1001
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Dracínský M, Kaminský J, Bour P. Relative importance of first and second derivatives of nuclear magnetic resonance chemical shifts and spin-spin coupling constants for vibrational averaging. J Chem Phys 2009; 130:094106. [PMID: 19275395 DOI: 10.1063/1.3081317] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Relative importance of anharmonic corrections to molecular vibrational energies, nuclear magnetic resonance (NMR) chemical shifts, and J-coupling constants was assessed for a model set of methane derivatives, differently charged alanine forms, and sugar models. Molecular quartic force fields and NMR parameter derivatives were obtained quantum mechanically by a numerical differentiation. In most cases the harmonic vibrational function combined with the property second derivatives provided the largest correction of the equilibrium values, while anharmonic corrections (third and fourth energy derivatives) were found less important. The most computationally expensive off-diagonal quartic energy derivatives involving four different coordinates provided a negligible contribution. The vibrational corrections of NMR shifts were small and yielded a convincing improvement only for very accurate wave function calculations. For the indirect spin-spin coupling constants the averaging significantly improved already the equilibrium values obtained at the density functional theory level. Both first and complete second shielding derivatives were found important for the shift corrections, while for the J-coupling constants the vibrational parts were dominated by the diagonal second derivatives. The vibrational corrections were also applied to some isotopic effects, where the corrected values reasonably well reproduced the experiment, but only if a full second-order expansion of the NMR parameters was included. Contributions of individual vibrational modes for the averaging are discussed. Similar behavior was found for the methane derivatives, and for the larger and polar molecules. The vibrational averaging thus facilitates interpretation of previous experimental results and suggests that it can make future molecular structural studies more reliable. Because of the lengthy numerical differentiation required to compute the NMR parameter derivatives their analytical implementation in future quantum chemistry packages is desirable.
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Affiliation(s)
- Martin Dracínský
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo namesti 2, 166 10 Prague, Czech Republic.
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1002
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Calvo F, Parneix P, Basire M. Quantum densities of states of fluxional polyatomic systems from a superposition approximation. J Chem Phys 2009; 130:154101. [DOI: 10.1063/1.3115178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1003
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Gangemi F, Gangemi R, Longhi G, Abbate S. Experimental and ab-initio calculated vcd spectra of the first OH-stretching overtone of (1R)-(-) and (1S)-(+)-endo-BORNEOL. Phys Chem Chem Phys 2009; 11:2683-9. [PMID: 19421526 DOI: 10.1039/b818432a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The near infrared (NIR) absorption and NIR-vibrational circular dichroism (NIR-VCD) spectra of dilute solutions of the two enantiomers of endo-borneol have been measured in the first OH-stretching overtone region (1600-1300 nm). By density functional theory (DFT) we calculate mechanical parameters, i.e. the harmonic mechanical frequency and the anharmonicity constant for the OH stretching, and anharmonic electrical parameters; i.e. the dependence on OH-bond length of atomic polar tensors and atomic axial tensors. We evaluate transition integrals for the calculations of rotational and dipole strengths by Morse anharmonic wavefunctions depending on mechanical harmonic frequencies and mechanical anharmonicity parameters that are calculated ab initio. Experimental and calculated spectra compare quite well and this fact allows us to associate differently signed NIR-VCD features with different conformational states of the OH-bond. Absorption features for the fundamental and for the second overtone of the OH stretching are also compared with experiment.
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Affiliation(s)
- Fabrizio Gangemi
- Dipartimento di Scienze Biomediche e Biotecnologie, Viale Europa 11, 25123, Brescia, Italy
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1004
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Matthews DA, Stanton JF. Quantitative analysis of Fermi resonances by harmonic derivatives of perturbation theory corrections. Mol Phys 2009. [DOI: 10.1080/00268970902769463] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Devin A. Matthews
- a Department of Chemistry and Biochemistry , Institute for Theoretical Chemistry, University of Texas at Austin , Austin, TX 78712, USA
| | - John F. Stanton
- a Department of Chemistry and Biochemistry , Institute for Theoretical Chemistry, University of Texas at Austin , Austin, TX 78712, USA
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1005
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Matito E, Toffoli D, Christiansen O. A hierarchy of potential energy surfaces constructed from energies and energy derivatives calculated on grids. J Chem Phys 2009; 130:134104. [DOI: 10.1063/1.3092921] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1006
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Pouchan C, Carbonniere P. Advantages and Drawbacks of Quantum Mechanical Static and Dynamic Approaches to Modelling Infrared Spectra. CHINESE J CHEM PHYS 2009. [DOI: 10.1088/1674-0068/22/02/123-128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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1007
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Tossell JA. H2CO3(s): a new candidate for CO2 capture and sequestration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:2575-2580. [PMID: 19452919 DOI: 10.1021/es802393s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To reduce the magnitude of anthropogenic global warming it is necessary to remove CO2(g) from the effluent streams of coal-fired power plants and to sequester the CO2 either as a liquid or by reaction with other compounds. A major difficulty in achieving this goal arises from the very weak acidity of CO2(g), causing it to react only incompletely with weak bases, although this weak interaction does provide a means for "stripping" the CO2 from the acid-base complex at high temperatures. Reaction with strong bases like Na0H yields more stable complexes, but massive amounts of chemical reactants would need to be purchased and chemical products like NaHCO3 then stored. However, when gas-phase CO2 reacts with the weak base water (or when bicarbonate reacts with strong acid) the unstable product monomeric "H2CO3" can be formed. The free energy required is about 16 kcal/mol in the gas phase and about 10 kcal/mol in aqueous solution. This energy can be supplied by particle or photon excitation and is only a small fraction ofthe energy released when a mole of CH4 is converted to a mole of CO2. Although this monomeric compound is highly unstable, its oligomers are considerably more stable, due to internal H-bonding, with free energies for the larger oligomers in the gas phase which are about 4 kcal/(mol of H2CO3) lower, only about 6 kcal/mol H2CO3 higher than the gas-phase combination of CO2 and H2O at room temperature. Also, at lower temperature the entropic penalty for the oligomer is less and oligomeric H2CO3 becomes stable around the sublimation temperature of dry ice. This indicates that it may be possible to capture gas-phase CO2 directly, using only cheap and abundant H2O as a reactant, and to store the resulting (H2CO3)n as a oligomeric solid at only moderately cold temperatures. These conclusions are based on quantum computations that accurately reproduce the structures, spectra, and stabilities of H2CO3 oligomers. Methods for producing and characterizing the H2CO3 oligomers are discussed. However, some aspects of the proposed scheme are quite speculative and will require additional investigation. Several important questions need to be answered before the feasibility of this procedure on a planetary scale can be assessed, particularly those involving the vapor pressure curve, heat of sublimation, density, and compressibility of (H2CO3)n.
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Affiliation(s)
- J A Tossell
- Department of Chemistry and Biochemistry, University of Maryland College Park, Maryland 20742, USA.
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1008
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Mielke SL, Truhlar DG. Improved Methods for Feynman Path Integral Calculations of Vibrational−Rotational Free Energies and Application to Isotopic Fractionation of Hydrated Chloride Ions. J Phys Chem A 2009; 113:4817-27. [DOI: 10.1021/jp900834u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven L. Mielke
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
| | - Donald G. Truhlar
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
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1009
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1010
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Biczysko M, Bloino J, Barone V. First principle simulation of vibrationally resolved A2B1←X˜2A1 electronic transition of phenyl radical. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.01.082] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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1011
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Zhu C, Liang KK, Hayashi M, Lin SH. Theoretical treatment of anharmonic effect on molecular absorption, fluorescence spectra, and electron transfer. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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1012
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Gaigeot MP. Alanine polypeptide structural fingerprints at room temperature: what can be gained from non-harmonic Car-Parrinello molecular dynamics simulations. J Phys Chem A 2009; 112:13507-17. [PMID: 19053558 DOI: 10.1021/jp807550j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Structural infrared fingerprints of neutral gas phase alanine peptides of increasing size and complexity (dipeptide, octapeptide, and beta-strand peptide) are characterized through DFT-based Car-Parrinello molecular dynamics simulations. Harmonic and nonharmonic vibrational signatures are calculated from the time correlation of the dipole moment of the gas phase peptide in a direct way (without any approximation) respectively from low temperature (20 K) and room temperature (300 K) molecular dynamics. Our main purpose is to answer the two following questions: (i) Is the direct inclusion of temperature for the calculation of infrared spectra mandatory for the comprehension of the vibrational signatures experimentally recorded at room temperature? (ii) To what extent is the amide I, II, and III domain sensitive enough to the local structure of the peptides, to provide vibrational signatures that can be definitely used to assess the peptide conformation at 300 K?
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Affiliation(s)
- M-P Gaigeot
- LAMBE UMR8587 Laboratoire Analyse et Modelisation pour la Biologie et l'Environnement, Universite d'Evry val d'Essonne, Boulevard F. Mitterrand, Batiment Maupertuis, 91025 Evry, France.
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1013
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Barone V, Bloino J, Biczysko M, Santoro F. Fully Integrated Approach to Compute Vibrationally Resolved Optical Spectra: From Small Molecules to Macrosystems. J Chem Theory Comput 2009; 5:540-54. [PMID: 26610221 DOI: 10.1021/ct8004744] [Citation(s) in RCA: 338] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A general and effective time-independent approach to compute vibrationally resolved electronic spectra from first principles has been integrated into the Gaussian computational chemistry package. This computational tool offers a simple and easy-to-use way to compute theoretical spectra starting from geometry optimization and frequency calculations for each electronic state. It is shown that in such a way it is straightforward to combine calculation of Franck-Condon integrals with any electronic computational model. The given examples illustrate the calculation of absorption and emission spectra, all in the UV-vis region, of various systems from small molecules to large ones, in gas as well as in condensed phases. The computational models applied range from fully quantum mechanical descriptions to discrete/continuum quantum mechanical/molecular mechanical/polarizable continuum models.
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Affiliation(s)
- Vincenzo Barone
- Dipartimento di Chimica "Paolo Corradini" and CR-INSTM Village, Universita di Napoli Federico II, Complesso Univ. Monte S. Angelo, via Cintia, 80126 Napoli, Italy, and Istituto per i Processi Chimico-Fisici, Area della Ricerca-CNR, via G. Moruzzi, 56124 Pisa, Italy
| | - Julien Bloino
- Dipartimento di Chimica "Paolo Corradini" and CR-INSTM Village, Universita di Napoli Federico II, Complesso Univ. Monte S. Angelo, via Cintia, 80126 Napoli, Italy, and Istituto per i Processi Chimico-Fisici, Area della Ricerca-CNR, via G. Moruzzi, 56124 Pisa, Italy
| | - Malgorzata Biczysko
- Dipartimento di Chimica "Paolo Corradini" and CR-INSTM Village, Universita di Napoli Federico II, Complesso Univ. Monte S. Angelo, via Cintia, 80126 Napoli, Italy, and Istituto per i Processi Chimico-Fisici, Area della Ricerca-CNR, via G. Moruzzi, 56124 Pisa, Italy
| | - Fabrizio Santoro
- Dipartimento di Chimica "Paolo Corradini" and CR-INSTM Village, Universita di Napoli Federico II, Complesso Univ. Monte S. Angelo, via Cintia, 80126 Napoli, Italy, and Istituto per i Processi Chimico-Fisici, Area della Ricerca-CNR, via G. Moruzzi, 56124 Pisa, Italy
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1014
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Rauhut G, Knizia G, Werner HJ. Accurate calculation of vibrational frequencies using explicitly correlated coupled-cluster theory. J Chem Phys 2009; 130:054105. [DOI: 10.1063/1.3070236] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1015
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Anomalously strong effect of the ion sign on the thermochemistry of hydrogen bonded aqueous clusters of identical chemical composition. Int J Mol Sci 2009; 10:507-517. [PMID: 19333418 PMCID: PMC2660665 DOI: 10.3390/ijms10020507] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 01/05/2009] [Accepted: 01/07/2009] [Indexed: 12/26/2022] Open
Abstract
The sign preference of hydrogen bonded aqueous ionic clusters X±(H2O)i (n =1–5, X = F; Cl; Br) has been investigated using the Density Functional Theory and ab initio MP2 method. The present study indicates the anomalously large difference in formation free energies between cations and anions of identical chemical composition. The effect of vibrational anharmonicity on stepwise Gibbs free energy changes has been investigated, and possible uncertainties associated with the harmonic treatment of vibrational spectra have been discussed.
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1016
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Reilly AM, Wann DA, Rankin DWH. What makes the huge 31P-31P coupling constants in S(PF2)2 and Se(PF2)2 vary so much with temperature? J Phys Chem A 2009; 113:938-42. [PMID: 19175336 DOI: 10.1021/jp8100078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The enormous temperature dependence of the (2)J(PP) coupling constants in S(PF(2))(2) and Se(PF(2))(2) has been explained by a theoretical investigation of their conformations and NMR coupling constants. In contrast, the coupling in O(PF(2))(2) is almost invariant. Gas electron diffraction data for S(PF(2))(2) have been reinterpreted. The results show that two conformers, with C(s) and C(2v) symmetry, exist for the S and Se compounds. The C(s) and C(2v) conformers have very different (2)J(PP) coupling constants (-12.6 and 395.2 Hz for S(PF(2))(2) at B3LYP/aug-cc-pVQZ) and thermal interconversion of these conformers explains the experimental behavior.
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Affiliation(s)
- Anthony M Reilly
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
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1017
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Puzzarini C, Barone V. Toward spectroscopic accuracy for organic free radicals: Molecular structure, vibrational spectrum, and magnetic properties of F(2)NO. J Chem Phys 2009; 129:084306. [PMID: 19044822 DOI: 10.1063/1.2969820] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The structure, harmonic frequencies, and hyperfine couplings of F(2)NO have been computed by the coupled cluster ansatz using a hierarchical series of basis sets and, in some cases, extrapolation procedures to reach the complete basis set limit. Methods rooted into the density functional theory have been used to estimate anharmonic and environmental effects. The remarkable agreement with experimental hyperfine coupling constants and most of vibrational frequencies confirms the reliability of the computational approach and suggests that one of the observed frequencies probably refers to a different species.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica G. Ciamician, Università di Bologna, Via F. Selmi 2, I-40126 Bologna, Italy.
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1018
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Aldridge S, Downs AJ, Tang CY, Parsons S, Clarke MC, Johnstone RDL, Robertson HE, Rankin DWH, Wann DA. Structures and Aggregation of the Methylamine−Borane Molecules, MenH3−nN·BH3 (n = 1−3), Studied by X-ray Diffraction, Gas-Phase Electron Diffraction, and Quantum Chemical Calculations. J Am Chem Soc 2009; 131:2231-43. [PMID: 19170515 DOI: 10.1021/ja807545p] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Simon Aldridge
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Anthony J. Downs
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Christina Y. Tang
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Simon Parsons
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Michael C. Clarke
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Russell D. L. Johnstone
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Heather E. Robertson
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - David W. H. Rankin
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Derek A. Wann
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., and School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
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1019
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Abbate S, Castiglioni E, Gangemi F, Gangemi R, Longhi G. NIR-VCD, vibrational circular dichroism in the near-infrared: Experiments, theory and calculations. Chirality 2009; 21 Suppl 1:E242-52. [DOI: 10.1002/chir.20805] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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1020
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Torrent-Sucarrat M, Anglada JM, Luis JM. Role of vibrational anharmonicity in atmospheric radical hydrogen-bonded complexes. Phys Chem Chem Phys 2009; 11:6377-88. [DOI: 10.1039/b904736k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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1021
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Ramasami P. Structures and vibrational spectroscopic parameters of selenoxopropanedinitrile and selenoxosilanedicarbonitrile: Theoretical study based on density functional theory method. HETEROATOM CHEMISTRY 2009. [DOI: 10.1002/hc.20535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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1022
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1023
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Carbonniere P, Dargelos A, Ciofini I, Adamo C, Pouchan C. Vibrational analysis of glycine radical: a comparative ab initio static and dynamic study. Phys Chem Chem Phys 2009; 11:4375-84. [DOI: 10.1039/b817468g] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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1024
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Puzzarini C, Barone V. The role of accurate quantum mechanical computations in the assignment of vibrational spectra for unstable free radicals: H2CN and F2CN as test cases. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2008.11.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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1025
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Khater B, Guillemin JC, Benidar A, Bégué D, Pouchan C. Vinylphosphine-borane: Synthesis, gas phase infrared spectroscopy, and quantum chemical vibrational calculations. J Chem Phys 2008; 129:224308. [DOI: 10.1063/1.3035902] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1026
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Zierkiewicz W, Komorowski L, Michalska D, Cerny J, Hobza P. The Amino Group in Adenine: MP2 and CCSD(T) Complete Basis Set Limit Calculations of the Planarization Barrier and DFT/B3LYP Study of the Anharmonic Frequencies of Adenine. J Phys Chem B 2008; 112:16734-40. [DOI: 10.1021/jp8058118] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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1027
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Barone V, Cimino P. Validation of the B3LYP/N07D and PBE0/N07D Computational Models for the Calculation of Electronic g-Tensors. J Chem Theory Comput 2008; 5:192-9. [DOI: 10.1021/ct800279g] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Vincenzo Barone
- Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche, Via G. Moruzzi 1, I-56124 Pisa, Italy, and Dipartimento di Scienze Farmaceutiche, Università di Salerno, via Ponte don Melillo, I-84084 Fisciano (Sa), Italy
| | - Paola Cimino
- Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche, Via G. Moruzzi 1, I-56124 Pisa, Italy, and Dipartimento di Scienze Farmaceutiche, Università di Salerno, via Ponte don Melillo, I-84084 Fisciano (Sa), Italy
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1028
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1029
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Douady J, Calvo F, Spiegelman F. Structure, stability, and infrared spectroscopy of (H2O)nNH4+ clusters: A theoretical study at zero and finite temperature. J Chem Phys 2008; 129:154305. [DOI: 10.1063/1.2987304] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1030
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Ramasami P. DFT study of the molecular structures, infrared and Raman spectra of 1,5-dichloropenta-1,4-diyn-3-one, 1,5-dibromopenta- 1,4-diyn-3-one, 1,5-diiodopenta-1,4-diyn-3-one, their sulfur, and selenium analogues. J Sulphur Chem 2008. [DOI: 10.1080/17415990801959060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Ponnadurai Ramasami
- a Department of Chemistry, Faculty of Science , University of Mauritius , Réduit, Mauritius
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1031
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Puzzarini C, Barone V. Assessment of a computational strategy approaching spectroscopic accuracy for structure, magnetic properties and vibrational frequencies of organic free radicals: the F(2)CN and F(2)BO case. Phys Chem Chem Phys 2008; 10:6991-7. [PMID: 19030595 DOI: 10.1039/b813145g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular structure, vibrational frequencies, and hyperfine couplings of F(2)CN and F(2)BO have been computed at the coupled cluster level in conjunction with hierarchical series of correlation consistent basis sets. For geometrical and hyperfine parameters, extrapolation to the complete basis set limit and inclusion of core correlation effects have been considered. While a remarkable agreement with most of vibrational frequencies supports the reliability of the computational approach followed, experimental geometries cannot be used for validation purposes due to their limited accuracy. In view of previous experience with related radicals, the computed hyperfine coupling constants as well as molecular structures are expected to be very reliable and accurate.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via F. Selmi 2, I-40126, Bologna, Italy.
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1032
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Dobrowolski JC, Jamróz MH, Kołos R, Rode JE, Sadlej J. IR Low-Temperature Matrix and ab Initio Study on β-Alanine Conformers. Chemphyschem 2008; 9:2042-51. [DOI: 10.1002/cphc.200800383] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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1033
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Carbonnière P, Pouchan C. Vibrational spectra for P4O6 and P4O10 systems: Theoretical study from DFT quartic potential and mixed perturbation-variation method. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.07.056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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1034
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Bloino J, Biczysko M, Crescenzi O, Barone V. Integrated computational approach to vibrationally resolved electronic spectra: anisole as a test case. J Chem Phys 2008; 128:244105. [PMID: 18601315 DOI: 10.1063/1.2943140] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A new general and effective procedure to compute Franck-Condon spectra from first principles is exploited to elucidate the subtle features of the vibrationally resolved optical spectra of anisole. Methods based on the density functional theory and its time-dependent extension for electronic excited states [B3LYP6-311+G(d,p) and TD-B3LYP6-311+G(d,p)] have been applied to geometry optimizations and harmonic frequency calculations. Perturbative anharmonic frequencies [J. Chem. Phys. 122, 014108 (2005)] have been calculated for the ground state, and the Duschinsky matrix elements have been used to evaluate the corresponding anharmonic corrections for the first excited electronic state. The relative energetics of both electronic states has been refined by single point calculations at the coupled clusters (CC) level with the aug-cc-pVDZ basis set. Theoretical spectra have been evaluated using a new optimized implementation for the effective computation of Franck-Condon factors. The remarkable agreement between theoretical and experimental spectra allowed for revision of some assignments of fundamental vibrations in the S(1) state of anisole.
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Affiliation(s)
- Julien Bloino
- Dipartimento di Chimica "Paolo Corradini" and CR-INSTM Village, Universita di Napoli Federico II, Complesso Univ. Monte S. Angelo, via Cintia, 80126 Napoli, Italy
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1035
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Basire M, Parneix P, Calvo F. Quantum anharmonic densities of states using the Wang–Landau method. J Chem Phys 2008; 129:081101. [DOI: 10.1063/1.2965905] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1036
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Watanabe Y, Maeda S, Ohno K. Intramolecular vibrational frequencies of water clusters (H2O)n (n=2–5): Anharmonic analyses using potential functions based on the scaled hypersphere search method. J Chem Phys 2008; 129:074315. [DOI: 10.1063/1.2973605] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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1037
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Pichierri F. Molecular structure of the octatetranyl anion, C8H-: a computational study. J Phys Chem A 2008; 112:7717-22. [PMID: 18666765 DOI: 10.1021/jp710297g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The equilibrium molecular structure of the octatetranyl anion, C8H(-), which has been recently detected in two astronomical environments, is investigated with the aid of both ab initio post-Hartree-Fock and density functional theory (DFT) calculations. The model chemistry adopted in this study was selected after a series of benchmark calculations performed on molecular acetylene for which accurate gas-phase structural data are available. Geometry optimizations performed at the CCSD/6-311+G(2d,p), QCISD/6-311+G(2d,p), and MP4(SDQ)/6-311+G(2d,p) levels of theory yield for C8H(-) an interesting polyyne-type structure that defies the chemical formula displaying a simple alternation of triple and single carbon-carbon bonds, [:C[triple bond]C-C[triple bond]C-C[triple bond]C-C[triple bond]CH](1-). In the optimized geometry of C8H(-), as one proceeds from the naked carbon atom on one side of the chain to the CH unit on the opposite side of the chain, the short (formally triple) carbon-carbon bonds decrease in length from 1.255 to 1.213 A whereas the long (formally single) carbon-carbon bonds increase (albeit only slightly) in length from 1.362 to 1.378 A (CCSD results). In striking contrast, both MP2 and DFT (B3LYP and PBE0) calculations fail in reproducing the pattern of the carbon-carbon bond lengths obtained with the CCSD, QCISD, and MP4 methods. The structures of three shorter n-even chains, C(n)H(-) (n = 2, 4, and 6), along with those of four n-odd compounds (n = 3, 5, 7, and 9) are also investigated at the CCSD/6-311+G(2d,p) level of theory.
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Affiliation(s)
- Fabio Pichierri
- G-COE Laboratory, Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-07, Sendai 980-8579, Japan.
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1038
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Bowman JM, Carrington T, Meyer HD. Variational quantum approaches for computing vibrational energies of polyatomic molecules. Mol Phys 2008. [DOI: 10.1080/00268970802258609] [Citation(s) in RCA: 303] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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1039
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Filippov OA, Tsupreva VN, Epstein LM, Lledos A, Shubina ES. Intermolecular HH vibrations of dihydrogen bonded complexes H3EH(-)...HOR in the low-frequency region: theory and IR spectra. J Phys Chem A 2008; 112:8198-204. [PMID: 18698750 DOI: 10.1021/jp804303j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The results of DFT calculations of harmonic and anharmonic frequencies of the dihydrogen bonded (DHB) complexes H 3EH (-)...HOR (E = B, Al, Ga and HOR = CH 3OH, CF 3CH 2OH) in gas phase and in low polar medium (by CPCM model) in comparison with the partners are presented. Normal coordinate analysis of the low-frequency modes was carried out to assign the new vibrations induced by DHB formation by the potential energy distribution values. Among them, the intermolecular H...H stretching vibrations only have individual modes. The influence of central atom mass and isotope and the strength of the proton donor effects were determined. The systems convenient for IR studies were chosen from the calculation predictions. The spectral investigation was made on the BH 4 (-)/ROH complexes (ROH = CH 2FCH 2OH (MFE), CF 3CH 2OH (TFE), (CF 3) 2CHOH (HFIP)). The results of temperature dependence, isotope substitution, and influence of the proton-donor strength studies agree with the theoretical conclusions. Combination of experimental and theoretical approaches allowed determining for the first time the intermolecular stretching mode characterizing intrinsic DHB vibrations.
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Affiliation(s)
- Oleg A Filippov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
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1040
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Zaleski-Ejgierd P, Patzschke M, Pyykkö P. Structure and bonding of the MCN molecules, M=Cu,Ag,Au,Rg. J Chem Phys 2008; 128:224303. [DOI: 10.1063/1.2937148] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1041
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Iterative active-space selection for vibrational configuration interaction calculations using a reduced-coupling VSCF basis. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.05.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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1042
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Barone V, Improta R, Rega N. Quantum mechanical computations and spectroscopy: from small rigid molecules in the gas phase to large flexible molecules in solution. Acc Chem Res 2008; 41:605-16. [PMID: 18307319 DOI: 10.1021/ar7002144] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Interpretation of structural properties and dynamic behavior of molecules in solution is of fundamental importance to understand their stability, chemical reactivity, and catalytic action. While information can be gained, in principle, by a variety of spectroscopic techniques, the interpretation of the rich indirect information that can be inferred from the analysis of experimental spectra is seldom straightforward because of the subtle interplay of several different effects, whose specific role is not easy to separate and evaluate. In such a complex scenario, theoretical studies can be very helpful at two different levels: (i) supporting and complementing experimental results to determine the structure of the target molecule starting from its spectral properties; (ii) dissecting and evaluating the role of different effects in determining the observed spectroscopic properties. This is the reason why computational spectroscopy is rapidly evolving from a highly specialized research field into a versatile and widespread tool for the assignment of experimental spectra and their interpretation in terms of chemical physical effects. In such a situation, it becomes important that both computationally and experimentally oriented chemists are aware that new methodological advances and integrated computational strategies are available, providing reliable estimates of fundamental spectral parameters not only for relatively small molecules in the gas phase but also for large and flexible molecules in condensed phases. In this Account, we review the most significant methodological contributions from our research group in this field, and by exploiting some recent results of their application to the computation of IR, UV-vis, NMR, and EPR spectral parameters, we discuss the microscopic mechanisms underlying solvent and vibrational effects on the spectral parameters. After reporting some recent achievements for the study of excited states by first principle quantum mechanical approaches, we focus on the treatment of environmental effects by means of mixed discrete-continuum solvent models and on effective methods for computing vibronic contributions to the spectra. We then discuss some new developments, mainly based on time-dependent approaches, allowing us to go beyond the determination of spectroscopic parameters toward the simulation of line widths and shapes. Although further developments are surely needed to improve the accuracy and effectiveness of several items in the proposed approach, we try to show that the first important steps toward a direct comparison between the results obtained in vitro and those obtained in silico have been made, making easier fruitful crossovers among experiments, computations and theoretical models, which would be decisive for a deeper understanding of the spectral behavior associated with complex systems and processes.
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Affiliation(s)
- Vincenzo Barone
- LSDM and CR-INSTM VILLAGE, Chemistry Department Paolo Corradini, University Federico II, Complesso Universitario Monte S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Roberto Improta
- LSDM and CR-INSTM VILLAGE, Chemistry Department Paolo Corradini, University Federico II, Complesso Universitario Monte S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Nadia Rega
- LSDM and CR-INSTM VILLAGE, Chemistry Department Paolo Corradini, University Federico II, Complesso Universitario Monte S. Angelo, via Cintia, I-80126 Napoli, Italy
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1043
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1044
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Bounouar M, Scheurer C. The impact of approximate VSCF schemes and curvilinear coordinates on the anharmonic vibrational frequencies of formamide and thioformamide. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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1045
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Pele L, Gerber RB. On the number of significant mode-mode anharmonic couplings in vibrational calculations: Correlation-corrected vibrational self-consistent field treatment of di-, tri-, and tetrapeptides. J Chem Phys 2008; 128:165105. [DOI: 10.1063/1.2909558] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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1046
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Seidler P, Hansen MB, Christiansen O. Towards fast computations of correlated vibrational wave functions: Vibrational coupled cluster response excitation energies at the two-mode coupling level. J Chem Phys 2008; 128:154113. [DOI: 10.1063/1.2907860] [Citation(s) in RCA: 41] [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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1047
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Stranges D, O’Keeffe P, Scotti G, Di Santo R, Houston PL. Competing sigmatropic shift rearrangements in excited allyl radicals. J Chem Phys 2008; 128:151101. [DOI: 10.1063/1.2907714] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1048
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Maeda S, Watanabe Y, Ohno K. Finding important anharmonic terms in the sixth-order potential energy function by the scaled hypersphere search method: An application to vibrational analyses of molecules and clusters. J Chem Phys 2008; 128:144111. [DOI: 10.1063/1.2884348] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1049
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Cahoon JF, Sawyer KR, Schlegel JP, Harris CB. Determining transition-state geometries in liquids using 2D-IR. Science 2008; 319:1820-3. [PMID: 18369145 DOI: 10.1126/science.1154041] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Many properties of chemical reactions are determined by the transition state connecting reactant and product, yet it is difficult to directly obtain any information about these short-lived structures in liquids. We show that two-dimensional infrared (2D-IR) spectroscopy can provide direct information about transition states by tracking the transformation of vibrational modes as a molecule crossed a transition state. We successfully monitored a simple chemical reaction, the fluxional rearrangement of Fe(CO)5, in which the exchange of axial and equatorial CO ligands causes an exchange of vibrational energy between the normal modes of the molecule. This energy transfer provides direct evidence regarding the time scale, transition state, and mechanism of the reaction.
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Affiliation(s)
- James F Cahoon
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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1050
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Krasnoshchekov SV, Stepanov NF. Anharmonic Force Fields and Perturbation Theory in the Interpretation of Vibrational Spectra of Polyatomic Molecules. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2008. [DOI: 10.1134/s0036024408040158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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