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Gardner MB, Westbrook BR, Fortenberry RC, Lee TJ. Highly-accurate quartic force fields for the prediction of anharmonic rotational constants and fundamental vibrational frequencies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 248:119184. [PMID: 33293226 DOI: 10.1016/j.saa.2020.119184] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/29/2020] [Accepted: 11/01/2020] [Indexed: 06/12/2023]
Abstract
The CcCR quartic force field (QFF) methodology is capable of computing B0 and C0 rotational constants to within 35 MHz (0.14%) of experiment for triatomic and larger molecules with at least two heavy atoms. Additionally, the same constants for molecules with four or more atoms agree to within 20 MHz (0.12%) of experiment for the current test set. This work also supports previous claims that the same QFF methodology can produce fundamental vibrational frequencies with a deviation less than 5.7 cm-1 from experiment. Consequently, this approach of augmenting complete basis set extrapolated energies with treatments of core electron correlation and scalar relativity produces some of the most accurate rovibrational spectroscopic data available.
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Affiliation(s)
- Mason B Gardner
- Department of Chemistry & Biochemistry, University of Mississippi, University, MS 38677-1848, United States
| | - Brent R Westbrook
- Department of Chemistry & Biochemistry, University of Mississippi, University, MS 38677-1848, United States
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, University, MS 38677-1848, United States.
| | - Timothy J Lee
- MS 245-3, NASA Ames Research Center, Moffett Field, CA 94035, United States
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2
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Khalouf-Rivera J, Carvajal M, Santos LF, Pérez-Bernal F. Calculation of Transition State Energies in the HCN–HNC Isomerization with an Algebraic Model. J Phys Chem A 2019; 123:9544-9551. [DOI: 10.1021/acs.jpca.9b07338] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jamil Khalouf-Rivera
- Depto. de Ciencias Integradas y Centro de Estudios Avanzados en Física, Matemáticas y Computación, Universidad de Huelva, Huelva 21071, Spain
| | - Miguel Carvajal
- Depto. de Ciencias Integradas y Centro de Estudios Avanzados en Física, Matemáticas y Computación, Universidad de Huelva, Huelva 21071, Spain
- Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Granada 18071, Spain
| | - Lea F. Santos
- Department of Physics, Yeshiva University, New York, New York 10016, United States
| | - Francisco Pérez-Bernal
- Depto. de Ciencias Integradas y Centro de Estudios Avanzados en Física, Matemáticas y Computación, Universidad de Huelva, Huelva 21071, Spain
- Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Granada 18071, Spain
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Georges R, Thiévin J, Benidar A, Carles S, Amyay B, Louviot M, Boudon V, Vander Auwera J. High enthalpy source dedicated to quantitative infrared emission spectroscopy of gas flows at elevated temperatures. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:093103. [PMID: 31575252 DOI: 10.1063/1.5097696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
The High Enthalpy Source (HES) is a novel high temperature source developed to measure infrared line-by-line integrated absorption cross sections of flowing gases up to 2000 K. The HES relies on a porous graphite furnace designed to uniformly heat a constant flow of gas. The flow compensates thermal dissociation by renewing continuously the gas sample and eliminating dissociation products. The flowing characteristics have been investigated using computational fluid dynamics simulation confirming good temperature uniformity. The HES has been coupled to a high-resolution Fourier transform spectrometer to record emission spectra of methane at temperatures ranging between 700 and 1400 K. A radiative model has been developed to extract absolute line intensities from the recorded spectra.
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Affiliation(s)
- R Georges
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Thiévin
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - A Benidar
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - S Carles
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - B Amyay
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS, Université Bourgogne Franche-Comté, 9 avenue A. Savary, BP 47870, 21078 Dijon Cedex, France
| | - M Louviot
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS, Université Bourgogne Franche-Comté, 9 avenue A. Savary, BP 47870, 21078 Dijon Cedex, France
| | - V Boudon
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS, Université Bourgogne Franche-Comté, 9 avenue A. Savary, BP 47870, 21078 Dijon Cedex, France
| | - J Vander Auwera
- Service de Chimie Quantique et Photophysique, C.P. 160/09, Université Libre de Bruxelles, 50 avenue F. D. Roosevelt, B-1050 Brussels, Belgium
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Makhnev VY, Kyuberis AA, Zobov NF, Lodi L, Tennyson J, Polyansky OL. High Accuracy ab Initio Calculations of Rotational-Vibrational Levels of the HCN/HNC System. J Phys Chem A 2018; 122:1326-1343. [PMID: 29251934 DOI: 10.1021/acs.jpca.7b10483] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Highly accurate ab initio calculations of vibrational and rotational-vibrational energy levels of the HCN/HNC (hydrogen cyanide/hydrogen isocyanide) isomerising system are presented for several isotopologues. All-electron multireference configuration interaction (MRCI) electronic structure calculations were performed using basis sets up to aug-cc-pCV6Z on a grid of 1541 geometries. The ab initio energies were used to produce an analytical potential energy surface (PES) describing the two minima simultaneously. An adiabatic Born-Oppenheimer diagonal correction (BODC) correction surface as well as a relativistic correction surface were also calculated. These surfaces were used to compute vibrational and rotational-vibrational energy levels up to 25 000 cm-1 which reproduce the extensive set of experimentally known HCN/HNC levels with a root-mean-square deviation σ = 1.5 cm-1. We studied the effect of nonadiabatic effects by introducing opportune radial and angular corrections to the nuclear kinetic energy operator. Empirical determination of two nonadiabatic parameters results in observed energies up to 7000 cm-1 for four HCN isotopologues (HCN, DCN, H13CN, and HC15N) being reproduced with σ = 0.37 cm-1. The height of the isomerization barrier, the isomerization energy and the dissociation energy were computed using a number of models; our best results are 16 809.4, 5312.8, and 43 729 cm-1, respectively.
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Affiliation(s)
- Vladimir Yu Makhnev
- Institute of Applied Physics, Russian Academy of Science , Ulyanov Street 46, Nizhny Novgorod, Russia 603950
| | - Aleksandra A Kyuberis
- Institute of Applied Physics, Russian Academy of Science , Ulyanov Street 46, Nizhny Novgorod, Russia 603950
| | - Nikolai F Zobov
- Institute of Applied Physics, Russian Academy of Science , Ulyanov Street 46, Nizhny Novgorod, Russia 603950
| | - Lorenzo Lodi
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, United Kingdom
| | - Jonathan Tennyson
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, United Kingdom
| | - Oleg L Polyansky
- Institute of Applied Physics, Russian Academy of Science , Ulyanov Street 46, Nizhny Novgorod, Russia 603950.,Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, United Kingdom
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Abstract
Quantum mechanics builds large-scale graphs (networks): the vertices are the discrete energy levels the quantum system possesses, and the edges are the (quantum-mechanically allowed) transitions. Parts of the complete quantum mechanical networks can be probed experimentally via high-resolution, energy-resolved spectroscopic techniques. The complete rovibronic line list information for a given molecule can only be obtained through sophisticated quantum-chemical computations. Experiments as well as computations yield what we call spectroscopic networks (SN). First-principles SNs of even small, three to five atomic molecules can be huge, qualifying for the big data description. Besides helping to interpret high-resolution spectra, the network-theoretical view offers several ideas for improving the accuracy and robustness of the increasingly important information systems containing line-by-line spectroscopic data. For example, the smallest number of measurements necessary to perform to obtain the complete list of energy levels is given by the minimum-weight spanning tree of the SN and network clustering studies may call attention to "weakest links" of a spectroscopic database. A present-day application of spectroscopic networks is within the MARVEL (Measured Active Rotational-Vibrational Energy Levels) approach, whereby the transitions information on a measured SN is turned into experimental energy levels via a weighted linear least-squares refinement. MARVEL has been used successfully for 15 molecules and allowed to validate most of the transitions measured and come up with energy levels with well-defined and realistic uncertainties. Accurate knowledge of the energy levels with computed transition intensities allows the realistic prediction of spectra under many different circumstances, e.g., for widely different temperatures. Detailed knowledge of the energy level structure of a molecule coming from a MARVEL analysis is important for a considerable number of modeling efforts in chemistry, physics, and engineering.
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Affiliation(s)
- Attila G Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös Loránd University , P.O. Box 32, H-1518 Budapest 112, Hungary.,MTA-ELTE Complex Chemical Systems Research Group , Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Tibor Furtenbacher
- MTA-ELTE Complex Chemical Systems Research Group , Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Péter Árendás
- MTA-ELTE Complex Chemical Systems Research Group , Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary.,Department of Algebra and Number Theory, Institute of Mathematics, Eötvös Loránd University , P.O. Box 120, H-1518 Budapest 112, Hungary
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Mellau GC, Kyuberis AA, Polyansky OL, Zobov N, Field RW. Saddle point localization of molecular wavefunctions. Sci Rep 2016; 6:33068. [PMID: 27629262 PMCID: PMC5024097 DOI: 10.1038/srep33068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/21/2016] [Indexed: 12/13/2022] Open
Abstract
The quantum mechanical description of isomerization is based on bound eigenstates of the molecular potential energy surface. For the near-minimum regions there is a textbook-based relationship between the potential and eigenenergies. Here we show how the saddle point region that connects the two minima is encoded in the eigenstates of the model quartic potential and in the energy levels of the [H, C, N] potential energy surface. We model the spacing of the eigenenergies with the energy dependent classical oscillation frequency decreasing to zero at the saddle point. The eigenstates with the smallest spacing are localized at the saddle point. The analysis of the HCN ↔ HNC isomerization states shows that the eigenstates with small energy spacing relative to the effective (v1, v3, ℓ) bending potentials are highly localized in the bending coordinate at the transition state. These spectroscopically detectable states represent a chemical marker of the transition state in the eigenenergy spectrum. The method developed here provides a basis for modeling characteristic patterns in the eigenenergy spectrum of bound states.
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Affiliation(s)
- Georg Ch. Mellau
- Physikalisch-Chemisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
| | - Alexandra A. Kyuberis
- Institute of Applied Physics, Russian Academy of Science, 46 Uljanov Street, Nizhny Novgorod, Russia
| | - Oleg L. Polyansky
- Institute of Applied Physics, Russian Academy of Science, 46 Uljanov Street, Nizhny Novgorod, Russia
- Department of Physics and Astronomy, University College London, Gower St, London, UK
| | - Nikolai Zobov
- Institute of Applied Physics, Russian Academy of Science, 46 Uljanov Street, Nizhny Novgorod, Russia
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Furtenbacher T, Árendás P, Mellau G, Császár AG. Simple molecules as complex systems. Sci Rep 2014; 4:4654. [PMID: 24722221 PMCID: PMC3983599 DOI: 10.1038/srep04654] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/27/2014] [Indexed: 11/08/2022] Open
Abstract
For individual molecules quantum mechanics (QM) offers a simple, natural and elegant way to build large-scale complex networks: quantized energy levels are the nodes, allowed transitions among the levels are the links, and transition intensities supply the weights. QM networks are intrinsic properties of molecules and they are characterized experimentally via spectroscopy; thus, realizations of QM networks are called spectroscopic networks (SN). As demonstrated for the rovibrational states of H2(16)O, the molecule governing the greenhouse effect on earth through hundreds of millions of its spectroscopic transitions (links), both the measured and first-principles computed one-photon absorption SNs containing experimentally accessible transitions appear to have heavy-tailed degree distributions. The proposed novel view of high-resolution spectroscopy and the observed degree distributions have important implications: appearance of a core of highly interconnected hubs among the nodes, a generally disassortative connection preference, considerable robustness and error tolerance, and an "ultra-small-world" property. The network-theoretical view of spectroscopy offers a data reduction facility via a minimum-weight spanning tree approach, which can assist high-resolution spectroscopists to improve the efficiency of the assignment of their measured spectra.
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Affiliation(s)
- Tibor Furtenbacher
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary
- MTA-ELTE Research Group on Complex Chemical Systems, H-1518 Budapest 112P.O. Box 32, Hungary
| | - Péter Árendás
- MTA-ELTE Research Group on Complex Chemical Systems, H-1518 Budapest 112P.O. Box 32, Hungary
- Department of Algebra and Number Theory, Institute of Mathematics, Eötvös Loránd University, H-1518 Budapest 112P.O. Box 120, Hungary
| | - Georg Mellau
- Physikalisch-Chemisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Attila G. Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary
- MTA-ELTE Research Group on Complex Chemical Systems, H-1518 Budapest 112P.O. Box 32, Hungary
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Fortenberry RC, Crawford TD, Lee TJ. Vibrational frequencies and spectroscopic constants for 1 3A' HNC and 1 3A' HOC+ from high-accuracy quartic force fields. J Phys Chem A 2013; 117:11339-45. [PMID: 24102307 DOI: 10.1021/jp408750h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The spectroscopic constants and vibrational frequencies for the 1 (3)A' states of HNC, DNC, HOC(+), and DOC(+) are computed and discussed in this work. The reliable CcCR quartic force field based on high-level coupled cluster ab initio quantum chemical computations is exclusively utilized to provide the anharmonic potential. Then, second-order vibrational perturbation theory and vibrational configuration interaction methods are employed to treat the nuclear Schrödinger equation. Second-order perturbation theory is also employed to provide spectroscopic data for all molecules examined. The relationship between these molecules and the corresponding 1 (3)A' HCN and HCO(+) isomers is further developed here. These data are applicable to laboratory studies involving formation of HNC and HOC(+) as well as astronomical observations of chemically active astrophysical environments.
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Affiliation(s)
- Ryan C Fortenberry
- Department of Chemistry, Georgia Southern University , Statesboro, Georgia 30460, United States
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Larese D, Pérez-Bernal F, Iachello F. Signatures of quantum phase transitions and excited state quantum phase transitions in the vibrational bending dynamics of triatomic molecules. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.08.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Mellau GC. Complete experimental rovibrational eigenenergies of HCN up to 6880 cm−1 above the ground state. J Chem Phys 2011; 134:234303. [DOI: 10.1063/1.3598942] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Mellau GC. Rovibrational eigenenergy structure of the [H,C,N] molecular system. J Chem Phys 2011; 134:194302. [DOI: 10.1063/1.3590026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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