1
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Mondal S, Bravaya KB. Complex potential energy surfaces with projected CAP technique: Vibrational excitation of N2. J Chem Phys 2024; 161:024106. [PMID: 38984953 DOI: 10.1063/5.0212647] [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: 06/12/2024] [Indexed: 07/11/2024] Open
Abstract
The projected complex absorbing potential (CAP) technique is one of the methods that allow one to extend the bound state methods for computing resonances' energies and widths. Here, we explore the accuracy of the potential energy curves generated with different electronic structure theory methods in combination with the projected CAP technique by considering resonant vibrational excitation (RVE) of N2 by electron impact as a model process. We report RVE cross sections computed using the boomerang model with potential energy curves obtained with CAP-based extended multistate complete active space perturbation theory (XMS-CASPT2) and equation of motion coupled-cluster method for electron attachment with single and double substitution (EOM-EA-CCSD) methods. We also compare potential energy curves computed with several electronic structure methods, including XMS-CASPT2, EOM-EA-CCSD, multireference configuration interaction with singles (MR-CIS) and singles and doubles (MR-CISD). A good agreement is observed between the experiment and simulated RVE cross sections obtained with the potential energy curves generated with XMS-CASPT2 and EOM-EA-CCSD methods, thus highlighting the potential of the projected CAP technique combined with accurate electronic structure methods for dynamical simulations of the processes that proceed through metastable electronic states.
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Affiliation(s)
- Soubhik Mondal
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
| | - Ksenia B Bravaya
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
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2
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Sahoo NP, Franke PR, Stanton JF. On the performance of composite schemes in determining equilibrium molecular structures. J Comput Chem 2024; 45:1419-1427. [PMID: 38450778 DOI: 10.1002/jcc.27312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/10/2023] [Accepted: 12/12/2023] [Indexed: 03/08/2024]
Abstract
Determination of equilibrium molecular structures is an essential ingredient in predicting spectroscopic parameters that help in identifying molecular carriers of microwave transitions. Here, the performance of two different ab initio composite approaches for obtaining equilibrium structures, "energy scheme" and "geometry scheme," is explored and compared to semi-experimental equilibrium structures. This study is performed for a set of 11 molecules which includes diatomics, linear triatomics, and a few non-linear molecules. The ab initio calculations were performed using three tiers of composite chemical recipes. The current results show that as the overall rigor of calculation is increased, the semi-experimental and the ab initio numbers agree to within 0.0003 Å for all molecules in the test set. The composite approach based on correcting the potential energy surface (energy scheme) and the one based on correcting the geometry directly (geometry scheme) show excellent agreement with each other. This work represents a step toward development of efficient and highly accurate procedures for computing ab initio equilibrium structures.
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Affiliation(s)
- Nitai P Sahoo
- Department of Chemistry, University of Florida, Gainesvillle, Florida, USA
| | - Peter R Franke
- Department of Chemistry, University of Florida, Gainesvillle, Florida, USA
| | - John F Stanton
- Department of Chemistry, University of Florida, Gainesvillle, Florida, USA
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3
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Behnle S, Richter R, Völkl L, Idzko P, Förstner A, Bozkaya U, Fink RF. Accurate Property Prediction by Second Order Perturbation Theory: The REMP and OO-REMP Hybrids. J Chem Phys 2022; 157:104111. [DOI: 10.1063/5.0105628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The prediction of molecular properties such as equilibrium structures or vibrationalwavenumbers is a routine task in computational chemistry. If very high accuracy is required, however, the use of computationally demanding ab initio wavefunction methods is mandatory. We present property calculations utilizing the REMP and OO-REMP hybrid perturbation theories showing that with the latter approach, very accurate results are obtained at second order in perturbation theory. Specifically, equilibrium structures and harmonic vibrational wavenumbers as well as dipole moments of closed and open shell molecules were calculated and compared to the best available experimental results or very accurate calculations.OO-REMP is capable of predicting bond lengths of small closed and open shell molecules with an accuracy of 0.2 pm and 0.5 pm, respectively, often within the range of experimental uncertainty. Equilibrium harmonic vibrational wavenumbers are predicted with an accuracy better than 20 cm−1 . Dipole moments of small closed and open shell molecules are reproduced with a relative error of less than 3 %. Across all investigated properties it turns out that a 20 %:80 % MP:RE mixing ratio consistently provides the best results. This is in line with our previous findings featuring closed and open shell reaction energies.
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Affiliation(s)
- Stefan Behnle
- Fachbereich II Chemie, Eberhard Karls Universität Tübingen Fachbereich II Chemie, Germany
| | - Robert Richter
- Eberhard Karls Universitat Tubingen Fachbereich II Chemie, Germany
| | - Luca Völkl
- Eberhard Karls Universitat Tubingen Fachbereich II Chemie, Germany
| | - Paul Idzko
- Eberhard Karls Universitat Tubingen Fachbereich II Chemie, Germany
| | - André Förstner
- Eberhard Karls Universitat Tubingen Fachbereich II Chemie, Germany
| | - Uğur Bozkaya
- Department of Chemistry, Hacettepe University, Turkey
| | - Reinhold F Fink
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen Fachbereich II Chemie, Germany
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4
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Zhang C, Cheng L. Atomic Mean-Field Approach within Exact Two-Component Theory Based on the Dirac-Coulomb-Breit Hamiltonian. J Phys Chem A 2022; 126:4537-4553. [PMID: 35763592 DOI: 10.1021/acs.jpca.2c02181] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An extension of the exact two-component theory with atomic mean-field integrals (the X2CAMF scheme) to the treatment of the Breit term together with efficient implementation using an atomic Dirac-Coulomb-Breit Hartree-Fock program is reported. The accuracy of the X2CAMF scheme for treating the contributions from the Breit term to the molecular properties is demonstrated using benchmark calculations of equilibrium bond lengths, harmonic frequencies, and dipole moments for molecules containing elements across the periodic table. Calculations of the properties for molecules containing period four elements aiming at high accuracy as well as for Th- and U-containing molecules are also presented and compared with experimental results to demonstrate the usefulness of the X2CAMF scheme in combination with accurate treatments of electron correlation by the coupled-cluster (CC) methods. The combination of CC methods and the X2CAMF scheme shows potential to extend the accuracy of CC calculations to heavy elements, e.g., to computational heavy-element thermochemistry.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
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5
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Esch BVD, Peters LDM, Sauerland L, Ochsenfeld C. Quantitative Comparison of Experimental and Computed IR-Spectra Extracted from Ab Initio Molecular Dynamics. J Chem Theory Comput 2021; 17:985-995. [PMID: 33512155 DOI: 10.1021/acs.jctc.0c01279] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Experimentally measured infrared spectra are often compared to their computed equivalents. However, the accordance is typically characterized by visual inspection, which is prone to subjective judgment. The primary challenge for a similarity-based analysis is that the artifacts introduced by each approach are very different and, therefore, may require preprocessing steps to determine and correct impeding irregularities. To allow for automated objective assessment, we propose a practical and comprehensive workflow involving scaling factors, a novel baseline correction scheme, and peak smoothing. The resulting spectra can then easily be compared quantitatively using similarity measures, for which we found the Pearson correlation coefficient to be the most suitable. The proposed procedure is then applied to compare the agreement of the experimental infrared spectra from the NIST Chemistry Web book with the calculated spectra using standard harmonic frequency analysis and spectra extracted from ab initio molecular dynamics simulations at different levels of theory. We conclude that the direct, quantitative comparison of calculated and measured IR spectra might become a novel, sophisticated approach to benchmark quantum-chemical methods. In the present benchmark, simulated spectra based on ab initio molecular dynamics show in general better agreement with the experiment than static calculations.
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Affiliation(s)
- Beatriz von der Esch
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstr. 7, D-81377 München, Germany
| | - Laurens D M Peters
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstr. 7, D-81377 München, Germany
| | - Lena Sauerland
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstr. 7, D-81377 München, Germany
| | - Christian Ochsenfeld
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstr. 7, D-81377 München, Germany
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6
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Perera A, Bartlett RJ, Sanders BA, Lotrich VF, Byrd JN. Advanced concepts in electronic structure (ACES) software programs. J Chem Phys 2020; 152:184105. [DOI: 10.1063/5.0002581] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Ajith Perera
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida 32605, USA
| | - Rodney J. Bartlett
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida 32605, USA
| | - Beverly A. Sanders
- Department of Computer and Information Science and Engineering, University of Florida, Gainesville, Florida 32605, USA
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7
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Araújo JP, Alves MD, da Silva RS, Ballester MY. A comparative study of analytic representations of potential energy curves for O2, N2, and SO in their ground electronic states. J Mol Model 2019; 25:198. [DOI: 10.1007/s00894-019-4079-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 05/28/2019] [Indexed: 11/24/2022]
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8
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Kupka T, Buczek A, Broda MA, Gajda Ł, Ignasiak M. Convergence of nuclear magnetic shieldings and one-bond 1 J( 11 B 1 H) indirect spin-spin coupling constants in small boron molecules. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:338-351. [PMID: 29361201 DOI: 10.1002/mrc.4714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/10/2018] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
Self-consistent field Hartree-Fock, density functional theory, and coupled-cluster calculations of the nuclear magnetic shielding constants of BH and BH3 molecules have been conducted to characterize the convergence of individual results obtained with correlation-consistent and polarization-consistent basis sets. The individual 11 B and 1 H NMR parameters were estimated in the complete basis set limit and compared with benchmark results. Only the KT3 density functional accurately reproduced 11 B shielding in BH molecule.
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Affiliation(s)
- Teobald Kupka
- Faculty of Chemistry, University of Opole, 48, Oleska Street, 46-052, Opole, Poland
| | - Aneta Buczek
- Faculty of Chemistry, University of Opole, 48, Oleska Street, 46-052, Opole, Poland
| | - Małgorzata A Broda
- Faculty of Chemistry, University of Opole, 48, Oleska Street, 46-052, Opole, Poland
| | - Łukasz Gajda
- Faculty of Chemistry, University of Opole, 48, Oleska Street, 46-052, Opole, Poland
| | - Monika Ignasiak
- Faculty of Chemistry, University of Opole, 48, Oleska Street, 46-052, Opole, Poland
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9
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Biczysko M, Krupa J, Wierzejewska M. Theoretical studies of atmospheric molecular complexes interacting with NIR to UV light. Faraday Discuss 2018; 212:421-441. [DOI: 10.1039/c8fd00094h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Theoretical structural and spectroscopic data for weakly bonded atmospheric complexes of formaldehyde interacting with Earth’s electromagnetic spectrum.
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Affiliation(s)
- Malgorzata Biczysko
- International Centre for Quantum and Molecular Structures
- Department of Physics
- College of Sciences
- Shanghai University
- Shanghai
| | - Justyna Krupa
- Faculty of Chemistry
- University of Wrocław
- 50-383 Wrocław
- Poland
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10
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Black JA, Knowles PJ. Statistical analysis of activation and reaction energies with quasi-variational coupled-cluster theory. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1400698] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Joshua A. Black
- School of Chemistry, Cardiff University, Cardiff, United Kingdom
| | - Peter J. Knowles
- School of Chemistry, Cardiff University, Cardiff, United Kingdom
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11
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Brehm M, Thomas M. Computing Bulk Phase Raman Optical Activity Spectra from ab initio Molecular Dynamics Simulations. J Phys Chem Lett 2017; 8:3409-3414. [PMID: 28685571 DOI: 10.1021/acs.jpclett.7b01616] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present our novel methodology for computing Raman optical activity (ROA) spectra of liquid systems from ab initio molecular dynamics (AIMD) simulations. The method is built upon the recent developments to obtain magnetic dipole moments from AIMD and to integrate molecular properties by using radical Voronoi tessellation. These techniques are used to calculate optical activity tensors for large and complex periodic bulk phase systems. Only AIMD simulations are required as input, and no time-consuming perturbation theory is involved. The approach relies only on the total electron density in each time step and can readily be combined with a wide range of electronic structure methods. To the best of our knowledge, these are the first computed ROA spectra for a periodic bulk phase system. As an example, the experimental ROA spectrum of liquid (R)-propylene oxide is reproduced very well.
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Affiliation(s)
- Martin Brehm
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Martin Thomas
- Institut für Chemie - Theoretische Chemie, Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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12
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Gronowski M, Eluszkiewicz P, Custer T. Structure and Spectroscopy of C2HNO Isomers. J Phys Chem A 2017; 121:3263-3273. [DOI: 10.1021/acs.jpca.6b12609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marcin Gronowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Piotr Eluszkiewicz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Thomas Custer
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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13
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Cornaton Y, Ringholm M, Louant O, Ruud K. Analytic calculations of anharmonic infrared and Raman vibrational spectra. Phys Chem Chem Phys 2016; 18:4201-15. [PMID: 26784673 PMCID: PMC5063043 DOI: 10.1039/c5cp06657c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022]
Abstract
Using a recently developed recursive scheme for the calculation of high-order geometric derivatives of frequency-dependent molecular properties [Ringholm et al., J. Comp. Chem., 2014, 35, 622], we present the first analytic calculations of anharmonic infrared (IR) and Raman spectra including anharmonicity both in the vibrational frequencies and in the IR and Raman intensities. In the case of anharmonic corrections to the Raman intensities, this involves the calculation of fifth-order energy derivatives-that is, the third-order geometric derivatives of the frequency-dependent polarizability. The approach is applicable to both Hartree-Fock and Kohn-Sham density functional theory. Using generalized vibrational perturbation theory to second order, we have calculated the anharmonic infrared and Raman spectra of the non- and partially deuterated isotopomers of nitromethane, where the inclusion of anharmonic effects introduces combination and overtone bands that are observed in the experimental spectra. For the major features of the spectra, the inclusion of anharmonicities in the calculation of the vibrational frequencies is more important than anharmonic effects in the calculated infrared and Raman intensities. Using methanimine as a trial system, we demonstrate that the analytic approach avoids errors in the calculated spectra that may arise if numerical differentiation schemes are used.
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Affiliation(s)
- Yann Cornaton
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø-The Arctic University of Norway, N-9037 Tromsø, Norway.
| | - Magnus Ringholm
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø-The Arctic University of Norway, N-9037 Tromsø, Norway.
| | - Orian Louant
- Laboratory of Theoretical Chemistry, UCPTS, University of Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium
| | - Kenneth Ruud
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø-The Arctic University of Norway, N-9037 Tromsø, Norway.
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14
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Koput J. Ab Initiospectroscopic characterization of borane, BH, in its X1Σ+ electronic state. J Comput Chem 2015; 36:2219-27. [DOI: 10.1002/jcc.24200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 08/17/2015] [Accepted: 08/18/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Jacek Koput
- Department of Chemistry; Adam Mickiewicz University; Poznań 61-614 Poland
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15
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Burow AM, Bates JE, Furche F, Eshuis H. Analytical First-Order Molecular Properties and Forces within the Adiabatic Connection Random Phase Approximation. J Chem Theory Comput 2013; 10:180-94. [DOI: 10.1021/ct4008553] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Asbjörn M. Burow
- University of California, Irvine, Department of Chemistry, 1102 Natural Sciences II, Irvine, California 92697-2025, United States of America
| | - Jefferson E. Bates
- University of California, Irvine, Department of Chemistry, 1102 Natural Sciences II, Irvine, California 92697-2025, United States of America
| | - Filipp Furche
- University of California, Irvine, Department of Chemistry, 1102 Natural Sciences II, Irvine, California 92697-2025, United States of America
| | - Henk Eshuis
- Montclair State University, Department of Chemistry
and Biochemistry, 1 Normal
Avenue, Montclair, New Jersey 07043, United States of America
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16
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Sous J, Goel P, Nooijen M. Similarity transformed equation of motion coupled cluster theory revisited: a benchmark study of valence excited states. Mol Phys 2013. [DOI: 10.1080/00268976.2013.847216] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Kupka T, Stachów M, Kaminsky J, Sauer SPA. Estimation of isotropic nuclear magnetic shieldings in the CCSD(T) and MP2 complete basis set limit using affordable correlation calculations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2013; 51:482-489. [PMID: 23749459 DOI: 10.1002/mrc.3974] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/12/2013] [Accepted: 05/14/2013] [Indexed: 06/02/2023]
Abstract
A linear correlation between isotropic nuclear magnetic shielding constants for seven model molecules (CH2 O, H2 O, HF, F2 , HCN, SiH4 and H2 S) calculated with 37 methods (34 density functionals, RHF, MP2 and CCSD(T)), with affordable pcS-2 basis set and corresponding complete basis set results, estimated from calculations with the family of polarization-consistent pcS-n basis sets is reported. This dependence was also supported by inspection of profiles of deviation between CBS estimated nuclear shieldings and shieldings obtained with the significantly smaller basis sets pcS-2 and aug-cc-pVTZ-J for the selected set of 37 calculation methods. It was possible to formulate a practical approach of estimating the values of isotropic nuclear magnetic shielding constants at the CCSD(T)/CBS and MP2/CBS levels from affordable CCSD(T)/pcS-2, MP2/pcS-2 and DFT/CBS calculations with pcS-n basis sets. The proposed method leads to a fairly accurate estimation of nuclear magnetic shieldings and considerable saving of computational efforts.
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Affiliation(s)
- Teobald Kupka
- University of Opole, Faculty of Chemistry, 45-052 Opole, Poland.
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18
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Teale AM, Lutnæs OB, Helgaker T, Tozer DJ, Gauss J. Benchmarking density-functional theory calculations of NMR shielding constants and spin-rotation constants using accurate coupled-cluster calculations. J Chem Phys 2013; 138:024111. [PMID: 23320672 DOI: 10.1063/1.4773016] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Accurate sets of benchmark nuclear-magnetic-resonance shielding constants and spin-rotation constants are calculated using coupled-cluster singles-doubles (CCSD) theory and coupled-cluster singles-doubles-perturbative-triples [CCSD(T)] theory, in a variety of basis sets consisting of (rotational) London atomic orbitals. The accuracy of the calculated coupled-cluster constants is established by a careful comparison with experimental data, taking into account zero-point vibrational corrections. Coupled-cluster basis-set convergence is analyzed and extrapolation techniques are employed to estimate basis-set-limit quantities, thereby establishing an accurate benchmark data set. Together with the set provided for rotational g-tensors and magnetizabilities in our previous work [O. B. Lutnæs, A. M. Teale, T. Helgaker, D. J. Tozer, K. Ruud, and J. Gauss, J. Chem. Phys. 131, 144104 (2009)], it provides a substantial source of consistently calculated high-accuracy data on second-order magnetic response properties. The utility of this benchmark data set is demonstrated by examining a wide variety of Kohn-Sham exchange-correlation functionals for the calculation of these properties. None of the existing approximate functionals provide an accuracy competitive with that provided by CCSD or CCSD(T) theory. The need for a careful consideration of vibrational effects is clearly illustrated. Finally, the pure coupled-cluster results are compared with the results of Kohn-Sham calculations constrained to give the same electronic density. Routes to future improvements are discussed in light of this comparison.
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Affiliation(s)
- Andrew M Teale
- Department of Chemistry, Centre for Theoretical and Computational Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway
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19
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Barone V, Biczysko M, Bloino J, Puzzarini C. Accurate structure, thermodynamic and spectroscopic parameters from CC and CC/DFT schemes: the challenge of the conformational equilibrium in glycine. Phys Chem Chem Phys 2013; 15:10094-111. [PMID: 23599122 DOI: 10.1039/c3cp50439e] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structures, relative stabilities, and infrared spectra of the six low-energy conformers of glycine have been characterized using a state-of-the-art quantum-mechanical approach allowing the bond distances, conformational enthalpies and vibrational frequencies to be determined well within the chemical accuracy. Transition state structures governing interconversion among the different energy minima have also been characterized. In detail, the gas-phase thermodynamic properties (at 15 K and 410 K) of the glycine conformers considered have been obtained with a 1 kJ mol(-1) accuracy, and it has been shown that the employment of DFT geometries usually reduces such accuracy by at most 0.1 kJ mol(-1). Regarding molecular structures, the use of two different composite schemes allowed us to further confirm the suitability of a rather cost-effective approach and provide geometrical parameters with an overall accuracy better than 0.002 Å for distances and 1 degree for angles. Thanks to a hybrid CC/DFT approach, the infrared spectra of all conformers considered and of several deuterated isotopologues have been reproduced (when experimental data were available) or predicted with an accuracy of 10 cm(-1). Finally, the joint thermodynamic and spectroscopic investigation allowed us to shed some light on the possible observation of elusive conformers. On the whole, the high accuracy of the computational results allows us to draw a fully consistent interpretation of the available experimental data and to obtain a more complete characterization of the potential energy surface of glycine.
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Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
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20
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Barone V, Biczysko M, Bloino J, Puzzarini C. Characterization of the Elusive Conformers of Glycine from State-of-the-Art Structural, Thermodynamic, and Spectroscopic Computations: Theory Complements Experiment. J Chem Theory Comput 2013; 9:1533-47. [DOI: 10.1021/ct3010672] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, Piazza
dei Cavalieri 7, I-56126 Pisa, Italy
| | - Malgorzata Biczysko
- Center for Nanotechnology Innovation
@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127
Pisa, Italy
| | - Julien Bloino
- Scuola Normale Superiore, Piazza
dei Cavalieri 7, I-56126 Pisa, Italy
- Consiglio Nazionale
delle Ricerche,
Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), UOS
di Pisa, Area della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Cristina Puzzarini
- Dipartimento di Chimica “G.
Ciamician,” Università di Bologna, Via F. Selmi 2, 40126
Bologna, Italy
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21
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Thomas M, Brehm M, Fligg R, Vöhringer P, Kirchner B. Computing vibrational spectra from ab initio molecular dynamics. Phys Chem Chem Phys 2013; 15:6608-22. [DOI: 10.1039/c3cp44302g] [Citation(s) in RCA: 319] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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22
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Cheng L, Stopkowicz S, Stanton JF, Gauss J. The route to high accuracy inab initiocalculations of Cu quadrupole-coupling constants. J Chem Phys 2012; 137:224302. [DOI: 10.1063/1.4767767] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Laury ML, Carlson MJ, Wilson AK. Vibrational frequency scale factors for density functional theory and the polarization consistent basis sets. J Comput Chem 2012; 33:2380-7. [DOI: 10.1002/jcc.23073] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/19/2012] [Accepted: 06/25/2012] [Indexed: 11/09/2022]
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24
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Puzzarini C, Biczysko M, Barone V. Accurate Anharmonic Vibrational Frequencies for Uracil: The Performance of Composite Schemes and Hybrid CC/DFT Model. J Chem Theory Comput 2011; 7:3702-10. [DOI: 10.1021/ct200552m] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | - Malgorzata Biczysko
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro, 12 - 56127 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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25
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Kahn K, Kirtman B, Hagen A, Noga J. Communication: Convergence of anharmonic infrared intensities of hydrogen fluoride in traditional and explicitly correlated coupled cluster calculations. J Chem Phys 2011; 135:131103. [DOI: 10.1063/1.3647566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Kalju Kahn
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Bernard Kirtman
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Alexander Hagen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Jozef Noga
- Faculty of Natural Sciences, Department of Inorganic Chemistry, Comenius University, Mlynská dolina CH2, SK-84215 Bratislava, Slovakia
- Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-84536 Bratislava, Slovakia
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26
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de Lange KM, Lane JR. Explicit correlation and intermolecular interactions: Investigating carbon dioxide complexes with the CCSD(T)-F12 method. J Chem Phys 2011; 134:034301. [DOI: 10.1063/1.3526956] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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29
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Karton A, Martin JML. Performance of W4 theory for spectroscopic constants and electrical properties of small molecules. J Chem Phys 2010; 133:144102. [DOI: 10.1063/1.3489113] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Friedrich J, Coriani S, Helgaker T, Dolg M. Implementation of the incremental scheme for one-electron first-order properties in coupled-cluster theory. J Chem Phys 2010; 131:154102. [PMID: 20568842 DOI: 10.1063/1.3243864] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A fully automated parallelized implementation of the incremental scheme for coupled-cluster singles-and-doubles (CCSD) energies has been extended to treat molecular (unrelaxed) first-order one-electron properties such as the electric dipole and quadrupole moments. The convergence and accuracy of the incremental approach for the dipole and quadrupole moments have been studied for a variety of chemically interesting systems. It is found that the electric dipole moment can be obtained to within 5% and 0.5% accuracy with respect to the exact CCSD value at the third and fourth orders of the expansion, respectively. Furthermore, we find that the incremental expansion of the quadrupole moment converges to the exact result with increasing order of the expansion: the convergence of nonaromatic compounds is fast with errors less than 16 mau and less than 1 mau at third and fourth orders, respectively (1 mau=10(-3)ea(0)(2)); the aromatic compounds converge slowly with maximum absolute deviations of 174 and 72 mau at third and fourth orders, respectively.
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Affiliation(s)
- Joachim Friedrich
- Institute for Theoretical Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany.
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31
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Kahn K, Kirtman B, Noga J, Ten-no S. Anharmonic vibrational analysis of water with traditional and explicitly correlated coupled cluster methods. J Chem Phys 2010; 133:074106. [DOI: 10.1063/1.3464837] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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32
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Lane JR, Kjaergaard HG. XH-stretching overtone transitions calculated using explicitly correlated coupled cluster methods. J Chem Phys 2010; 132:174304. [DOI: 10.1063/1.3408192] [Citation(s) in RCA: 37] [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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33
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Puzzarini C. Extrapolation to the complete basis set limit of structural parameters: comparison of different approaches. J Phys Chem A 2010; 113:14530-5. [PMID: 19799385 DOI: 10.1021/jp9040327] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
For the first time, different procedures for extrapolating structural parameters to the complete basis set limit are compared. More precisely, a well-tested scheme, based on extrapolated gradients, is employed for validating the extrapolation procedure directly applied to geometrical parameters by means of different extrapolation functions. For this purpose, a set of small systems (mostly triatomics), also containing second-row elements, has been chosen.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica G. Ciamician, Università degli Studi di Bologna, Via Selmi 2, I-40126 Bologna, Italy.
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34
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Kupka T. H2O, H2, HF, F2 and F2O nuclear magnetic shielding constants and indirect nuclear spin-spin coupling constants (SSCCs) in the BHandH/pcJ-n and BHandH/XZP Kohn-Sham limits. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2009; 47:959-970. [PMID: 19681101 DOI: 10.1002/mrc.2500] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Good performance of segmented contracted basis sets XZP, where X = D, T, Q and 5, for obtaining H(2)O, H(2), HF, F(2) and F(2)O nuclear isotropic shielding constants in the BHandH Kohn-Sham basis set limit was shown. The results of two- and three-parameter complete basis set limit extrapolation schemes were compared with experimental results, earlier literature data and benchmark ab initio results. Similar convergence patterns of shieldings obtained from calculations using general purpose XZP basis sets and from polarization-consistent basis sets pcS-n and pcJ-n, where n = 0, 1, 2, 3 and 4, designed to accurately predict magnetic properties were observed. On the contrary, the SSCCs were more sensitive to the XZP basis set size and generally less accurate than those estimated using pcJ-n basis set family. The BHandH density functional markedly outperforms B3LYP method in predicting heavy atom shieldings and SSCCs values in the studied systems.
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Affiliation(s)
- Teobald Kupka
- Department of Chemistry, University of Opole, 48, Oleska Street, 45-052 Opole, Poland.
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35
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Wavefunction quality and error estimation of single- and multi-reference coupled-cluster and CI methods: The H4 model system. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.10.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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36
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Hammond JR, de Jong WA, Kowalski K. Coupled-cluster dynamic polarizabilities including triple excitations. J Chem Phys 2008; 128:224102. [DOI: 10.1063/1.2929840] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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37
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Wennmohs F, Neese F. A comparative study of single reference correlation methods of the coupled-pair type. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.07.001] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Michauk C, Gauss J. Perturbative treatment of scalar-relativistic effects in coupled-cluster calculations of equilibrium geometries and harmonic vibrational frequencies using analytic second-derivative techniques. J Chem Phys 2007; 127:044106. [PMID: 17672680 DOI: 10.1063/1.2751161] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An analytic scheme for the computation of scalar-relativistic corrections to nuclear forces is presented. Relativistic corrections are included via a perturbative treatment involving the mass-velocity and the one-electron and two-electron Darwin terms. Such a scheme requires mixed second derivatives of the nonrelativistic energy with respect to the relativistic perturbation and the nuclear coordinates and can be implemented using available second-derivative techniques. Our implementation for Hartree-Fock self-consistent field, second-order Moller-Plesset perturbation theory, as well as the coupled-cluster level is used to investigate the relativistic effects on the geometrical parameters and harmonic vibrational frequencies for a set of molecules containing light elements (HX, X=F, Cl, Br; H2X, X=O, S; HXY, X=O, S and Y=F, Cl, Br). The focus of our calculations is the basis-set dependence of the corresponding relativistic effects, additivity of electron correlation and relativistic effects, and the importance of core correlation on relativistic effects.
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Affiliation(s)
- Christine Michauk
- Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
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39
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Thar J, Hovorka R, Kirchner B. Basis Set Superposition Error along the Free-Energy Surface of the Water Dimer. J Chem Theory Comput 2007; 3:1510-7. [DOI: 10.1021/ct600259x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jens Thar
- Lehrstuhl für Theoretische Chemie, Wilhelm-Ostwald Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnestrasse 2, D-04103 Leipzig, Germany, and Organische Chemie, Kekulé Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
| | - Rainer Hovorka
- Lehrstuhl für Theoretische Chemie, Wilhelm-Ostwald Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnestrasse 2, D-04103 Leipzig, Germany, and Organische Chemie, Kekulé Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
| | - Barbara Kirchner
- Lehrstuhl für Theoretische Chemie, Wilhelm-Ostwald Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnestrasse 2, D-04103 Leipzig, Germany, and Organische Chemie, Kekulé Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
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40
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Koziol L, Winkler M, Houk KN, Venkataramani S, Sander W, Krylov AI. The 1,2,3-Tridehydrobenzene Triradical: 2B or Not 2B? The Answer is 2A! J Phys Chem A 2007; 111:5071-80. [PMID: 17518455 DOI: 10.1021/jp0714522] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The molecular and electronic structure of 1,2,3-tridehydrobenzene was investigated by a variety of computational methods. The two lowest electronic states of the triradical are the (2)B(2) and (2)A(1) doublet states characterized by different interactions of the unpaired electrons. Vertically, the two states are well separated in energy-by 4.9 and 1.4 eV, respectively. However, due to different bonding patterns, their equilibrium structures are very different and, adiabatically, the two states are nearly degenerate. The adiabatic energy gap between the (2)B(2) and (2)A(1) states is estimated to be 0.7-2.1 kcal/mol, in favor of the (2)A(1) state. Harmonic vibrational frequencies and anharmonic corrections were calculated for both states. Comparison with the three experimentally observed IR transitions supports the assignment of the (2)A(1) ground state for the triradical with a weakly bonding distance of 1.67-1.69 A between the meta radical centers.
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Affiliation(s)
- Lucas Koziol
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
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41
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Tew DP, Klopper W, Heckert M, Gauss J. Basis Set Limit CCSD(T) Harmonic Vibrational Frequencies. J Phys Chem A 2007; 111:11242-8. [PMID: 17511434 DOI: 10.1021/jp070851u] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benchmark, frozen-core CCSD(T) equilibrium harmonic vibrational frequencies of 12 closed-shell and five open-shell molecules are computed to within 1 cm-1 of the basis set limit using the explicitly correlated CCSD(T)-R12 method. The convergence of the standard CCSD(T) method with the one-particle basis sets of Dunning and co-workers is examined and found to be slow, with mean and maximum absolute errors of 1.3 and 3.5 cm-1 remaining at the cc-pV6Z level. Finite basis set effects do not appear to introduce systematic errors in equilibrium harmonic frequencies, and mean absolute errors reduce by a factor of 2 for each basis set cardinal number increment. The convergence of individual equilibrium harmonic frequencies is not guaranteed to be monotonic due to the associated shift in the equilibrium structure. The inclusion of computed scalar relativistic effects and previously available corrections for core-valence correlation and higher-order excitations in the cluster operator results in an agreement with experimentally derived harmonic frequencies of 0.1, 0.3, and -0.4 cm-1 for HF, N2, and CO, respectively. F2 continues to present a challenge to computational chemistry with an error of 3.2 cm-1, primarily resulting from the high basis set dependence of the quadruples contribution.
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Affiliation(s)
- David P Tew
- Lehrstuhl für Theoretische Chemie, Institut für Physikalische Chemie, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
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42
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Schofield DP, Lane JR, Kjaergaard HG. Hydrogen bonded OH-stretching vibration in the water dimer. J Phys Chem A 2007; 111:567-72. [PMID: 17249744 DOI: 10.1021/jp063512u] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have calculated the frequencies and intensities of the hydrogen-bonded OH-stretching transitions in the water dimer complex. The potential-energy curve and dipole-moment function are calculated ab initio at the coupled cluster with singles, doubles, and perturbative triples level of theory with correlation-consistent Dunning basis sets. The vibrational frequencies and wavefunctions are found from a numerical solution to a one-dimensional Schrödinger equation. The corresponding transition intensities are found from numerical integration of these vibrational wavefunctions with the ab initio calculated dipole moment function. We investigate the effect of counterpoise correcting both the potential-energy surface and dipole-moment function. We find that the effect of using a numeric potential is significant for higher overtones and that inclusion of a counterpoise correction for basis set superposition error is important.
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Affiliation(s)
- Daniel P Schofield
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand
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43
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Cortez MH, Brinkmann NR, Polik WF, Taylor PR, Bomble YJ, Stanton JF. Factors Contributing to the Accuracy of Harmonic Force Field Calculations for Water. J Chem Theory Comput 2007; 3:1267-74. [DOI: 10.1021/ct600347e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael H. Cortez
- Department of Chemistry, Hope College, Holland, Michigan 49423, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, and Institute for Theoretical Chemistry, Departments of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
| | - Nicole R. Brinkmann
- Department of Chemistry, Hope College, Holland, Michigan 49423, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, and Institute for Theoretical Chemistry, Departments of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
| | - William F. Polik
- Department of Chemistry, Hope College, Holland, Michigan 49423, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, and Institute for Theoretical Chemistry, Departments of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
| | - Peter R. Taylor
- Department of Chemistry, Hope College, Holland, Michigan 49423, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, and Institute for Theoretical Chemistry, Departments of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
| | - Yannick J. Bomble
- Department of Chemistry, Hope College, Holland, Michigan 49423, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, and Institute for Theoretical Chemistry, Departments of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
| | - John F. Stanton
- Department of Chemistry, Hope College, Holland, Michigan 49423, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, and Institute for Theoretical Chemistry, Departments of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
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44
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Benoit DM. Efficient correlation-corrected vibrational self-consistent field computation of OH-stretch frequencies using a low-scaling algorithm. J Chem Phys 2006; 125:244110. [PMID: 17199343 DOI: 10.1063/1.2423006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The authors present a new computational scheme to perform accurate and fast direct correlation-corrected vibrational self-consistent field (CC-VSCF) computations for a selected number of vibrational modes, which is aimed at predicting a few vibrations in large molecular systems. The method is based on a systematic selection of vibrational mode-mode coupling terms, leading to the direct ab initio construction of a sparse potential energy surface. The computational scaling of the CC-VSCF computation on the generated surface is then further reduced by using a screening procedure for the correlation-correction contributions. The proposed method is applied to the computation of the OH-stretch frequency of five aliphatic alcohols. The authors investigate the influence of different pseudopotential and all-electron basis sets on the quality of the correlated potential energy surfaces computed and on the OH-stretch frequencies calculated for each surface. With the help of these test systems, the authors show that their method offers a computational scaling that is two orders of magnitude lower than a standard CC-VSCF method and that it is of equal accuracy.
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Affiliation(s)
- David M Benoit
- Nachwuchsgruppe Theorie-SFB 569, Albert-Einstein-Allee 11, University of Ulm, D-89081 Ulm, Germany.
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45
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Bartlett RJ, Musiał M. Addition by subtraction in coupled-cluster theory: A reconsideration of the CC and CI interface and the nCC hierarchy. J Chem Phys 2006; 125:204105. [PMID: 17144688 DOI: 10.1063/1.2387952] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The nCC hierarchy of coupled-cluster approximations, where n guarantees exactness for n electrons and all products of n electrons are derived and applied to several illustrative problems. The condition of exactness for n=2 defines nCCSD=2CC, with nCCSDT=3CC and nCCSDTQ=4CC being exact for three and four electrons. To achieve this, the minimum number of diagrams is evaluated, which is less than in the corresponding CC model. For all practical purposes, nCC is also the proper definition of a size-extensive CI. 2CC is also an orbitally invariant coupled electron pair approximation. The numerical results of nCC are close to those for the full CC variant, and in some cases are closer to the full CI reference result. As 2CC is exact for separated electron pairs, it is the natural zeroth-order approximation for the correlation problem in molecules with other effects introduced as these units start to interact. The nCC hierarchy of approximations has all the attractive features of CC including its size extensivity, orbital invariance, and orbital insensitivity, but in a conceptually appealing form suited to bond breaking, while being computationally less demanding. Excited states from the equation of motion (EOM-2CC) are also reported, which show results frequently approaching those of EOM-CCSDT.
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Affiliation(s)
- Rodney J Bartlett
- Quantum Theory Project, Department of Chemistry and Department of Physics, University of Florida, Gainesville, FL 32611, USA
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46
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Himmel HJ, Reiher M. Intrinsische Stickstoff-Aktivierung an “nackten” Metallatomen. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200502892] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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47
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Abstract
There is ongoing interest in metal complexes which bind dinitrogen and facilitate either its reduction or oxidation under mild conditions. In nature, the enzyme nitrogenase catalyzes this process, and dinitrogen fixation occurs under mild and ambient conditions at a metal-sulfur cluster in the center of the MoFe protein, but the mechanism of this process remains largely unknown. In the last few years, new important discoveries have been made in this field. In this review are discussed recent findings on the interaction of N(2) with metal atoms and metal-atom dimers from all groups of the periodic table as provided by gas-phase as well as matrix-isolation experiments. Intrinsic dinitrogen activation at such bare metal atoms is then related to corresponding processes at complexes, clusters, and surfaces.
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Affiliation(s)
- Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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48
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Babikov D, Mozhayskiy VA, Krylov AI. The photoelectron spectrum of elusive cyclic-N3 and characterization of the potential energy surface and vibrational states of the ion. J Chem Phys 2006; 125:084306. [PMID: 16965011 DOI: 10.1063/1.2335437] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A potential energy surface is constructed for the ground X (1)A(1) electronic state of cyclic-N(3) (+) based on three-dimensional spline interpolation of ab initio points. The vibrational states of this molecular ion are calculated in the range up to 14 500 cm(-1) using hyperspherical coordinates and the coupled-channel (sector-adiabatic) approach. All the vibrational states are analyzed and assigned. The Franck-Condon overlaps of these states with the vibrational states of the neutral are calculated to predict the photoelectron spectrum of cyclic-N(3). Peak intensities are governed by the nodal structure of the vibrational wave functions and reflect the large geometric phase effect predicted for cyclic-N(3). Experimental validation may shed light on the existence of this elusive molecule and confirm the magnitude of the geometric phase effect.
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Affiliation(s)
- Dmitri Babikov
- Chemistry Department, Marquette University, Milwaukee, WI 53201-1881, USA.
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49
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Steele RP, DiStasio RA, Shao Y, Kong J, Head-Gordon M. Dual-basis second-order Møller-Plesset perturbation theory: A reduced-cost reference for correlation calculations. J Chem Phys 2006; 125:074108. [PMID: 16942323 DOI: 10.1063/1.2234371] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The resolution-of-the-identity (RI) approximation has placed the onus of the cost of a second-order Moller-Plesset (MP2) calculation on the underlying self-consistent field (SCF) calculation for many moderately sized molecules. A dual-basis approach to the SCF calculation, based on previous methods demonstrated for density functional theory, is combined with RI-MP2 calculations, and small basis subsets for cc-pVTZ, cc-pVQZ, and 6-311++G(3df,3pd) are presented. These subsets provide time savings of greater than 90%, with negligible errors in absolute and relative energies, compared to the associated full-basis counterpart. The method is tested with a series of rotational barriers, relative conformational energies of alanine tetrapeptides, as well as the full G3/99 molecular set. RI-MP2 calculations on alanine octapeptides (40 heavy atoms, 3460 basis functions), using cc-pVQZ, are presented. Results improve upon previous methods that diagonalize the virtual space separately.
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Affiliation(s)
- Ryan P Steele
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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50
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Sinnokrot MO, Sherrill CD. High-Accuracy Quantum Mechanical Studies of π−π Interactions in Benzene Dimers. J Phys Chem A 2006; 110:10656-68. [PMID: 16970354 DOI: 10.1021/jp0610416] [Citation(s) in RCA: 588] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although supramolecular chemistry and noncovalent interactions are playing an increasingly important role in modern chemical research, a detailed understanding of prototype noncovalent interactions remains lacking. In particular, pi-pi interactions, which are ubiquitous in biological systems, are not fully understood in terms of their strength, geometrical dependence, substituent effects, or fundamental physical nature. However, state-of-the-art quantum chemical methods are beginning to provide answers to these questions. Coupled-cluster theory through perturbative triple excitations in conjunction with large basis sets and extrapolations to the complete basis set limit have provided definitive results for the binding energy of several configurations of the benzene dimer, and benchmark-quality ab initio potential curves are being used to calibrate new density functional and force-field models for pi-pi interactions. Studies of substituted benzene dimers indicate flaws in the conventional wisdom about substituent effects in pi-pi interactions. Three-body and four-body interactions in benzene clusters have also been examined.
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Affiliation(s)
- Mutasem Omar Sinnokrot
- Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
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