys Chem A 2007; 111:10887-90. [PMID: 17929783 DOI: 10.1021/jp074780a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We studied the ion-pair formation dynamics of F2 at 18.385 eV (67.439 nm) using the velocity map imaging method. It was found that there are two dissociation channels corresponding to production of F(+)((1)D(2)) + F(-)((1)S(0)) and F(+)((3)P(j)) + F(-)((1)S(0)). The measured center-of-mass translational energy distribution shows that about 98% of the dissociation occurs via the F(+)((1)D(2)) channel. The measured angular distributions of the photofragments indicate that dissociation for the F(+)((3)P(j)) channel occurs via predissociation of Rydberg states converging to F(2)(+)(A(2)Pi(u)) and dissociation for the F(+)((1)D(2)) channel involves mainly a direct perpendicular transition into the ion-pair state, or X(1)Sigma(g)(+) --> 2(1)Pi(u), which is also supported by the transition dipole moment calculations .
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Affiliation(s)
- Yusong Hao
- Department of Physics, Key Laboratory for Atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084, China
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