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Schwarting M, Seifert NA, Davis MJ, Blaiszik B, Foster I, Prozument K. Twins in rotational spectroscopy: Does a rotational spectrum uniquely identify a molecule? J Chem Phys 2024; 161:044309. [PMID: 39051838 DOI: 10.1063/5.0212632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/03/2024] [Indexed: 07/27/2024] Open
Abstract
Rotational spectroscopy is the most accurate method for determining structures of molecules in the gas phase. It is often assumed that a rotational spectrum is a unique "fingerprint" of a molecule. The availability of large molecular databases and the development of artificial intelligence methods for spectroscopy make the testing of this assumption timely. In this paper, we pose the determination of molecular structures from rotational spectra as an inverse problem. Within this framework, we adopt a funnel-based approach to search for molecular twins, which are two or more molecules, which have similar rotational spectra but distinctly different molecular structures. We demonstrate that there are twins within standard levels of computational accuracy by generating rotational constants for many molecules from several large molecular databases, indicating that the inverse problem is ill-posed. However, some twins can be distinguished by increasing the accuracy of the theoretical methods or by performing additional experiments.
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Affiliation(s)
- Marcus Schwarting
- Department of Computer Science, University of Chicago, Chicago, Illinois 60637, USA
| | - Nathan A Seifert
- Department of Chemistry and Chemical and Biomedical Engineering, University of New Haven, West Haven, Connecticut 06516, USA
| | - Michael J Davis
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Ben Blaiszik
- Data Science and Learning Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Ian Foster
- Department of Computer Science, University of Chicago, Chicago, Illinois 60637, USA
- Data Science and Learning Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
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2
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Robinson MS, Küpper J. Unraveling the ultrafast dynamics of thermal-energy chemical reactions. Phys Chem Chem Phys 2024; 26:1587-1601. [PMID: 38131437 DOI: 10.1039/d3cp03954d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
In this perspective, we discuss how one can initiate, image, and disentangle the ultrafast elementary steps of thermal-energy chemical dynamics, building upon advances in technology and scientific insight. We propose that combinations of ultrashort mid-infrared laser pulses, controlled molecular species in the gas phase, and forefront imaging techniques allow to unravel the elementary steps of general-chemistry reaction processes in real time. We detail, for prototypical first reaction systems, experimental methods enabling these investigations, how to sufficiently prepare and promote gas-phase samples to thermal-energy reactive states with contemporary ultrashort mid-infrared laser systems, and how to image the initiated ultrafast chemical dynamics. The results of such experiments will clearly further our understanding of general-chemistry reaction dynamics.
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Affiliation(s)
- Matthew S Robinson
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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3
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Dutton SE, Blake GA. High throughput chirped pulse Fourier-transform microwave spectroscopy of ethanol and water clusters. Phys Chem Chem Phys 2022; 24:13831-13838. [PMID: 35616604 DOI: 10.1039/d2cp01055k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we discuss the design and performance of a novel high-throughput instrument for Chirped Pulse Fourier-transform Microwave (CP-FTMW) spectroscopy, and demonstrate its efficacy through the identification of the lowest energy conformers of the ethanol trimer and mixed water : ethanol trimers. Rotational constants for these trimers were calculated from observed lines in the spectra from 10 to 14 GHz, and compared to the results of anharmonic ab initio computations. As predicted, all trimers share a cyclic donor-acceptor hydrogen bonding structure, with the ethanol monomer favoring the gauche conformation in the lowest energy structures. The increased speed of data collection and resulting sensitivity opens a new avenue into rotational studies of higher order clusters.
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Affiliation(s)
- S E Dutton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA.
| | - G A Blake
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA.
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4
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Stroud JR, Plusquellic DF. Difference-frequency chirped-pulse dual-comb generation in the THz region: Temporal magnification of the quantum dynamics of water vapor lines by >60 000. J Chem Phys 2022; 156:044302. [DOI: 10.1063/5.0076506] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Jasper R. Stroud
- Applied Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - David F. Plusquellic
- Applied Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
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5
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Alessandrini S, Melosso M, Jiang N, Bizzocchi L, Dore L, Puzzarini C. Conformational stability of cyclopropanecarboxaldehyde is ruled by vibrational effects. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1955988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Silvia Alessandrini
- Scuola Normale Superiore, Pisa, Italy
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Bologna, Italy
| | - Mattia Melosso
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Bologna, Italy
| | - Ningjing Jiang
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Bologna, Italy
| | - Luca Bizzocchi
- Scuola Normale Superiore, Pisa, Italy
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Bologna, Italy
| | - Luca Dore
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Bologna, Italy
| | - Cristina Puzzarini
- Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Bologna, Italy
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6
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Stroud JR, Simon JB, Wagner GA, Plusquellic DF. Interleaved electro-optic dual comb generation to expand bandwidth and scan rate for molecular spectroscopy and dynamics studies near 1.6 µm. OPTICS EXPRESS 2021; 29:33155-33170. [PMID: 34809133 DOI: 10.1364/oe.434482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/18/2021] [Indexed: 06/13/2023]
Abstract
A chirped-pulse interleaving method is reported for generation of dual optical frequency combs based on electro-optic phase modulators (EOM) in a free-running all-fiber based system. Methods are discussed to easily modify the linear scan rate and comb resolution by more than three orders of magnitude and to significantly increase the spectral bandwidth coverage. The agility of the technique is shown to both capture complex line shapes and to magnify rapid passage effects in spectroscopic and molecular dynamics studies of CO2. These methods are well-suited for applications in the areas of remote sensing of greenhouse gas emissions, molecular reaction dynamics, and sub-Doppler studies across the wide spectral regions accessible to EOMs.
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Fulvio D, Potapov A, He J, Henning T. Astrochemical Pathways to Complex Organic and Prebiotic Molecules: Experimental Perspectives for In Situ Solid-State Studies. Life (Basel) 2021; 11:life11060568. [PMID: 34204233 PMCID: PMC8235774 DOI: 10.3390/life11060568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 02/05/2023] Open
Abstract
A deep understanding of the origin of life requires the physical, chemical, and biological study of prebiotic systems and the comprehension of the mechanisms underlying their evolutionary steps. In this context, great attention is paid to the class of interstellar molecules known as "Complex Organic Molecules" (COMs), considered as possible precursors of prebiotic species. Although COMs have already been detected in different astrophysical environments (such as interstellar clouds, protostars, and protoplanetary disks) and in comets, the physical-chemical mechanisms underlying their formation are not yet fully understood. In this framework, a unique contribution comes from laboratory experiments specifically designed to mimic the conditions found in space. We present a review of experimental studies on the formation and evolution of COMs in the solid state, i.e., within ices of astrophysical interest, devoting special attention to the in situ detection and analysis techniques commonly used in laboratory astrochemistry. We discuss their main strengths and weaknesses and provide a perspective view on novel techniques, which may help in overcoming the current experimental challenges.
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Affiliation(s)
- Daniele Fulvio
- Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Naples, Italy
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany; (J.H.); (T.H.)
- Correspondence:
| | - Alexey Potapov
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, 07743 Jena, Germany;
| | - Jiao He
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany; (J.H.); (T.H.)
| | - Thomas Henning
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany; (J.H.); (T.H.)
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8
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Mishra P, Fritz SM, Herbers S, Mebel AM, Zwier TS. Gas-phase pyrolysis of trans 3-pentenenitrile: competition between direct and isomerization-mediated dissociation. Phys Chem Chem Phys 2021; 23:6462-6471. [PMID: 33729262 DOI: 10.1039/d1cp00104c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The flash pyrolysis of trans 3-pentenenitrile (3-PN, CH3-CH[double bond, length as m-dash]CH-CH2-CN) was studied by combining the results of VUV photoionization mass spectra with broadband microwave spectra recorded as a function of the temperature of the pyrolysis tube. The two separated functional groups (vinyl and nitrile) open up isomerization as an initial step in competition with unimolecular dissociation. Primary products were detected by keeping the 3-PN concentration low and limiting reaction times to the traversal time of the gas in the pyrolysis tube (∼100 μs). The reaction is quenched and products are cooled by expansion into vacuum before interrogation over the 8-18 GHz region using chirped-pulse broadband methods. 118 nm VUV photoionization of the same reaction mixture provides a means of detecting all products with ionization potentials below 10.5 eV with minimal fragmentation. These results are combined with a detailed computational investigation of the C5H7N and related potential energy surfaces, leading to a consistent picture of the unimolecular decomposition of 3-PN. Loss of two H-atoms to form a 79 amu product is proven from its microwave transitions to contain trans-Z-2,4-pentadienenitrile, while no pyridine is observed. Methyl loss, HCN loss, and breaking the central C(2)-C(3) bond all occur following isomerization of the position of the double bond, thereby opening up low-energy pathways to these decomposition channels.
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Affiliation(s)
- Piyush Mishra
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393, USA
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9
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Gurusinghe RM, Dias N, Broderick BM. Buffer gas cooling for sensitive rotational spectroscopy of ice chemistry: A proposal. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2020.138125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Pathak S, Obaid R, Bhattacharyya S, Bürger J, Li X, Tross J, Severt T, Davis B, Bilodeau RC, Trallero-Herrero CA, Rudenko A, Berrah N, Rolles D. Differentiating and Quantifying Gas-Phase Conformational Isomers Using Coulomb Explosion Imaging. J Phys Chem Lett 2020; 11:10205-10211. [PMID: 33206545 DOI: 10.1021/acs.jpclett.0c02959] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Conformational isomerism plays a crucial role in defining the physical and chemical properties and biological activity of molecules ranging from simple organic compounds to complex biopolymers. However, it is often a significant challenge to differentiate and separate these isomers experimentally as they can easily interconvert due to their low rotational energy barrier. Here, we use the momentum correlation of fragment ions produced after inner-shell photoionization to distinguish conformational isomers of 1,2-dibromoethane (C2H4Br2). We demonstrate that the three-body breakup channel, C2H4+ + Br+ + Br+, contains signatures of both sequential and concerted breakup, which are decoupled to distinguish the geometries of two conformational isomers and to quantify their relative abundance. The sensitivity of our method to quantify these yields is established by measuring the relative abundance change with sample temperature, which agrees well with calculations. Our study paves the way for using Coulomb explosion imaging to track subtle molecular structural changes.
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Affiliation(s)
- Shashank Pathak
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Razib Obaid
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Surjendu Bhattacharyya
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Johannes Bürger
- Department of Physics, Ludwig Maximilian University of Munich, Munich 80539, Germany
| | - Xiang Li
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Jan Tross
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Travis Severt
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Brandin Davis
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - René C Bilodeau
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | | | - Artem Rudenko
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Nora Berrah
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Daniel Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
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11
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Zou L, Motiyenko RA, Margulès L, Alekseev EA. Millimeter-wave emission spectrometer based on direct digital synthesis. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:063104. [PMID: 32611015 DOI: 10.1063/5.0004461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/31/2020] [Indexed: 06/11/2023]
Abstract
We present a millimeter-wave Fourier transform emission spectrometer whose design is based on the application of a direct digital synthesizer (DDS) up-converted into the Ku-band with subsequent frequency multiplication. The spectrometer covers the frequency range from 50 GHz to 110 GHz and from 150 GHz to 330 GHz. Owing to the fast frequency switching ability of the DDS in the spectrometer, the same radiation source is used both as a generator of short polarizing pulses and as a local oscillator for the heterodyne receiving system. Such a design provides intrinsically coherent reception that allows very long-term data averaging in the time domain, which improves considerably the maximum sensitivity of the spectrometer. The performances of the spectrometer including the data acquisition rate, the sensitivity, and the accuracy of line frequency measurements were tested on the rotational spectra of OCS, NH2CHO, and CH3CH2CN. We show that in the frequency range of 150-300 GHz, the maximum sensitivity of the spectrometer for a 10 min integration time is around 10-9 cm-1 (the minimal value of the absorption coefficient of detectable rotational transition) in the case of narrowband single frequency pulse excitation, and around 10-8 cm-1 in the case of broadband chirped-pulse excitation.
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Affiliation(s)
- Luyao Zou
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - Roman A Motiyenko
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - Laurent Margulès
- Université de Lille, Faculté des Sciences et Technologies, Département Physique, Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, 59655 Villeneuve d'Ascq Cedex, France
| | - Eugen A Alekseev
- Institute of Radio Astronomy of the National Academy of Sciences of Ukraine (IRA NASU), 4, Mystetstv St., Kharkiv 61002, Ukraine
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12
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Abstract
Nonstatistical dynamics is important for many chemical reactions. The Rice-Ramsperger-Kassel-Marcus (RRKM) theory of unimolecular kinetics assumes a reactant molecule maintains a statistical microcanonical ensemble of vibrational states during its dissociation so that its unimolecular dynamics are time independent. Such dynamics results when the reactant's atomic motion is chaotic or irregular. Intrinsic non-RRKM dynamics occurs when part of the reactant's phase space consists of quasiperiodic/regular motion and a bottleneck exists, so that the unimolecular rate constant is time dependent. Nonrandom excitation of a molecule may result in short-time apparent non-RRKM dynamics. For rotational activation, the 2J + 1 K levels for a particular J may be highly mixed, making K an active degree of freedom, or K may be a good quantum number and an adiabatic degree of freedom. Nonstatistical dynamics is often important for bimolecular reactions and their intermediates and for product-energy partitioning of bimolecular and unimolecular reactions. Post–transition state dynamics is often highly complex and nonstatistical.
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Affiliation(s)
- Bhumika Jayee
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
| | - William L. Hase
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
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13
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Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy. Proc Natl Acad Sci U S A 2020; 117:146-151. [PMID: 31852828 DOI: 10.1073/pnas.1911326116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 193-nm photolysis of CH2CHCN illustrates the capability of chirped-pulse Fourier transform millimeter-wave spectroscopy to characterize transition states. We investigate the HCN, HNC photofragments in highly excited vibrational states using both frequency and intensity information. Measured relative intensities of J = 1-0 rotational transition lines yield vibrational-level population distributions (VPD). These VPDs encode the properties of the parent molecule transition state at which the fragment molecule was born. A Poisson distribution formalism, based on the generalized Franck-Condon principle, is proposed as a framework for extracting information about the transition-state structure from the observed VPD. We employ the isotopologue CH2CDCN to disentangle the unimolecular 3-center DCN elimination mechanism from other pathways to HCN. Our experimental results reveal a previously unknown transition state that we tentatively associate with the HCN eliminated via a secondary, bimolecular reaction.
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14
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Karmakar S, Keshavamurthy S. Intramolecular vibrational energy redistribution and the quantum ergodicity transition: a phase space perspective. Phys Chem Chem Phys 2020; 22:11139-11173. [DOI: 10.1039/d0cp01413c] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The onset of facile intramolecular vibrational energy flow can be related to features in the connected network of anharmonic resonances in the classical phase space.
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Affiliation(s)
- Sourav Karmakar
- Department of Chemistry
- Indian Institute of Technology
- Kanpur
- India
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15
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Wu JY, Cheng PY. Ultrafast Protonation of an Amide: Photoionization-Induced Proton Transfer in Phenol-Dimethylformamide Complex Cation. J Phys Chem A 2019; 123:10700-10713. [DOI: 10.1021/acs.jpca.9b09651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Jun-Yi Wu
- Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan, R.
O. C
| | - Po-Yuan Cheng
- Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan, R.
O. C
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16
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Lou X, Yuan Z, Dong Y. Rapid spectroscopic gas sensing using optical linear chirp chain. OPTICS EXPRESS 2019; 27:13160-13171. [PMID: 31052845 DOI: 10.1364/oe.27.013160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Spectroscopic gas analysis for monitoring transient events in fast processes requires high spectrum acquisition rate with low uncertainty; however, so far high-speed spectroscopic gas detection with sufficient spectral resolution and spectral span is still challenging. Here, we propose an innovative method based on optical linear chirp chain (OLCC) for rapid acquisition of high-resolution gas spectra with a rate up to the order of MHz with 100% duty cycle, spectral resolution at 10-MHz level and spectral span > 20 GHz. The OLCC is generated by high-speed optical modulation driven by a digital arbitrary waveform generator in combination with a four-wave-mixing process, exhibiting a highly linear frequency chirp (linearity error of ~10-4) and low level of residual amplitude modulation (<1%). An image denoising method based on nonlocal means algorithm is exploited to reduce the high-frequency noise while guaranteeing the response time and spectral resolution. We demonstrate this method by monitoring a fast charging process of acetylene gas into a vacuumized gas cell, clearly unfolding gas pressure oscillations at μs time scale. Our proposed OLCC-based spectroscopic method opens up prospects for the development of high-speed spectrometers and optical sensors.
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17
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Karmakar S, Keshavamurthy S. Relevance of the Resonance Junctions on the Arnold Web to Dynamical Tunneling and Eigenstate Delocalization. J Phys Chem A 2018; 122:8636-8649. [PMID: 30289718 DOI: 10.1021/acs.jpca.8b08626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We study the competition and correspondence between the classical and quantum routes to intramolecular vibrational energy redistribution (IVR) in a three degrees of freedom model effective Hamiltonian. Specifically, we focus on the classical and the quantum dynamics near the resonance junctions on the Arnold web that are formed by an intersection of independent resonances. The regime of interest models the IVR dynamics from highly excited initial states near dissociation thresholds of molecular systems wherein both classical and purely quantum, involving dynamical tunneling, routes to IVR coexist. In the vicinity of a resonance junction, classical chaos is inevitably present, and hence one expects the quantum IVR pathways to have a strong classical component as well. We show that with increasing resonant coupling strengths the classical component of IVR leads to a transition from coherent dynamical tunneling to incoherent dynamical tunneling. Furthermore, we establish that the quantum IVR dynamics can be predicted based on the structures on the classical Arnold web. In addition, we investigate the nature of the highly excited eigenstates to identify the quantum signatures of the multiplicity-2 junctions. For the parameter regimes studies herein, by projecting the eigenstates onto the Arnold web, we find that eigenstates in the vicinity of the junctions are primarily delocalized due to dynamical tunneling.
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Affiliation(s)
- Sourav Karmakar
- Department of Chemistry , Indian Institute of Technology , Kanpur , Uttar Pradesh 208 016 , India
| | - Srihari Keshavamurthy
- Department of Chemistry , Indian Institute of Technology , Kanpur , Uttar Pradesh 208 016 , India
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18
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Zaleski DP, Prozument K. Automated assignment of rotational spectra using artificial neural networks. J Chem Phys 2018; 149:104106. [DOI: 10.1063/1.5037715] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel P. Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
USA
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
USA
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19
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Fritz SM, Hays BM, Hernandez-Castillo AO, Abeysekera C, Zwier TS. Multiplexed characterization of complex gas-phase mixtures combining chirped-pulse Fourier transform microwave spectroscopy and VUV photoionization time-of-flight mass spectrometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:093101. [PMID: 30278727 DOI: 10.1063/1.5046085] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/14/2018] [Indexed: 06/08/2023]
Abstract
We report details of the design and operation of a single apparatus that combines Chirped-Pulse Fourier Transform Microwave (CP-FTMW) spectroscopy with vacuum ultraviolet (VUV) photoionization Time-of-Flight Mass Spectrometry (TOFMS). The supersonic expansion used for cooling samples is interrogated first by passing through the region between two microwave horns capable of broadband excitation and detection in the 2-18 GHz frequency region of the microwave. After passing through this region, the expansion is skimmed to form a molecular beam, before being probed with 118 nm (10.5 eV) single-photon VUV photoionization in a linear time-of-flight mass spectrometer. The two detection schemes are powerfully complementary to one another. CP-FTMW detects all components with significant permanent dipole moments. Rotational transitions provide high-resolution structural data. VUV TOFMS provides a gentle and general method for ionizing all components of a gas phase mixture with ionization thresholds below 10.5 eV, providing their molecular formulae. The advantages, complementarity, and limitations of the combined methods are illustrated through results on two gas-phase mixtures made up of (i) three furanic compounds, two of which are structural isomers of one another, and (ii) the effluent from a flash pyrolysis source with o-guaiacol as the precursor.
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Affiliation(s)
- Sean M Fritz
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Brian M Hays
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | | | - Chamara Abeysekera
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
| | - Timothy S Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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Harrilal CP, DeBlase AF, Fischer JL, Lawler JT, McLuckey SA, Zwier TS. Infrared Population Transfer Spectroscopy of Cryo-Cooled Ions: Quantitative Tests of the Effects of Collisional Cooling on the Room Temperature Conformer Populations. J Phys Chem A 2018; 122:2096-2107. [PMID: 29464953 DOI: 10.1021/acs.jpca.7b12751] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher P. Harrilal
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Andrew F. DeBlase
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Joshua L. Fischer
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - John T. Lawler
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
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21
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Patra S, Keshavamurthy S. Detecting reactive islands using Lagrangian descriptors and the relevance to transition path sampling. Phys Chem Chem Phys 2018; 20:4970-4981. [PMID: 29387842 DOI: 10.1039/c7cp05912d] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It has been known for sometime now that isomerization reactions, classically, are mediated by phase space structures called reactive islands (RI). RIs provide one possible route to correct for the nonstatistical effects in the reaction dynamics. In this work, we map out the reactive islands for the two dimensional Müller-Brown model potential and show that the reactive islands are intimately linked to the issue of rare event sampling. In particular, we establish the sensitivity of the so called committor probabilities, useful quantities in the transition path sampling technique, to the hierarchical RI structures. Mapping out the RI structure for high dimensional systems, however, is a challenging task. Here, we show that the technique of Lagrangian descriptors is able to effectively identify the RI hierarchy in the model system. Based on our results, we suggest that the Lagrangian descriptors can be useful for detecting RIs in high dimensional systems.
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Affiliation(s)
- Sarbani Patra
- Department of Chemistry, Indian Institute of Technology, Kanpur, U.P. 208 016, India.
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22
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Tanarro I, Alemán B, de Vicente P, Gallego JD, Pardo JR, Santoro G, Lauwaet K, Tercero F, Díaz-Pulido A, Moreno E, Agúndez M, Goicoechea JR, Sobrado JM, López JA, Martínez L, Doménech JL, Herrero VJ, Hernández JM, Peláez RJ, López-Pérez JA, Gómez-González J, Alonso JL, Jiménez E, Teyssier D, Makasheva K, Castellanos M, Joblin C, Martín-Gago JA, Cernicharo J. Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept. ASTRONOMY AND ASTROPHYSICS 2018; 609:A15. [PMID: 29277841 PMCID: PMC5741178 DOI: 10.1051/0004-6361/201730969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41-49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (<10-3 mbar) were detected in a few seconds. Fast data acquisition was achieved allowing for kinetic measurements in fragmentation experiments using electron impact or UV irradiation. Time evolution of chemical reactions involving OCS, O2 and CS2 was also observed demonstrating that reactive species, such as CS, can be maintained with high abundance in the gas phase during these experiments.
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Affiliation(s)
- I Tanarro
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - B Alemán
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - P de Vicente
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J D Gallego
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J R Pardo
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - G Santoro
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - K Lauwaet
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - F Tercero
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - A Díaz-Pulido
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - E Moreno
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - M Agúndez
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J R Goicoechea
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J M Sobrado
- Centro de Astrobiología, (CAB-CSIC/INTA). Carretera Torrejón a Ajalvir km 4, Torrejón de Ardoz 28850 (Madrid), Spain
| | - J A López
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - L Martínez
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J L Doménech
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - V J Herrero
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J M Hernández
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - R J Peláez
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J A López-Pérez
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J Gómez-González
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J L Alonso
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - E Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, E-13071, Ciudad Real, Spain
| | - D Teyssier
- European Space Astronomy Centre, ESA, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
| | - K Makasheva
- LAPLACE (Laboratoire Plasma et Conversion dÉnergie); Université de Toulouse; CNRS, UPS, INPT; 118 route de Narbonne, F-31062 Toulouse cedex 9, France
| | - M Castellanos
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - C Joblin
- Université de Toulouse, UPS-OMS, IRAP, 31000 Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - J A Martín-Gago
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J Cernicharo
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
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23
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Zaleski DP, Harding LB, Klippenstein SJ, Ruscic B, Prozument K. Time-Resolved Kinetic Chirped-Pulse Rotational Spectroscopy in a Room-Temperature Flow Reactor. J Phys Chem Lett 2017; 8:6180-6188. [PMID: 29193976 DOI: 10.1021/acs.jpclett.7b02864] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chirped-pulse Fourier transform millimeter-wave spectroscopy is a potentially powerful tool for studying chemical reaction dynamics and kinetics. Branching ratios of multiple reaction products and intermediates can be measured with unprecedented chemical specificity; molecular isomers, conformers, and vibrational states have distinct rotational spectra. Here we demonstrate chirped-pulse spectroscopy of vinyl cyanide photoproducts in a flow tube reactor at ambient temperature of 295 K and pressures of 1-10 μbar. This in situ and time-resolved experiment illustrates the utility of this novel approach to investigating chemical reaction dynamics and kinetics. Following 193 nm photodissociation of CH2CHCN, we observe rotational relaxation of energized HCN, HNC, and HCCCN photoproducts with 10 μs time resolution and sample the vibrational population distribution of HCCCN. The experimental branching ratio HCN/HCCCN is compared with a model based on RRKM theory using high-level ab initio calculations, which were in turn validated by comparisons to Active Thermochemical Tables enthalpies.
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Affiliation(s)
- Daniel P Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Lawrence B Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
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24
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Grimes DD, Barnum TJ, Zhou Y, Colombo AP, Field RW. Coherent laser-millimeter-wave interactions en route to coherent population transfer. J Chem Phys 2017; 147:144201. [DOI: 10.1063/1.4997624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David D. Grimes
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Timothy J. Barnum
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yan Zhou
- JILA, National Institute of Standards and Technology, Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Anthony P. Colombo
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert W. Field
- Department of Chemistry, Massaschusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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25
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Potapov A, Canosa A, Jiménez E, Rowe B. Chemie mit Überschall: 30 Jahre astrochemische Forschung und künftige Herausforderungen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexey Potapov
- Laborastrophysikgruppe des Max-Planck-Instituts für Astronomie am Institut für Festkörperphysik; Friedrich-Schiller-Universität Jena; Helmholtzweg 3 07743 Jena Deutschland
| | - André Canosa
- Département de Physique Moléculaire; Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, Campus de Beaulieu; 263 Avenue du Général Leclerc 35042 Rennes Cedex Frankreich
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas; Universidad de Castilla-La Mancha; Avda. Camilo José Cela, 1B 13071 Ciudad Real Spanien
| | - Bertrand Rowe
- Rowe-consulting, 22 Chemin des Moines; 22750 Saint Jacut de la Mer Frankreich
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26
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Zhu GZ, Huang DL, Wang LS. Conformation-selective resonant photoelectron imaging from dipole-bound states of cold 3-hydroxyphenoxide. J Chem Phys 2017; 147:013910. [DOI: 10.1063/1.4979331] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Guo-Zhu Zhu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Dao-Ling Huang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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27
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Potapov A, Canosa A, Jiménez E, Rowe B. Uniform Supersonic Chemical Reactors: 30 Years of Astrochemical History and Future Challenges. Angew Chem Int Ed Engl 2017; 56:8618-8640. [DOI: 10.1002/anie.201611240] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/27/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Alexey Potapov
- Laborastrophysikgruppe des Max-Planck-Instituts für Astronomie am Institut für Festkörperphysik; Friedrich-Schiller-Universität Jena; Helmholtzweg 3 07743 Jena Germany
| | - André Canosa
- Département de Physique Moléculaire; Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, Campus de Beaulieu; 263 Avenue du Général Leclerc 35042 Rennes Cedex France
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas; Universidad de Castilla-La Mancha; Avda. Camilo José Cela, 1B 13071 Ciudad Real Spain
| | - Bertrand Rowe
- Rowe-consulting, 22 Chemin des Moines; 22750 Saint Jacut de la Mer France
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28
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Grubbs G. The carbon mainframe structure of cis-trans-1,3-difluoroacetone. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.08.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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29
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Hernandez-Castillo AO, Abeysekera C, Hays BM, Zwier TS. Broadband multi-resonant strong field coherence breaking as a tool for single isomer microwave spectroscopy. J Chem Phys 2016. [DOI: 10.1063/1.4962505] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Chamara Abeysekera
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, USA
| | - Brian M. Hays
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, USA
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, USA
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30
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Park GB, Field RW. Perspective: The first ten years of broadband chirped pulse Fourier transform microwave spectroscopy. J Chem Phys 2016; 144:200901. [DOI: 10.1063/1.4952762] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- G. Barratt Park
- Institute for Physical Chemistry, University of Göttingen, Tammannstraße 6, 37077 Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, Göttingen, Am Faßberg 11, 37077 Göttingen, Germany
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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31
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Gadogbe M, Zhou Y, Zou S, Zhang D. Rigid Single Carbon-Carbon Bond That Does Not Rotate in Water. J Phys Chem B 2016; 120:2418-22. [PMID: 26882311 DOI: 10.1021/acs.jpcb.5b12166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carbon-carbon bond is one of the most ubiquitous molecular building blocks for natural and man-made materials. Rotational isomerization is fundamentally important for understanding the structure and reactivity of chemical and biological molecules. Reported herein is the first demonstration that a single C-C bond does not rotate in water. The two distal C-S bonds in both 1,2-ethanedithiolate ((-)S-CH2-CH2-S(-), 1,2-EDT(2-)) and 2,3-butanedithiolate (2,3-BuDT(2-)) are exclusively in the trans conformer with reference to their respective center single C-C bond. In contrast, both trans and gauche conformers are observed in neutral 1,2-ethanedithiol (1,2-EDT) and 2, 3-butanedithiol (2,3-BuDT). The insight from this work should be important for understanding the charge effect on the molecular conformation in aqueous solutions.
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Affiliation(s)
- Manuel Gadogbe
- Department of Chemistry, Mississippi State University , Mississippi State, Mississippi 39762, United States
| | - Yadong Zhou
- Department of Chemistry, University of Central Florida , Orlando, Florida 32816, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida , Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University , Mississippi State, Mississippi 39762, United States
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32
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Shubert VA, Schmitz D, Pérez C, Medcraft C, Krin A, Domingos SR, Patterson D, Schnell M. Chiral Analysis Using Broadband Rotational Spectroscopy. J Phys Chem Lett 2016; 7:341-350. [PMID: 26745342 DOI: 10.1021/acs.jpclett.5b02443] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
broadband microwave spectroscopy is a proven tool to precisely determine molecular properties of gas-phase molecules. Recent developments make it applicable to investigate chiral molecules. Enantiomers can be differentiated, and the enantiomeric excess and, indirectly, the absolute configuration can be determined in a molecule-selective manner. The resonant character and high resolution of rotational spectroscopy provide a unique mixture compatibility. Future directions, such as extending the technique to chemical analysis, are discussed.
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Affiliation(s)
- V Alvin Shubert
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - David Schmitz
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Cristóbal Pérez
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Chris Medcraft
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Anna Krin
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Sérgio R Domingos
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - David Patterson
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Melanie Schnell
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg , Luruper Chaussee 149, D-22761 Hamburg, Germany
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33
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Direct detection of Rydberg–Rydberg millimeter-wave transitions in a buffer gas cooled molecular beam. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Wilhelm MJ, Smith JM, Dai HL. Spectral reconstruction analysis for enhancing signal-to-noise in time-resolved spectroscopies. J Chem Phys 2015; 143:124204. [DOI: 10.1063/1.4931581] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael J. Wilhelm
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, Pennsylvania 19122, USA
| | - Jonathan M. Smith
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, Pennsylvania 19122, USA
| | - Hai-Lung Dai
- Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, Pennsylvania 19122, USA
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35
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Classical-quantum correspondence in a model for conformational dynamics: Connecting phase space reactive islands with rare events sampling. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.05.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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36
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Abeysekera C, Zack LN, Park GB, Joalland B, Oldham JM, Prozument K, Ariyasingha NM, Sims IR, Field RW, Suits AG. A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. II. Performance and applications for reaction dynamics. J Chem Phys 2015; 141:214203. [PMID: 25481137 DOI: 10.1063/1.4903253] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This second paper in a series of two reports on the performance of a new instrument for studying chemical reaction dynamics and kinetics at low temperatures. Our approach employs chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy to probe photolysis and bimolecular reaction products that are thermalized in pulsed uniform flows. Here we detail the development and testing of a new K(a)-band CP-FTMW spectrometer in combination with the pulsed flow system described in Paper I [J. M. Oldham, C. Abeysekera, B. Joalland, L. N. Zack, K. Prozument, I. R. Sims, G. B. Park, R. W. Field, and A. G. Suits, J. Chem. Phys. 141, 154202 (2014)]. This combination delivers broadband spectra with MHz resolution and allows monitoring, on the μs timescale, of the appearance of transient reaction products. Two benchmark reactive systems are used to illustrate and characterize the performance of this new apparatus: the photodissociation of SO2 at 193 nm, for which the vibrational populations of the SO product are monitored, and the reaction between CN and C2H2, for which the HCCCN product is detected in its vibrational ground state. The results show that the combination of these two well-matched techniques, which we refer to as chirped-pulse in uniform flow, also provides insight into the vibrational and rotational relaxation kinetics of the nascent reaction products. Future directions are discussed, with an emphasis on exploring the low temperature chemistry of complex polyatomic systems.
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Affiliation(s)
- Chamara Abeysekera
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Lindsay N Zack
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - G Barratt Park
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Baptiste Joalland
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - James M Oldham
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Kirill Prozument
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Nuwandi M Ariyasingha
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Ian R Sims
- Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, 263 Avenue du Général Leclerc, 35042, Rennes Cedex, France
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Arthur G Suits
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
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Huang DL, Liu HT, Ning CG, Wang LS. Conformation-Selective Resonant Photoelectron Spectroscopy via Dipole-Bound States of Cold Anions. J Phys Chem Lett 2015; 6:2153-2157. [PMID: 26266584 DOI: 10.1021/acs.jpclett.5b00963] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Molecular conformation is important in chemistry and biochemistry. Conformers connected by low energy barriers can only be observed at low temperatures and are difficult to be separated. Here we report a new method to obtain conformation-selective spectroscopic information about dipolar molecular radicals via dipole-bound excited states of the corresponding anions cooled in a cryogenic ion trap. We observed two conformers of cold 3-hydroxyphenoxide anions [m-HO(C6H4)O(-)] in high-resolution photoelectron spectroscopy and measured different electron affinities, 18,850(8) and 18,917(5) cm(-1), for the syn and anti 3-hydroxyphenoxy radicals, respectively. We also observed dipole-bound excited states for m-HO(C6H4)O(-) with different binding energies for the two conformers due to the different dipole moments of the corresponding 3-hydroxyphenoxy radicals. Excitations to selected vibrational levels of the dipole-bound states result in conformation-selective photoelectron spectra. This method should be applicable to conformation-selective spectroscopic studies of any anions with dipolar neutral cores.
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Affiliation(s)
- Dao-Ling Huang
- †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hong-Tao Liu
- ‡Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Chuan-Gang Ning
- §Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Lai-Sheng Wang
- †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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38
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Prozument K, Barratt Park G, Shaver RG, Vasiliou AK, Oldham JM, David DE, Muenter JS, Stanton JF, Suits AG, Barney Ellison G, Field RW. Chirped-Pulse millimeter-Wave spectroscopy for dynamics and kinetics studies of pyrolysis reactions. Phys Chem Chem Phys 2015; 16:15739-15751. [PMID: 24756159 DOI: 10.1039/c3cp55352c] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A Chirped-Pulse millimeter-Wave (CPmmW) spectrometer is applied to the study of chemical reaction products that result from pyrolysis in a Chen nozzle heated to 1000-1800 K. Millimeter-wave rotational spectroscopy unambiguously determines, for each polar reaction product, the species, the conformers, relative concentrations, conversion percentage from precursor to each product, and, in some cases, vibrational state population distributions. A chirped-pulse spectrometer can, within the frequency range of a single chirp, sample spectral regions of up to ∼10 GHz and simultaneously detect many reaction products. Here we introduce a modification to the CPmmW technique in which multiple chirps of different spectral content are applied to a molecular beam pulse that contains the pyrolysis reaction products. This technique allows for controlled allocation of its sensitivity to specific molecular transitions and effectively doubles the bandwidth of the spectrometer. As an example, the pyrolysis reaction of ethyl nitrite, CH3CH2ONO, is studied, and CH3CHO, H2CO, and HNO products are simultaneously observed and quantified, exploiting the multi-chirp CPmmW technique. Rotational and vibrational temperatures of some product molecules are determined. Subsequent to supersonic expansion from the heated nozzle, acetaldehyde molecules display a rotational temperature of 4 ± 1 K. Vibrational temperatures are found to be controlled by the collisional cooling in the expansion, and to be both species- and vibrational mode-dependent. Rotational transitions of vibrationally excited formaldehyde in levels ν4, 2ν4, 3ν4, ν2, ν3, and ν6 are observed and effective vibrational temperatures for modes 2, 3, 4, and 6 are determined and discussed.
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Affiliation(s)
- Kirill Prozument
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. and Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - G Barratt Park
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Rachel G Shaver
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - AnGayle K Vasiliou
- Department of Chemistry and Biochemistry, Middlebury College, 276 Bicentennial Way, Middlebury, VT 05753, USA
| | - James M Oldham
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - Donald E David
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Cristol Chemistry 58, Boulder, CO 80309, USA
| | - John S Muenter
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627, USA
| | - John F Stanton
- Department of Chemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-0165, USA
| | - Arthur G Suits
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - G Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Cristol Chemistry 58, Boulder, CO 80309, USA
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
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39
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Abeysekera C, Joalland B, Ariyasingha N, Zack LN, Sims IR, Field RW, Suits AG. Product Branching in the Low Temperature Reaction of CN with Propyne by Chirped-Pulse Microwave Spectroscopy in a Uniform Supersonic Flow. J Phys Chem Lett 2015; 6:1599-1604. [PMID: 26263320 DOI: 10.1021/acs.jpclett.5b00519] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A new chirped-pulse/uniform flow (CPUF) spectrometer has been developed and used to determine product branching in a multichannel reaction. With this technique, bimolecular reactions can be initiated in a cold, thermalized, high-density molecular flow and a broadband microwave spectrum acquired for all products with rotational transitions within a chosen frequency window. In this work, the CN + CH3CCH reaction was found to yield HCN via a direct H-abstraction reaction, whereas indirect addition/elimination pathways to HCCCN, CH3CCCN, and CH2CCHCN were also probed. From these observations, quantitative branching ratios were established for all products as 12(5)%, 66(4)%, 22(6)%, and 0(8)% into HCN, HCCCN, CH3CCCN, and CH2CCHCN, respectively. The values are consistent with statistical calculations based on new ab initio results at the CBS-QB3 level of theory. This work is a demonstration of CPUF as a powerful technique for quantitatively determining the branching into polyatomic products from a bimolecular reaction.
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Affiliation(s)
- Chamara Abeysekera
- †Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Baptiste Joalland
- †Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Nuwandi Ariyasingha
- †Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Lindsay N Zack
- †Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Ian R Sims
- ‡Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, 263 Avenue du Général Leclerc, 35042, Rennes CEDEX, France
| | - Robert W Field
- §Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Arthur G Suits
- †Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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40
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Schmitz D, Shubert VA, Patterson D, Krin A, Schnell M. Phase Dependence of Double-Resonance Experiments in Rotational Spectroscopy. J Phys Chem Lett 2015; 6:1493-1498. [PMID: 26263157 DOI: 10.1021/acs.jpclett.5b00494] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We here report on double-resonance experiments using broadband chirped pulse Fourier transform microwave spectroscopy that can facilitate spectral assignment and yield information about weak transitions with high resolution and sensitivity. Using the diastereomers menthone and isomenthone, we investigate the dependence of pumping a radio frequency transition on both the amplitude and phase of the signal from a microwave transition with which it shares a common rotational level. We observe a strong phase change when scanning the radio frequency through molecular resonance. The direction of the phase change depends on the energy level arrangement, that is, if it is progressive or regressive. The experimental results can be simulated using the three-level optical Bloch equations and described with the AC Stark effect, giving rise to an Autler-Townes splitting.
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Affiliation(s)
- David Schmitz
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - V Alvin Shubert
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - David Patterson
- ¶Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Anna Krin
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Melanie Schnell
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
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41
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Park GB, Womack CC, Whitehill AR, Jiang J, Ono S, Field RW. Millimeter-wave optical double resonance schemes for rapid assignment of perturbed spectra, with applications to the C̃1B2 state of SO2. J Chem Phys 2015; 142:144201. [DOI: 10.1063/1.4916908] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- G. Barratt Park
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Caroline C. Womack
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Andrew R. Whitehill
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jun Jiang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Shuhei Ono
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Abstract
Unimolecular dissociation dynamics of a model three degree of freedom triatomic molecule is studied in order to understand the mechanisms for deviations from statisticality. Performing a wavelet based time–frequency analysis of the dynamics allows for the dynamics to be followed on the network of nonlinear resonances, also called as the Arnold web. The results indicate that the long lifetime trajectories spend a considerable amount of time trapped near junctions in the web. It is argued that characterizing the dynamics near such junctions might lead to deeper insights into the origins of nonstatistical dynamics.
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43
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Prozument K, Suleimanov YV, Buesser B, Oldham JM, Green WH, Suits AG, Field RW. A Signature of Roaming Dynamics in the Thermal Decomposition of Ethyl Nitrite: Chirped-Pulse Rotational Spectroscopy and Kinetic Modeling. J Phys Chem Lett 2014; 5:3641-3648. [PMID: 26278732 DOI: 10.1021/jz501758p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chirped-pulse (CP) Fourier transform rotational spectroscopy is uniquely suited for near-universal quantitative detection and structural characterization of mixtures that contain multiple molecular and radical species. In this work, we employ CP spectroscopy to measure product branching and extract information about the reaction mechanism, guided by kinetic modeling. Pyrolysis of ethyl nitrite, CH3CH2ONO, is studied in a Chen type flash pyrolysis reactor at temperatures of 1000-1800 K. The branching between HNO, CH2O, and CH3CHO products is measured and compared to the kinetic models generated by the Reaction Mechanism Generator software. We find that roaming CH3CH2ONO → CH3CHO + HNO plays an important role in the thermal decomposition of ethyl nitrite, with its rate, at 1000 K, comparable to that of the radical elimination channel CH3CH2ONO → CH3CH2O + NO. HNO is a signature of roaming in this system.
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Affiliation(s)
| | | | - Beat Buesser
- §IBM Research, Smarter Cities Technology Centre, Dublin 15, Ireland
| | - James M Oldham
- ∥Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - Arthur G Suits
- ∥Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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44
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Oldham JM, Abeysekera C, Joalland B, Zack LN, Prozument K, Sims IR, Park GB, Field RW, Suits AG. A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. I. The low-temperature flow system. J Chem Phys 2014; 141:154202. [DOI: 10.1063/1.4897979] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- James M. Oldham
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Chamara Abeysekera
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Baptiste Joalland
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Lindsay N. Zack
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Kirill Prozument
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Ian R. Sims
- Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, 263 Avenue du Général Leclerc, 35042 Rennes Cedex, France
| | - G. Barratt Park
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Arthur G. Suits
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
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45
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Manikandan P, Keshavamurthy S. Dynamical traps lead to the slowing down of intramolecular vibrational energy flow. Proc Natl Acad Sci U S A 2014; 111:14354-9. [PMID: 25246538 PMCID: PMC4209979 DOI: 10.1073/pnas.1406630111] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The phenomenon of intramolecular vibrational energy redistribution (IVR) is at the heart of chemical reaction dynamics. Statistical rate theories, assuming instantaneous IVR, predict exponential decay of the population with the properties of the transition state essentially determining the mechanism. However, there is growing evidence that IVR competes with the reaction timescales, resulting in deviations from the exponential rate law. Dynamics cannot be ignored in such cases for understanding the reaction mechanisms. Significant insights in this context have come from the state space model of IVR, which predicts power law behavior for the rates with the power law exponent, an effective state space dimensionality, being a measure of the nature and extent of the IVR dynamics. However, whether the effective IVR dimensionality can vary with time and whether the mechanism for the variation is of purely quantum or classical origins are issues that remain unresolved. Such multiple power law scalings can lead to surprising mode specificity in the system, even above the threshold for facile IVR. In this work, choosing the well-studied thiophosgene molecule as an example, we establish the anisotropic and anomalous nature of the quantum IVR dynamics and show that multiple power law scalings do manifest in the system. More importantly, we show that the mechanism of the observed multiple power law scaling has classical origins due to a combination of trapping near resonance junctions in the network of classical nonlinear resonances at short to intermediate times and the influence of weak higher-order resonances at relatively longer times.
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Affiliation(s)
- Paranjothy Manikandan
- Department of Chemistry, Indian Institute of Technology, Kanpur (U.P.) 208016, India
| | - Srihari Keshavamurthy
- Department of Chemistry, Indian Institute of Technology, Kanpur (U.P.) 208016, India
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46
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Rösch D, Willitsch S, Chang YP, Küpper J. Chemical reactions of conformationally selected 3-aminophenol molecules in a beam with Coulomb-crystallized Ca+ ions. J Chem Phys 2014; 140:124202. [PMID: 24697433 DOI: 10.1063/1.4869100] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel Rösch
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Stefan Willitsch
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Yuan-Pin Chang
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
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47
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Chang YP, Długołęcki K, Küpper J, Rösch D, Wild D, Willitsch S. Specific Chemical Reactivities of Spatially Separated 3-Aminophenol Conformers with Cold Ca+ Ions. Science 2013; 342:98-101. [DOI: 10.1126/science.1242271] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Many molecules exhibit multiple rotational isomers (conformers) that interconvert thermally and are difficult to isolate. Consequently, a precise characterization of their role in chemical reactions has proven challenging. We have probed the reactivity of specific conformers by using an experimental technique based on their spatial separation in a molecular beam by electrostatic deflection. The separated conformers react with a target of Coulomb-crystallized ions in a trap. In the reaction of Ca+ with 3-aminophenol, we find a twofold larger rate constant for the cis compared with the trans conformer (differentiated by the O–H bond orientation). This result is explained by conformer-specific differences in the long-range ion-molecule interaction potentials. Our approach demonstrates the possibility of controlling reactivity through selection of conformational states.
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48
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Peña I, Cocinero EJ, Cabezas C, Lesarri A, Mata S, Écija P, Daly AM, Cimas Á, Bermúdez C, Basterretxea FJ, Blanco S, Fernández JA, López JC, Castaño F, Alonso JL. Six Pyranoside Forms of Free 2-Deoxy-D-ribose. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305589] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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49
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Peña I, Cocinero EJ, Cabezas C, Lesarri A, Mata S, Écija P, Daly AM, Cimas Á, Bermúdez C, Basterretxea FJ, Blanco S, Fernández JA, López JC, Castaño F, Alonso JL. Six Pyranoside Forms of Free 2-Deoxy-D-ribose. Angew Chem Int Ed Engl 2013; 52:11840-5. [DOI: 10.1002/anie.201305589] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Indexed: 11/09/2022]
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50
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Finneran IA, Holland DB, Carroll PB, Blake GA. A direct digital synthesis chirped pulse Fourier transform microwave spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:083104. [PMID: 24007050 DOI: 10.1063/1.4818137] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Chirped pulse Fourier transform microwave (CP-FTMW) spectrometers have become the instrument of choice for acquiring rotational spectra, due to their high sensitivity, fast acquisition rate, and large bandwidth. Here we present the design and capabilities of a recently constructed CP-FTMW spectrometer using direct digital synthesis (DDS) as a new method for chirped pulse generation, through both a suite of extensive microwave characterizations and deep averaging of the 10-14 GHz spectrum of jet-cooled acetone. The use of DDS is more suited for in situ applications of CP-FTMW spectroscopy, as it reduces the size, weight, and power consumption of the chirp generation segment of the spectrometer all by more than an order of magnitude, while matching the performance of traditional designs. The performance of the instrument was further improved by the use of a high speed digitizer with dedicated signal averaging electronics, which facilitates a data acquisition rate of 2.1 kHz.
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Affiliation(s)
- Ian A Finneran
- Department of Chemistry, California Institute of Technology, Pasadena, California 91125, USA
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