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Augenbraun BL, Burchesky S, Winnicki A, Doyle JM. High-Resolution Laser Spectroscopy of a Functionalized Aromatic Molecule. J Phys Chem Lett 2022; 13:10771-10777. [PMID: 36374523 DOI: 10.1021/acs.jpclett.2c03041] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We present a high-resolution laser spectroscopic study of the Ã2B2-X̃2A1 and B̃2B1-X̃2A1 transitions of calcium(I) phenoxide, CaOPh (CaOC6H5). The rotationally resolved band systems are analyzed using an effective Hamiltonian model and are accurately modeled as independent perpendicular (b- or c-type) transitions. The structure of calcium monophenoxide is compared to previously observed Ca-containing radicals, and implications for direct laser cooling are discussed. This work demonstrates that functionalization of aromatic molecules with optical cycling centers can preserve many of the properties needed for laser-based control.
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Affiliation(s)
- Benjamin L Augenbraun
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - Sean Burchesky
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - Andrew Winnicki
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
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2
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Telfah H, Sharma K, Paul AC, Riyadh SMS, Miller TA, Liu J. A combined experimental and computational study on the transition of the calcium isopropoxide radical as a candidate for direct laser cooling. Phys Chem Chem Phys 2022; 24:8749-8762. [PMID: 35352070 DOI: 10.1039/d1cp04107j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibronically resolved laser-induced fluorescence/dispersed fluorescence (LIF/DF) and cavity ring-down (CRD) spectra of the electronic transition of the calcium isopropoxide [CaOCH(CH3)2] radical have been obtained under jet-cooled conditions. An essentially constant energy separation of 68 cm-1 has been observed for the vibrational ground levels and all fundamental vibrational levels accessed in the LIF measurement. To simulate the experimental spectra and assign the recorded vibronic bands, Franck-Condon (FC) factors and vibrational branching ratios (VBRs) are predicted from vibrational modes and their frequencies calculated using the complete-active-space self-consistent field (CASSCF) and equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) methods. Combined with the calculated electronic transition energy, the computational results, especially those from the EOM-CCSD calculations, reproduced the experimental spectra with considerable accuracy. The experimental and computational results suggest that the FC matrix for the studied electronic transition is largely diagonal, but transitions from the vibrationless levels of the à state to the X̃-state levels of the CCC bending (ν14 and ν15), CaO stretch (ν13), and CaOC asymmetric stretch (ν9 and ν11) modes also have considerable intensities. Transitions to low-frequency in-plane [ν17(a')] and out-of-plane [ν30(a'')] CaOC bending modes were observed in the experimental LIF/DF spectra, the latter being FC-forbidden but induced by the pseudo-Jahn-Teller (pJT) effect. Both bending modes are coupled to the CaOC asymmetric stretch mode via the Duschinsky rotation, as demonstrated in the DF spectra obtained by pumping non-origin vibronic transitions. The pJT interaction also induces transitions to the ground-state vibrational level of the ν10(a') mode, which has the CaOC bending character. Our combined experimental and computational results provide critical information for future direct laser cooling of the target molecule and other alkaline earth monoalkoxide radicals.
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Affiliation(s)
- Hamzeh Telfah
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA.
| | - Ketan Sharma
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Anam C Paul
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA.
| | - S M Shah Riyadh
- Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, USA
| | - Terry A Miller
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Jinjun Liu
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA. .,Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, USA
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3
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Hadizadeh MH, Pan Z, Azamat J. Investigation of OH radical in the water nanodroplet during vapor freezing process: An ab initio molecular dynamics study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Stein T, Jose J. Molecular Formation upon Ionization of van der Waals Clusters and Implication to Astrochemistry. Isr J Chem 2020. [DOI: 10.1002/ijch.201900127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Tamar Stein
- Fritz Haber Research Center for Molecular Dynamics The Hebrew University of Jerusalem Jerusalem 9190401 Israel
| | - Jeeno Jose
- Fritz Haber Research Center for Molecular Dynamics The Hebrew University of Jerusalem Jerusalem 9190401 Israel
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5
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Blackshaw KJ, Quartey NK, Korb RT, Hood DJ, Hettwer CD, Kidwell NM. Imaging the nonreactive collisional quenching dynamics of NO (A 2Σ +) radicals with O 2 (X 3Σ g -). J Chem Phys 2019; 151:104304. [PMID: 31521090 DOI: 10.1063/1.5109112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nitric oxide (NO) radicals are ubiquitous chemical intermediates present in the atmosphere and in combustion processes, where laser-induced fluorescence is extensively used on the NO (A2Σ+ ← X2Π) band to report on fuel-burning properties. However, accurate fluorescence quantum yields and NO concentration measurements are impeded by electronic quenching of NO (A2Σ+) to NO (X2Π) with colliding atomic and molecular species. To improve predictive combustion models and develop a molecular-level understanding of NO (A2Σ+) quenching, we report the velocity map ion images and product state distributions of NO (X2Π, v″ = 0, J″, Fn, Λ) following nonreactive collisional quenching of NO (A2Σ+) with molecular oxygen, O2 (X3Σg -). A novel dual-flow pulse valve nozzle is constructed and implemented to carry out the NO (A2Σ+) electronic quenching studies and to limit NO2 formation. The isotropic ion images reveal that the NO-O2 system evolves through a long-lived NO3 collision complex prior to formation of products. Furthermore, the corresponding total kinetic energy release distributions support that O2 collision coproducts are formed primarily in the c1Σu - electronic state with NO (X2Π, v″ = 0, J″, Fn, Λ). The product state distributions also indicate that NO (X2Π) is generated with a propensity to occupy the Π(A″) Λ-doublet state, which is consistent with the NO π* orbital aligned perpendicular to nuclear rotation. The deviations between experimental results and statistical phase space theory simulations illustrate the key role that the conical intersection plays in the quenching dynamics to funnel population to product rovibronic levels.
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Affiliation(s)
- K Jacob Blackshaw
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Naa-Kwarley Quartey
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Robert T Korb
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - David J Hood
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Christian D Hettwer
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Nathanael M Kidwell
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
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6
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Zhu Y, Lu Y, Song H. Thermal rate coefficients and kinetic isotope effects of the reaction HO + H2O → H2O + OH. Theor Chem Acc 2019. [DOI: 10.1007/s00214-019-2495-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Zhu Y, Ping L, Bai M, Liu Y, Song H, Li J, Yang M. Tracking the energy flow in the hydrogen exchange reaction OH + H 2O → H 2O + OH. Phys Chem Chem Phys 2018; 20:12543-12556. [PMID: 29693667 DOI: 10.1039/c8cp00938d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The prototypical hydrogen exchange reaction OH + H2O → H2O + OH has attracted considerable interest due to its importance in a wide range of chemically active environments. In this work, an accurate global potential energy surface (PES) for the ground electronic state was developed based on ∼44 000 ab initio points at the level of UCCSD(T)-F12a/aug-cc-pVTZ. The PES was fitted using the fundamental invariant-neural network method with a root mean squared error of 4.37 meV. The mode specific dynamics was then studied by the quasi-classical trajectory method on the PES. Furthermore, the normal mode analysis approach was employed to calculate the final vibrational state distribution of the product H2O, in which a new scheme to acquire the Cartesian coordinates and momenta of each atom in the product molecule from the trajectories was proposed. It was found that, on one hand, excitation of either the symmetric stretching mode or the asymmetric stretching mode of the reactant H2O promotes the reaction more than the translational energy, which can be rationalized by the sudden vector projection model. On the other hand, the relatively higher efficacy of exciting the symmetric stretching mode than that of the asymmetric stretching mode is caused by the prevalence of the indirect mechanism at low collision energies and the stripping mechanism at high collision energies. In addition, the initial collision energy turns ineffectively into the vibrational energy of the products H2O and OH while a fraction of the energy transforms into the rotational energy of the product H2O. Fundamental excitation of the stretching modes of H2O results in the product H2O having the highest population in the fundamental state of the asymmetric stretching mode, followed by the ground state and the fundamental state of the symmetric stretching mode.
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Affiliation(s)
- Yongfa Zhu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
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8
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Liu J. Rotational and fine structure of open-shell molecules in nearly degenerate electronic states. J Chem Phys 2018; 148:124112. [DOI: 10.1063/1.5021946] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jinjun Liu
- Department of Chemistry, University of Louisville, 2320 S. Brook St., Louisville, Kentucky 40292, USA
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9
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Bai M, Lu D, Li J. Quasi-classical trajectory studies on the full-dimensional accurate potential energy surface for the OH + H2O = H2O + OH reaction. Phys Chem Chem Phys 2017; 19:17718-17725. [DOI: 10.1039/c7cp02656k] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first accurate PES for the OH + H2O reaction is developed by using the permutation invariant polynomial-neural network method to fit ∼48 000 CCSD(T)-F12a/AVTZ calculated points.
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Affiliation(s)
- Mengna Bai
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 401331
- China
| | - Dandan Lu
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 401331
- China
| | - Jun Li
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 401331
- China
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10
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Advanced Spatial-Division Multiplexed Measurement Systems Propositions-From Telecommunication to Sensing Applications: A Review. SENSORS 2016; 16:s16091387. [PMID: 27589754 PMCID: PMC5038665 DOI: 10.3390/s16091387] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 11/16/2022]
Abstract
The concepts of spatial-division multiplexing (SDM) technology were first proposed in the telecommunications industry as an indispensable solution to reduce the cost-per-bit of optical fiber transmission. Recently, such spatial channels and modes have been applied in optical sensing applications where the returned echo is analyzed for the collection of essential environmental information. The key advantages of implementing SDM techniques in optical measurement systems include the multi-parameter discriminative capability and accuracy improvement. In this paper, to help readers without a telecommunication background better understand how the SDM-based sensing systems can be incorporated, the crucial components of SDM techniques, such as laser beam shaping, mode generation and conversion, multimode or multicore elements using special fibers and multiplexers are introduced, along with the recent developments in SDM amplifiers, opto-electronic sources and detection units of sensing systems. The examples of SDM-based sensing systems not only include Brillouin optical time-domain reflectometry or Brillouin optical time-domain analysis (BOTDR/BOTDA) using few-mode fibers (FMF) and the multicore fiber (MCF) based integrated fiber Bragg grating (FBG) sensors, but also involve the widely used components with their whole information used in the full multimode constructions, such as the whispering gallery modes for fiber profiling and chemical species measurements, the screw/twisted modes for examining water quality, as well as the optical beam shaping to improve cantilever deflection measurements. Besides, the various applications of SDM sensors, the cost efficiency issue, as well as how these complex mode multiplexing techniques might improve the standard fiber-optic sensor approaches using single-mode fibers (SMF) and photonic crystal fibers (PCF) have also been summarized. Finally, we conclude with a prospective outlook for the opportunities and challenges of SDM technologies in optical sensing industry.
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11
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Hoehn RD, Yeole SD, Kais S, Francisco JS. Analytic ab initio-based molecular interaction potential for the BrO⋅H2O complex. J Chem Phys 2016; 144:204121. [PMID: 27250293 DOI: 10.1063/1.4950956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Radical halogen oxide species play important roles within atmospheric processes, specifically those responsible for the removal of O3. To facilitate future investigations on this family of compounds, RCCSD(T)/aug-cc-pVQZ-level electronic structure calculations were employed to generate individual-molecule optimized geometries, as well as to determine the global minimum energy structure for the BrO⋅H2O complex. This information facilitated the generation of several one-dimensional potential energy surface (PES) scans for the BrO⋅H2O complex. Scans were performed for both the ground state and the first excited state; this inclusion is due to a low-lying first electronic excited-state energy. These rigid-geometry PES scans were used both to generate a novel analytic interaction potential by modifying the existing Thole-type model used for water and to the fitted potential function. This interaction potential features anisotropic atomic polarizabilities facilitating appropriate modeling of the physics regarding the unpaired electron residing within the p-orbitals of the oxygen atom of the bromine oxide radical. The intention of this work is to facilitate future molecular dynamics simulations involving the interaction between the BrO radical and water clusters as a first step in devising possible novel chemistries taking place at the water interface of clouds within the atmosphere.
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Affiliation(s)
- Ross D Hoehn
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Sachin D Yeole
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Sabre Kais
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Joseph S Francisco
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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12
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Hernandez FJ, Brice JT, Leavitt CM, Liang T, Raston PL, Pino GA, Douberly GE. Mid-infrared signatures of hydroxyl containing water clusters: Infrared laser Stark spectroscopy of OH–H2O and OH(D2O)n (n = 1-3). J Chem Phys 2015; 143:164304. [DOI: 10.1063/1.4933432] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Federico J. Hernandez
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
- INFIQC, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón, X5000HUA Córdoba, Argentina
| | - Joseph T. Brice
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | | | - Tao Liang
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Paul L. Raston
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, USA
| | - Gustavo A. Pino
- INFIQC, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón, X5000HUA Córdoba, Argentina
| | - Gary E. Douberly
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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13
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Hernandez FJ, Brice JT, Leavitt CM, Pino GA, Douberly GE. Infrared Spectroscopy of OH··CH3OH: Hydrogen-Bonded Intermediate Along the Hydrogen Abstraction Reaction Path. J Phys Chem A 2015; 119:8125-32. [DOI: 10.1021/acs.jpca.5b04875] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Federico J. Hernandez
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
- INFIQC,
Dpto. de Fisicoquímica, Facultad de Ciencias Químicas,
Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón. X5000HUA Córdoba, Argentina
| | - Joseph T. Brice
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | | | - Gustavo A. Pino
- INFIQC,
Dpto. de Fisicoquímica, Facultad de Ciencias Químicas,
Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón. X5000HUA Córdoba, Argentina
| | - Gary E. Douberly
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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14
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Do NH, Cooper PD. Formation and Reaction of Oxidants in Water Ice Produced from the Deposition of RF-Discharged Rare Gas and Water Mixtures. J Phys Chem A 2012; 117:153-9. [PMID: 23237388 DOI: 10.1021/jp3090556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nhut H. Do
- Department of Chemistry and Biochemistry, George Mason University, 4400 University Drive, MSN
3E2 Fairfax, Virginia 22030, United States
| | - Paul D. Cooper
- Department of Chemistry and Biochemistry, George Mason University, 4400 University Drive, MSN
3E2 Fairfax, Virginia 22030, United States
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15
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Affiliation(s)
- Veronica Vaida
- Department of Chemistry and Biochemistry, CIRES, University of Colorado, Boulder, Colorado 80309-0215, USA
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16
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Affiliation(s)
- Daniel M. Chipman
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556-5674, United States
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17
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Soloveichik P, O’Donnell BA, Lester MI, Francisco JS, McCoy AB. Infrared Spectrum and Stability of the H2O−HO Complex: Experiment and Theory. J Phys Chem A 2009; 114:1529-38. [DOI: 10.1021/jp907885d] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pesia Soloveichik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Bridget A. O’Donnell
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Marsha I. Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Joseph S. Francisco
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Anne B. McCoy
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
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18
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Garbuio V, Cascella M, Pulci O. Excited state properties of liquid water. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:033101. [PMID: 21817245 DOI: 10.1088/0953-8984/21/3/033101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper, we give an overview of the state of the art in calculations of the electronic band structure and absorption spectra of water. After an introduction to the main theoretical and computational schemes used, we present results for the electronic and optical excitations of water. We focus mainly on liquid water, but spectroscopic properties of ice and vapor phase are also described. The applicability and the accuracy of first-principles methods are discussed, and results are critically presented.
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Affiliation(s)
- Viviana Garbuio
- European Theoretical Spectroscopy Facility (ETSF), CNR-INFM-SMC, Department of Physics University of Rome Tor Vergata, Italy
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19
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Du S, Francisco JS. OH⋅N[sub 2] and SH⋅N[sub 2] radical-molecule van der Waals complex. J Chem Phys 2009; 131:064307. [PMID: 19691388 DOI: 10.1063/1.3204980] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Shiyu Du
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA
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20
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Brauer CS, Sedo G, Dahlke E, Wu S, Grumstrup EM, Leopold KR, Marshall MD, Leung HO, Truhlar DG. Effects of O18 isotopic substitution on the rotational spectra and potential splitting in the OH–OH2 complex: Improved measurements for O16H–O16H2 and O18H–O18H2, new measurements for the mixed isotopic forms, and ab initio calculations of the A2′-A2″ energy separation. J Chem Phys 2008; 129:104304. [DOI: 10.1063/1.2973638] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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21
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Spectroscopic identification and stability of the intermediate in the OH + HONO2 reaction. Proc Natl Acad Sci U S A 2008; 105:12678-83. [PMID: 18678905 DOI: 10.1073/pnas.0800320105] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The reaction of nitric acid with the hydroxyl radical influences the residence time of HONO(2) in the lower atmosphere. Prior studies [Brown SS, Burkholder JB, Talukdar RK, Ravishankara AR (2001) J Phys Chem A 105:1605-1614] have revealed unusual kinetic behavior for this reaction, including a negative temperature dependence, a complex pressure dependence, and an overall reaction rate strongly affected by isotopic substitution. This behavior suggested that the reaction occurs through an intermediate, theoretically predicted to be a hydrogen-bonded OH-HONO(2) complex in a six-membered ring-like configuration. In this study, the intermediate is generated directly by the association of photolytically generated OH radicals with HONO(2) and stabilized in a pulsed supersonic expansion. Infrared action spectroscopy is used to identify the intermediate by the OH radical stretch (nu(1)) and OH stretch of nitric acid (nu(2)) in the OH-HONO(2) complex. Two vibrational features are attributed to OH-HONO(2): a rotationally structured nu(1) band at 3516.8 cm(-1) and an extensively broadened nu(2) feature at 3260 cm(-1), both shifted from their respective monomers. These same transitions are identified for OD-DONO(2). Assignments of the features are based on their vibrational frequencies, analysis of rotational band structure, and comparison with complementary high level ab initio calculations. In addition, the OH (v = 0) product state distributions resulting from nu(1) and nu(2) excitation are used to determine the binding energy of OH-HONO(2), D(0) <or= 5.3 kcal x mol(-1), which is in good accord with ab initio predictions.
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Abstract
Oxidation of isoprene by the hydroxyl radical leads to tropospheric ozone formation. Consequently, a more complete understanding of this reaction could lead to better models of regional air quality, a better understanding of aerosol formation, and a better understanding of reaction kinetics and dynamics. The most common first step in the oxidation of isoprene is the formation of an adduct, with the hydroxyl radical adding to one of four unsaturated carbon atoms in isoprene. In this paper, we discuss how the initial conformations of isoprene, s-trans and s-gauche, influences the pathways to adduct formation. We explore the formation of pre-reactive complexes at low and high temperatures, which are often invoked to explain the negative temperature dependence of this reaction's kinetics. We show that at higher temperatures the free energy surface indicates that a pre-reactive complex is unlikely, while at low temperatures the complex exists on two reaction pathways. The theoretical results show that at low temperatures all eight pathways possess negative reaction barriers, and reaction energies that range from -36.7 to -23.0 kcal x mol(-1). At temperatures in the lower atmosphere, all eight pathways possess positive reaction barriers that range from 3.8 to 6.0 kcal x mol(-1) and reaction energies that range from -28.8 to -14.4 kcal x mol(-1).
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Affiliation(s)
- Marco A. Allodi
- Department of Chemistry, Center for Molecular Design, Hamilton College, 198 College Hill Road, Clinton, NY 13323
| | - Karl N. Kirschner
- Department of Chemistry, Center for Molecular Design, Hamilton College, 198 College Hill Road, Clinton, NY 13323
| | - George C. Shields
- Department of Chemistry, Center for Molecular Design, Hamilton College, 198 College Hill Road, Clinton, NY 13323
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23
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Du S, Francisco JS, Schenter GK, Garrett BC. Many-body decomposition of the binding energies for OH⋅(H2O)2 and OH⋅(H2O)3 complexes. J Chem Phys 2008; 128:084307. [DOI: 10.1063/1.2828522] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ichino T, Fessenden RW. Reactions of Hydrated Electron with Various Radicals: Spin Factor in Diffusion-Controlled Reactions. J Phys Chem A 2007; 111:2527-41. [PMID: 17388346 DOI: 10.1021/jp0684527] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reactions of hydrated electron (eaq-) with various radicals have been studied in pulse radiolysis experiments. These radicals are hydroxyl radical (*OH), sulfite radical anion (*SO3-), carbonate radical anion (CO3*-), carbon dioxide radical anion (*CO2-), azidyl radical (*N3), dibromine radical anion (Br2*-), diiodine radical anion (I2*-), 2-hydroxy-2-propyl radical (*C(CH3)2OH), 2-hydroxy-2-methyl-1-propyl radical ((*CH2)(CH3)2COH), hydroxycyclohexadienyl radical (*C6H6OH), phenoxyl radical (C6H5O*), p-methylphenoxyl radical (p-(H3C)C6H4O*), p-benzosemiquinone radical anion (p-OC6H4O*-), and phenylthiyl radical (C6H5S*). The kinetics of eaq- was followed in the presence of the counter radicals in transient optical absorption measurements. The rate constants of the eaq- reactions with radicals have been determined over a temperature range of 5-75 degrees C from the kinetic analysis of systems of multiple second-order reactions. The observed high rate constants for all the eaq- + radical reactions have been analyzed with the Smoluchowski equation. This analysis suggests that many of the eaq- + radical reactions are diffusion-controlled with a spin factor of 1/4, while other reactions with *OH, *N3, Br2*-, I2*-, and C6H5S* have spin factors significantly larger than 1/4. Spin dynamics for the eaq-/radical pairs is discussed to explain the different spin factors. The reactions with *OH, *N3, Br2*-, and I2*- have also been found to have apparent activation energies less than that for diffusion control, and it is suggested that the spin factors for these reactions decrease with increasing temperature. Such a decrease in spin factor may reflect a changing competition between spin relaxation/conversion and diffusive escape from the radical pairs.
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Affiliation(s)
- Takatoshi Ichino
- Radiation Laboratory and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5674, USA
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Crawford TD, Abrams ML, King RA, Lane JR, Schofield DP, Kjaergaard HG. The lowest A′2 excited state of the water-hydroxyl complex. J Chem Phys 2006; 125:204302. [PMID: 17144695 DOI: 10.1063/1.2388260] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Vertical and adiabatic excitation energies of the lowest (2)A(') excited state in the water-hydroxyl complex have been determined using coupled cluster, multireference configuration interaction, multireference perturbation theory, and density-functional methods. A significant redshift of about 0.4 eV in the vertical excitation energy of the complex compared to that of the hydroxyl radical monomer is found with the coupled cluster calculations validating previous results. Electronic excitation leads to a structure with near-equal sharing of the hydroxyl hydrogen by both oxygen atoms and a concomitantly large redshift of the adiabatic excitation energy of approximately 1 eV relative to the vertical excitation energy. The combination of redshifts ensures that the electronic transition in the complex lies well outside the equivalent excitation in the hydroxyl radical monomer. The complex is approximately five times more strongly bound in the excited state than in the ground state.
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26
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Guo J, Watkins MJ, Müller-Dethlefs K, Dessent CE. Microsolvation of the chlorine oxide anion and chlorine oxide radical: Structures and energetics of the ClO−·(H2O)n and ClO·(H2O)nn=1–4 clusters. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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27
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Du S, Francisco JS, Schenter GK, Iordanov TD, Garrett BC, Dupuis M, Li J. The OH radical-H2O molecular interaction potential. J Chem Phys 2006; 124:224318. [PMID: 16784285 DOI: 10.1063/1.2200701] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The OH radical is one of the most important oxidants in the atmosphere due to its high reactivity. The study of hydrogen-bonded complexes of OH with the water molecules is a topic of significant current interest. In this work, we present the development of a new analytical functional form for the interaction potential between the rigid OH radical and H(2)O molecules. To do this we fit a selected functional form to a set of high level ab initio data. Since there is a low-lying excited state for the H(2)O.OH complex, the impact of the excited state on the chemical behavior of the OH radical can be very important. We perform a potential energy surface scan using the CCSD(T)/aug-cc-pVTZ level of electronic structure theory for both excited and ground states. To model the physics of the unpaired electron in the OH radical, we develop a tensor polarizability generalization of the Thole-type all-atom polarizable rigid potential for the OH radical, which effectively describes the interaction of OH with H(2)O for both ground and excited states. The stationary points of (H(2)O)(n)OH clusters were identified as a benchmark of the potential.
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Affiliation(s)
- Shiyu Du
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA
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Vissers GWM, McCoy AB. Time-Dependent Wave Packet Studies on the Cl + HCl Hydrogen Exchange Reaction. J Phys Chem A 2006; 110:5978-81. [PMID: 16671664 DOI: 10.1021/jp061196d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The initiation of the hydrogen exchange reaction Cl((2)P)+HCl --> ClH+Cl((2)P) by excitation of the HCl molecular stretch to v=2 is studied for total angular momentum quantum number J=(1)/(2) and both even and odd parity. The calculations were performed using a time-dependent propagation from an initial quasi-bound state and employed all three relevant potential energy surfaces and the nonadiabatic couplings between them. Coriolis and spin-orbit coupling were also taken into account. The electronic and HCl rotational distributions of the products in both dissociation channels are analyzed, and the results are interpreted using features of the potential energy surfaces.
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Affiliation(s)
- Gé W M Vissers
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
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