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Parsons BF, Rivera MR, Onder MK. NO (A) Rotational State Distributions from Photodissociation of the N 2-NO Complex. J Phys Chem A 2022; 126:5729-5737. [PMID: 35994689 DOI: 10.1021/acs.jpca.2c04265] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have recorded the resonance-enhanced multiphoton ionization spectrum for NO (A) products from photodissociation of the N2-NO complex. We made measurements at excitation energies ranging from 28 to 758 cm-1 above the threshold to produce NO (A) + N2 (X) products, and the resulting spectra reveal the NO (A) rotational states formed during dissociation, allowing us to determine the rotational state distribution. At the lowest available energies, 28 and 50 cm-1 above threshold, we observed contributions from NO (A) rotational states that exceed the available energy and must originate from excitation due to hotbands of the complex. At all higher energies, we did not observe any energetically disallowed NO (A) rotational states, and for all available energies above 259 cm-1 the observed rotational transitions do not extend to the maximum allowed by energy conservation. Furthermore, the observed distributions were typically biased toward low rotational states, in contrast with expectations from vibrational predissociation. From the rotational state distributions, we determined the average fraction of energy partitioned into NO (A) rotation, fNO rot, ave, to be 0.088 at the highest available energy, and this fraction increased as the available energy decreased. By combining the average NO (A) rotational energy along with the average center-of-mass translational energy from our previous work, we determined the average rotational energy for the undetected N2 (X) photoproduct. The results showed that the N2 fragment has a higher average rotational energy relative to the NO fragment. Finally, we found that the NO (A) rotational state distribution was colder than expected for a statistical dissociation.
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Affiliation(s)
- Bradley F Parsons
- Department of Chemistry and Biochemistry, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Marcos R Rivera
- Department of Chemistry and Biochemistry, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Michael K Onder
- Department of Chemistry and Biochemistry, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
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2
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Schwermann C, Linden S, Doltsinis NL, Zacharias H. On-Surface Chemistry Induced by Long-Lived Excitons: (NO) 2 Dissociation on C 60. J Phys Chem Lett 2020; 11:5490-5496. [PMID: 32584044 DOI: 10.1021/acs.jpclett.0c01247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solid-state excitonic excitations play an increasingly important role in optoelectronic and light harvesting processes due to their ubiquitous presence in dipolar two-dimensional materials. Here we show that long-lived solid-state excitons induce chemical reactions in adsorbed molecules and thus convert light into chemical energy. For the model system (NO)2 dimer adsorbed on ordered c(4×4) C60 films, time-of-flight measurements following UV laser excitation reveal a slow and a fast dissociative desorption channel, which are assigned to intersystem crossing and internal conversion, respectively, by time-dependent density functional theory calculations.
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Affiliation(s)
- Christian Schwermann
- Institute of Solid State Theory and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Steffen Linden
- Institute of Physics, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Nikos L Doltsinis
- Institute of Solid State Theory and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Helmut Zacharias
- Institute of Physics, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
- Center for Soft Nanoscience, Westfälische Wilhelms-Universität, Busso-Peus-Straße 10, 48149 Münster, Germany
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3
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Peng P, Schiappacasse C, Zhou N, Addy M, Cheng Y, Zhang Y, Ding K, Wang Y, Chen P, Ruan R. Sustainable Non-Thermal Plasma-Assisted Nitrogen Fixation-Synergistic Catalysis. CHEMSUSCHEM 2019; 12:3702-3712. [PMID: 31168952 DOI: 10.1002/cssc.201901211] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/05/2019] [Indexed: 06/09/2023]
Abstract
In this Minireview, the multiple chemical synergies present in catalytic non-thermal plasma-assisted nitrogen fixation (NTPNF) are uncovered through a critical exploration of the underlying mechanisms, during which the catalyst, plasma, and reactants play different roles. For the gas-phase NTPNF, the synergies consist of different aspects of the catalytic pathways such as electron-impact dissociation; Zeldovich mechanism in the PNO interactions; and Eley-Rideal, Langmuir-Hinshelwood, surface adsorption, and diffusion mechanisms for the plasma-catalyst interactions. The synergies within the gas-liquid NTPNF involve contributions of plasma and UV excitation to the gas-phase reactions and the UV excitation of molecules at the liquid-surface interface, which improves synthesis of aqueous nitrate, nitrite, and ammonium products. Based on the various synergistic mechanisms during NTPNF, future potential applications are proposed for how NTPNF could benefit the sustainable nitrogen fixation industry.
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Affiliation(s)
- Peng Peng
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
| | - Charles Schiappacasse
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
| | - Nan Zhou
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
| | - Min Addy
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
| | - Yanling Cheng
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
| | - Yaning Zhang
- Harbin Institute of Technology, Harbin, Heilongjiang, 150001, P.R. China
| | - Kuan Ding
- College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, P.R. China
| | - Yunpu Wang
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
- MOE Biomass Engineering Research Center, Nanchang University, Jiangxi, 330047, P.R. China
| | - Paul Chen
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
| | - Roger Ruan
- Center for Biorefining, and Department of Bioproducts and Biosystems Engineering, University of Minnesota Twin Cities, 1390 Eckles Ave., St. Paul, Minnesota, 55108, USA
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4
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Holmes-Ross HL, Valenti RJ, Yu HG, Hall GE, Lawrance WD. Rotational and angular distributions of NO products from NO-Rg (Rg = He, Ne, Ar) complex photodissociation. J Chem Phys 2016; 144:044309. [PMID: 26827219 DOI: 10.1063/1.4940690] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the results of an investigation into the rotational and angular distributions of the NO à state fragment following photodissociation of the NO-He, NO-Ne, and NO-Ar van der Waals complexes excited via the à ← X̃ transition. For each complex, the dissociation is probed for several values of Ea, the available energy above the dissociation threshold. For NO-He, the Ea values probed were 59, 172, and 273 cm(-1); for NO-Ne they were 50 and 166 cm(-1); and for NO-Ar they were 44, 94, 194, and 423 cm(-1). The NO à state rotational distributions arising from NO-He are cold, with most products in low angular momentum states. NO-Ne leads to broader NO rotational distributions but they do not extend to the maximum possible given the energy available. In the case of NO-Ar, the distributions extend to the maximum allowed at that energy and show the unusual shapes associated with the rotational rainbow effect reported in previous studies. This is the only complex for which a rotational rainbow effect is observed at the chosen Ea values. Product angular distributions have also been measured for the NO à photodissociation product for the three complexes. NO-He produces nearly isotropic fragments, but the anisotropy parameter, β, for NO-Ne and NO-Ar photofragments shows a surprising change in sign from negative to positive as Ea increases within the unstructured excitation profile. Franck-Condon selection of a broader distribution of geometries including more linear geometries at lower excitation energies and more T-shaped geometries at higher energies can account for the changing recoil anisotropy. Two-dimensional wavepacket calculations are reported to model the rotational state distributions and the bound-continuum absorption spectra.
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Affiliation(s)
- Heather L Holmes-Ross
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Rebecca J Valenti
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Hua-Gen Yu
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - Gregory E Hall
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - Warren D Lawrance
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
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5
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Epshtein M, Portnov A, Kupfer R, Rosenwaks S, Bar I. Enhanced sensitivity in H photofragment detection by two-color reduced-Doppler ion imaging. J Chem Phys 2013; 139:184201. [PMID: 24320267 DOI: 10.1063/1.4828891] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Two-color reduced-Doppler (TCRD) and one-color velocity map imaging (VMI) were used for probing H atom photofragments resulting from the ~243.1 nm photodissociation of pyrrole. The velocity components of the H photofragments were probed by employing two counterpropagating beams at close and fixed wavelengths of 243.15 and 243.12 nm in TCRD and a single beam at ~243.1 nm, scanned across the Doppler profile in VMI. The TCRD imaging enabled probing of the entire velocity distribution in a single pulse, resulting in enhanced ionization efficiency, as well as improved sensitivity and signal-to-noise ratio. These advantages were utilized for studying the pyrrole photodissociation at ~243.1 and 225 nm, where the latter wavelength provided only a slight increase in the H yield over the self-signal from the probe beams. The TCRD imaging enabled obtaining high quality H(+) images, even for the low H photofragment yields formed in the 225 nm photolysis process, and allowed determining the velocity distributions and anisotropy parameters and getting insight into pyrrole photodissociation.
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Affiliation(s)
- Michael Epshtein
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Melko JJ, Ard SG, Fournier JA, Shuman NS, Troe J, Viggiano AA. Comment on “Role of (NO)2 Dimer in Reactions of Fe+ with NO and NO2 Studied by ICP-SIFT Mass Spectrometry”. J Phys Chem A 2013; 117:9108-10. [DOI: 10.1021/jp404945p] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua J. Melko
- Air Force Research
Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117-5776, United States
| | - Shaun G. Ard
- Air Force Research
Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117-5776, United States
| | - Joseph A. Fournier
- Sterling Chemistry
Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Nicholas S. Shuman
- Air Force Research
Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117-5776, United States
| | - Jürgen Troe
- Institut
für
Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany, and Max-Planck-Institut für Biophysikalische Chemie, D-37077 Göttingen, Germany
| | - Albert A. Viggiano
- Air Force Research
Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117-5776, United States
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7
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Rocher-Casterline BE, Mollner AK, Ch’ng LC, Reisler H. Imaging H2O Photofragments in the Predissociation of the HCl−H2O Hydrogen-Bonded Dimer. J Phys Chem A 2011; 115:6903-9. [DOI: 10.1021/jp112024s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Blithe E. Rocher-Casterline
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Andrew K. Mollner
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Lee C. Ch’ng
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Hanna Reisler
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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8
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Holmes-Ross HL, Lawrance WD. The dissociation of NO-Ar(A) from around threshold to 200 cm(-1) above threshold. J Chem Phys 2010; 133:014304. [PMID: 20614966 DOI: 10.1063/1.3458911] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report an investigation of the dissociation of A state NO-Ar at energies from 23 cm(-1) below the dissociation energy to 200 cm(-1) above. The NO product rotational distributions show population in states that are not accessible with the energy available for excitation from the NO ground state. This effect is observed at photon energies from below the dissociation energy up to approximately 100 cm(-1) above it. Translational energy distributions, extracted from velocity map images of individual rotational levels of the NO product, reveal contributions from excitation of high energy NO-Ar X states at all the excess energies probed, although this diminishes with increasing photon energy and is quite small at 200 cm(-1), the highest energy studied. These translational energy distributions show that there are contributions arising from population in vibrational levels up to the X state dissociation energy. We propose that the reason such sparsely populated levels contribute to the observed dissociation is a considerable increase in the transition moment, via the Franck-Condon factor associated with these highly excited states, which arises because of the quite different geometries in the NO-Ar X and A states. This effect is likely to arise in other systems with similarly large geometry changes.
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Affiliation(s)
- Heather L Holmes-Ross
- School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, South Australia 5001, Australia
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9
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Casterline BE, Mollner AK, Ch’ng LC, Reisler H. Imaging the State-Specific Vibrational Predissociation of the Hydrogen Chloride−Water Hydrogen-Bonded Dimer. J Phys Chem A 2010; 114:9774-81. [DOI: 10.1021/jp102532m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Blithe E. Casterline
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Andrew K. Mollner
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Lee C. Ch’ng
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Hanna Reisler
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
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10
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Marouani S, Bahri M, Batis H, Hochlaf M. Reactivity of the NO dimer: on the role of the triplet electronic states. J Phys Chem A 2010; 114:3025-30. [PMID: 19743862 DOI: 10.1021/jp905994u] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We performed ab initio calculations to investigate the lowest triplet and singlet electronic states of the NO dimer and their mutual spin-orbit couplings. The electronic structure calculations are done using multiconfigurational approaches and a large diffuse basis set. A high density of electronic states is found favoring their mutual interactions by vibronic and spin-orbit couplings. We used our potential curves and spin-orbit couplings to discuss the mechanisms for the IR dissociation and the UV photodissociation of the NO dimer and the electronic de-excitation of NO (A(2)Sigma(+)) after collision with NO (X(2)Pi). For these reactions, multistep pathways, which involve the long-range and the molecular regions of the potential energy surfaces of the triplet and singlet electronic states of N(2)O(2), are suggested. A qualitative agreement between our findings and previous experimental assumptions is found.
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Affiliation(s)
- S Marouani
- Laboratoire de Spectroscopie Atomique, Moléculaire et Application, Faculté des sciences de Tunis, Département de Physique, Université Tunis El Manar, 1060 Tunis, Tunisia
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11
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Beckers H, Zeng X, Willner H. Intermediates Involved in the Oxidation of Nitrogen Monoxide: Photochemistry of thecis-N2O2⋅O2complex and ofsym-N2O4in Solid Ne Matrices. Chemistry 2010; 16:1506-20. [DOI: 10.1002/chem.200902406] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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12
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Chichinin AI, Gericke KH, Kauczok S, Maul C. Imaging chemical reactions – 3D velocity mapping. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903235045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Abstract
Photofragment spectroscopy is combined with imaging techniques and time-resolved measurements of photoions and photoelectrons to explore the predissociation dynamics of weakly bound molecules. Recent experimental advances include measurements of pair-correlated distributions, in which energy disposal in one cofragment is correlated with a state-selected level of the other fragment, and femtosecond pump-probe experiments, in some cases with coincidence detection. An application in which coincident measurements are carried out in the molecular frame is also described. To illustrate these state-selective and time-resolved techniques, we review two recent applications: (a) the photoinitiated dissociation of the covalently bound NO dimer on the ground and excited electronic states and the role of state couplings and (b) the state-selected vibrational predissociation of hydrogen-bonded acetylene dimers with HCl (acid) and ammonia (base) and the importance of angular momentum constraints. We highlight the crucial role of theoretical models in interpreting results.
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Affiliation(s)
- Hanna Reisler
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
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14
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Kim KH, Watanabe K, Menzel D, Freund HJ. Photoinduced Abstraction Reactions within NO Dimers on Ag(111). J Am Chem Soc 2009; 131:1660-1. [DOI: 10.1021/ja808615m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ki Hyun Kim
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany, and Physik-Department E20, Technische Universität München, 85748 Garching, Germany
| | - Kazuo Watanabe
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany, and Physik-Department E20, Technische Universität München, 85748 Garching, Germany
| | - Dietrich Menzel
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany, and Physik-Department E20, Technische Universität München, 85748 Garching, Germany
| | - Hans-Joachim Freund
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany, and Physik-Department E20, Technische Universität München, 85748 Garching, Germany
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15
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Shi H, East ALL. Improved results for the excited states of nitric oxide, including the B/C avoided crossing. J Chem Phys 2007; 125:104311. [PMID: 16999530 DOI: 10.1063/1.2336214] [Citation(s) in RCA: 21] [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 potential energy surfaces of ten electronic states of nitric oxide (NO) have been reexamined computationally, with state energies calculated using ab initio multireference methods. Our wave function expansions of 10x10(6) configurations improve upon the results of de Vivie and Peyerimhoff [J. Chem. Phys. 89, 3028 (1988)], who obtained excellent results from expansions of 16 000 configurations in 1988. We present results for the adiabatic properties r(e), B(e), T(e), and omega(e), demonstrating standard errors of 0.012 A, 0.026 cm(-1), 620 cm(-1), and 41 cm(-1), respectively. Vertical excitation energies and oscillator strengths are also presented, as are potential energy surface curves, with special attention to the B/C avoided crossing. The technical issue of state-averaging effects is also discussed.
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Affiliation(s)
- Huancong Shi
- Department of Chemistry and Biochemistry, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
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Levchenko SV, Reisler H, Krylov AI, Gessner O, Stolow A, Shi H, East ALL. Photodissociation dynamics of the NO dimer. I. Theoretical overview of the ultraviolet singlet excited states. J Chem Phys 2007; 125:084301. [PMID: 16965006 DOI: 10.1063/1.2222355] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular orbital theory and calculations are used to describe the ultraviolet singlet excited states of NO dimer. Qualitatively, we derive and catalog the dimer states by correlating them with monomer states, and provide illustrative complete active space self-consistent field calculations. Quantitatively, we provide computational estimates of vertical transition energies and absorption intensities with multireference configuration interaction and equations-of-motion coupled-cluster methods, and examine an important avoided crossing between a Rydberg and a valence state along the intermonomer and intramonomer stretching coordinates. The calculations are challenging, due to the high density of electronic states of various types (valence and Rydberg, excimer and charge transfer) in the 6-8 eV region, and the multiconfigurational nature of the ground state. We have identified a bright charge-transfer (charge-resonance) state as responsible for the broadband seen in UV absorption experiments. We also use our results to facilitate the interpretation of UV photodissociation experiments, including the time-resolved 6 eV photodissociation experiments to be presented in the next two papers of this series.
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Affiliation(s)
- Sergey V Levchenko
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA
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17
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Gessner O, Lee AMD, Shaffer JP, Reisler H, Levchenko SV, Krylov AI, Underwood JG, Shi H, East ALL, Wardlaw DM, Chrysostom ETH, Hayden CC, Stolow A. Femtosecond Multidimensional Imaging of a Molecular Dissociation. Science 2006; 311:219-22. [PMID: 16357226 DOI: 10.1126/science.1120779] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The coupled electronic and vibrational motions governing chemical processes are best viewed from the molecule's point of view-the molecular frame. Measurements made in the laboratory frame often conceal information because of the random orientations the molecule can take. We used a combination of time-resolved photoelectron spectroscopy, multidimensional coincidence imaging spectroscopy, and ab initio computation to trace a complete reactant-to-product pathway-the photodissociation of the nitric oxide dimer-from the molecule's point of view, on the femtosecond time scale. This method revealed an elusive photochemical process involving intermediate electronic configurations.
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Affiliation(s)
- O Gessner
- Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
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18
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Li G, Parr J, Fedorov I, Reisler H. Imaging study of vibrational predissociation of the HCl–acetylene dimer: pair-correlated distributions. Phys Chem Chem Phys 2006; 8:2915-24. [PMID: 16880903 DOI: 10.1039/b603107b] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The state-to-state predissociation dynamics of the HCl-acetylene dimer were studied following excitation in the asymmetric C-H (asym-CH) stretch and the HCl stretch. Velocity map imaging (VMI) and resonance enhanced multiphoton ionization (REMPI) were used to determine pair-correlated product energy distributions. Different vibrational predissociation mechanisms were observed for the two excited vibrational levels. Following excitation in the of the asym-CH stretch fundamental, HCl fragments in upsilon = 0 and j = 4-7 were observed and no HCl in upsilon = 1 was detected. The fragments' center-of-mass (c.m.) translational energy distributions were derived from images of HCl (j = 4-7), and were converted to rotational state distributions of the acetylene co-fragment by assuming that acetylene is generated with one quantum of C-C stretch (nu(2)) excitation. The acetylene pair-correlated rotational state distributions agree with the predictions of the statistical phase space theory, restricted to acetylene fragments in 1nu(2). It is concluded that the predissociation mechanism is dominated by the initial coupling of the asym-CH vibration to a combination of C-C stretch and bending modes in the acetylene moiety. Vibrational energy redistribution (IVR) between acetylene bending and the intermolecular dimer modes leads to predissociation that preserves the C-C stretch excitation in the acetylene product while distributing the rest of the available energy statistically. The predissociation mechanism following excitation in the Q band of the dimer's HCl stretch fundamental was quite different. HCl (upsilon = 0) rotational states up to j = 8 were observed. The rovibrational state distributions in the acetylene co-fragment derived from HCl (j = 6-8) images were non-statistical with one or two quanta in acetylene bending vibrational excitation. From the observation that all the HCl(j) translational energy distributions were similar, it is proposed that there exists a constraint on conversion of linear to angular momentum during predissociation. A dimer dissociation energy of D(0) = 700 +/- 10 cm(-1) was derived.
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Affiliation(s)
- Guosheng Li
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA
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19
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Ashfold MNR, Nahler NH, Orr-Ewing AJ, Vieuxmaire OPJ, Toomes RL, Kitsopoulos TN, Garcia IA, Chestakov DA, Wu SM, Parker DH. Imaging the dynamics of gas phase reactions. Phys Chem Chem Phys 2006; 8:26-53. [PMID: 16482242 DOI: 10.1039/b509304j] [Citation(s) in RCA: 240] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied--most notably in studies of molecular photodissociation and of bimolecular reaction dynamics.
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Potter AB, Wei J, Reisler H. Photoinitiated Predissociation of the NO Dimer in the Region of the Second and Third NO Stretch Overtones. J Phys Chem B 2005; 109:8407-14. [PMID: 16851987 DOI: 10.1021/jp046226w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photofragment yield spectra and NO(X(2)Pi(1/2,3/2); v = 1, 2, 3) product vibrational, rotational, and spin-orbit state distributions were measured following NO dimer excitation in the 4000-7400 cm(-1) region in a molecular beam. Photofragment yield spectra were obtained by monitoring NO(X(2)Pi; v = 1, 2, 3) dissociation products via resonance-enhanced multiphoton ionization. New bands that include the symmetric nu(1) and asymmetric nu(5) NO stretch modes were observed and assigned as 3nu(5), 2nu(1) + nu(5), nu(1) + 3nu(5), and 3nu(1) + nu(5). Dissociation occurs primarily via Deltav = -1 processes with vibrational energy confined preferentially to one of the two NO fragments. The vibrationally excited fragments are born with less rotational energy than predicted statistically, and fragments formed via Deltav = -2 processes have a higher rotational temperature than those produced via Deltav = -1 processes. The rotational excitation likely derives from the transformation of low-lying bending and torsional vibrational levels in the dimer into product rotational states. The NO spin-orbit state distribution reveals a slight preference for the ground (2)Pi(1/2) state, and in analogy with previous results, it is suggested that the predominant channel is X(2)Pi(1/2) + X(2)Pi(3/2). It is suggested that the long-range potential in the N-N coordinate is the locus of nonadiabatic transitions to electronic states correlating with excited product spin-orbit states. No evidence of direct excitation to electronic states whose vertical energies lie in the investigated energy region is obtained.
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Affiliation(s)
- A B Potter
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
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Nahler NH, Vieuxmaire OPJ, Jones JR, Ashfold MNR, Eppink ATJB, Coriou AM, Parker DH. High-Resolution Ion-Imaging Studies of the Photodissociation of the BrCl+ Cation. J Phys Chem A 2004. [DOI: 10.1021/jp049238q] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Dribinski V, Potter A, Fedorov I, Reisler H. Photoexcitation of the NO dimer below the threshold of the NO(A2Σ+)+NO(X2Π) channel: a photoion and photoelectron imaging study. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2003.12.092] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gessner O, Chrysostom ETH, Lee AMD, Wardlaw DM, Ho ML, Lee SJ, Cheng BM, Zgierski MZ, Chen IC, Shaffer JP, Hayden CC, Stolow A. Non-adiabatic intramolecular and photodissociation dynamics studied by femtosecond time-resolved photoelectron and coincidence imaging spectroscopy. Faraday Discuss 2004; 127:193-212. [PMID: 15471347 DOI: 10.1039/b316742a] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Time-resolved photoelectron spectroscopy (TRPES) is emerging as a useful tool for the study of non-adiabatic dynamics in isolated polyatomic molecules and clusters due to its sensitivity to both electronic and vibrational dynamics. A powerful extension of TRPES, coincidence imaging spectroscopy (CIS), based upon femtosecond time-resolved 3D momentum vector imaging of both photoions and photoelectrons in coincidence, is a new technique for the study of complex dissociative processes. Here we show how these spectroscopies can be used to study both non-adiabatic intramolecular and photodissociation dynamics in polyatomic molecules. Intramolecular dynamics in the alpha, beta-enones acrolein, crotonaldehyde and methyl vinyl ketone are studied using both TRPES and laser-induced fluorescence of HCO(X) product yields. The location of the methyl group is seen to have very dramatic effects on the relative electronic relaxation rates and the HCO(X) yield. Applying both TRPES and CIS to the 200 nm and 209 nm photodissociation of the nitric oxide dimer, (NO)2, we observe the fs time-scale evolution of the excited parent neutral via its photoelectron spectrum and the emergence of the NO(A) photofragment including its energy and angular distributions.
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Affiliation(s)
- O Gessner
- Steacie Institute for Molecular Sciences, National Research Council, Ottawa ON, Canada
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Tsubouchi M, Suzuki T. Excitation energy dependence in the electronic dephasing time of the NO dimer. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.10.078] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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