1
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Nagy PR. State-of-the-art local correlation methods enable affordable gold standard quantum chemistry for up to hundreds of atoms. Chem Sci 2024:d4sc04755a. [PMID: 39246365 PMCID: PMC11376132 DOI: 10.1039/d4sc04755a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 07/30/2024] [Indexed: 09/10/2024] Open
Abstract
In this feature, we review the current capabilities of local electron correlation methods up to the coupled cluster model with single, double, and perturbative triple excitations [CCSD(T)], which is a gold standard in quantum chemistry. The main computational aspects of the local method types are assessed from the perspective of applications, but the focus is kept on how to achieve chemical accuracy (i.e., <1 kcal mol-1 uncertainty), as well as on the broad scope of chemical problems made accessible. The performance of state-of-the-art methods is also compared, including the most employed DLPNO and, in particular, our local natural orbital (LNO) CCSD(T) approach. The high accuracy and efficiency of the LNO method makes chemically accurate CCSD(T) computations accessible for molecules of hundreds of atoms with resources affordable to a broad computational community (days on a single CPU and 10-100 GB of memory). Recent developments in LNO-CCSD(T) enable systematic convergence and robust error estimates even for systems of complicated electronic structure or larger size (up to 1000 atoms). The predictive power of current local CCSD(T) methods, usually at about 1-2 order of magnitude higher cost than hybrid density functional theory (DFT), has become outstanding on the palette of computational chemistry applicable for molecules of practical interest. We also review more than 50 LNO-based and other advanced local-CCSD(T) applications for realistic, large systems across molecular interactions as well as main group, transition metal, bio-, and surface chemistry. The examples show that properly executed local-CCSD(T) can contribute to binding, reaction equilibrium, rate constants, etc. which are able to match measurements within the error estimates. These applications demonstrate that modern, open-access, and broadly affordable local methods, such as LNO-CCSD(T), already enable predictive computations and atomistic insight for complicated, real-life molecular processes in realistic environments.
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Affiliation(s)
- Péter R Nagy
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics Műegyetem rkp. 3. H-1111 Budapest Hungary
- HUN-REN-BME Quantum Chemistry Research Group Műegyetem rkp. 3. H-1111 Budapest Hungary
- MTA-BME Lendület Quantum Chemistry Research Group Műegyetem rkp. 3. H-1111 Budapest Hungary
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2
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Tang Z, Zhu H, Pan Z, Gao J, Zhang J. A many-body energy decomposition analysis (MB-EDA) scheme based on a target state optimization self-consistent field (TSO-SCF) method. Phys Chem Chem Phys 2024; 26:17549-17560. [PMID: 38884195 DOI: 10.1039/d4cp01259c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
In this paper, we combine an energy decomposition analysis (EDA) scheme with many-body expansion (MBE) to develop a MB-EDA method to study the cooperative and anti-cooperative effects in molecular cluster systems. Based on the target state optimization self-consistent field (TSO-SCF) method, the intermolecular interaction energy can be decomposed into five chemically meaningful terms, i.e., electrostatic, exchange, polarization, charge transfer and dispersion interaction energies. MB-EDA can decompose each of these terms in MBE. This MB-EDA has been applied to 3 different cluster systems: water clusters, ionic liquid clusters, and acetonitrile-methane clusters. This reveals that electrostatic, exchange, and dispersion interactions are highly pairwise additive in all systems. In water and ionic liquid clusters, the many-body effects are significant in both polarization and charge transfer interactions, but are cooperative and anti-cooperative, respectively. For acetonitrile-methane clusters, which do not involve hydrogen bonds or charge-charge Coulombic interactions, the many-body effects are quite small. The chemical origins of different many-body effects are deeply analyzed. The MB-EDA method has been implemented in Qbics (https://qbics.info) and can be a useful tool for understanding the many-body behavior in molecular aggregates at the quantum chemical level of theory.
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Affiliation(s)
- Zhen Tang
- Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, People's Republic of China.
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518055, People's Republic of China.
| | - Hong Zhu
- Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, People's Republic of China.
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518055, People's Republic of China.
| | - Zhijun Pan
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518055, People's Republic of China.
| | - Jiali Gao
- Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, People's Republic of China.
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518055, People's Republic of China.
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jun Zhang
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518055, People's Republic of China.
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3
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Türkmen I, Dolg M. Linear Scaling Incremental Scheme for Correlation Energies with Embedding Generated Virtuals. J Chem Theory Comput 2024; 20:3154-3168. [PMID: 38588492 DOI: 10.1021/acs.jctc.3c01377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
A novel incremental scheme is presented including an incremental expansion of the virtual space for the calculation of electron correlation energies, which is compatible with any size-extensive correlation method and scales asymptotically linear for large molecules. The performance is studied for organic molecules, water clusters, and a La(III)-water complex, where the compatibility with pseudopotentials is also examined. The computational requirements are already reduced tremendously for medium-sized water clusters and hydrocarbons with respect to the canonical CCSD as well as the ordinary incremental scheme references. Correlation energies within chemical accuracy have been observed for all studied systems. The novelty of the method is that relatively small virtual spaces are used in combination with tuples of localized occupied spaces. The corresponding orthonormal occupied and virtual orbitals are obtained from QM/QM embedding calculations and can thus be used with standard quantum chemistry codes for correlation calculations. It is presented how relevant virtual spaces are selected and the correlation energies are linked in the new virtual space expansion.
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Affiliation(s)
- Ilyas Türkmen
- Institute for Theoretical Chemistry, University of Cologne, Greinstr. 4, D-50939 Cologne, Germany
| | - Michael Dolg
- Institute for Theoretical Chemistry, University of Cologne, Greinstr. 4, D-50939 Cologne, Germany
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4
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Szabó PB, Csóka J, Kállay M, Nagy PR. Linear-Scaling Local Natural Orbital CCSD(T) Approach for Open-Shell Systems: Algorithms, Benchmarks, and Large-Scale Applications. J Chem Theory Comput 2023; 19:8166-8188. [PMID: 37921429 PMCID: PMC10687875 DOI: 10.1021/acs.jctc.3c00881] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023]
Abstract
The extension of the highly optimized local natural orbital (LNO) coupled cluster (CC) with single-, double-, and perturbative triple excitations [LNO-CCSD(T)] method is presented for high-spin open-shell molecules based on restricted open-shell references. The techniques enabling the outstanding efficiency of the closed-shell LNO-CCSD(T) variant are adopted, including the iteration- and redundancy-free second-order Møller-Plesset and (T) formulations as well as the integral-direct, memory- and disk use-economic, and OpenMP-parallel algorithms. For large molecules, the efficiency of our open-shell LNO-CCSD(T) method approaches that of its closed-shell parent method due to the application of restricted orbital sets for demanding integral transformations and a novel approximation for higher-order long-range spin-polarization effects. The accuracy of open-shell LNO-CCSD(T) is extensively tested for radicals and reactions thereof, ionization processes, as well as spin-state splittings, and transition-metal compounds. At the size range where the canonical CCSD(T) reference is accessible (up to 20-30 atoms), the average open-shell LNO-CCSD(T) correlation energies are found to be 99.9 to 99.95% accurate, which translates into average absolute deviations of a few tenths of kcal/mol in the investigated energy differences already with the default settings. For more extensive molecules, the local errors may grow, but they can be estimated and decreased via affordable systematic convergence studies. This enables the accurate modeling of large systems with complex electronic structures, as illustrated on open-shell organic radicals and transition-metal complexes of up to 179 atoms as well as on challenging biochemical systems, including up to 601 atoms and 11,000 basis functions. While the protein models involve difficulties for local approximations, such as the spin states of a bounded iron ion or an extremely delocalized singly occupied orbital, the corresponding single-node LNO-CCSD(T) computations were feasible in a matter of days with 10s to 100 GB of memory use. Therefore, the new LNO-CCSD(T) implementation enables highly accurate computations for open-shell systems of unprecedented size and complexity with widely accessible hardware.
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Affiliation(s)
- P. Bernát Szabó
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - József Csóka
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- HUN-REN-BME
Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- MTA-BME
Lendület Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Mihály Kállay
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- HUN-REN-BME
Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- MTA-BME
Lendület Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Péter R. Nagy
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- HUN-REN-BME
Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- MTA-BME
Lendület Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
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5
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Efremenko I, Martin JML. Coupled Cluster Benchmark of New DFT and Local Correlation Methods: Mechanisms of Hydroarylation and Oxidative Coupling Catalyzed by Ru(II, III) Chloride Carbonyls. J Phys Chem A 2021; 125:8987-8999. [PMID: 34586809 DOI: 10.1021/acs.jpca.1c05124] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have evaluated a set of accurate canonical CCSD(T) energies for stationary points on the potential energy surface for Ru(II, III) chloride carbonyl catalysis of two competing reactions between benzene and methyl acrylate (MA), namely, hydroarylation and oxidative coupling. We have then applied this set to evaluate the performance of localized orbital coupled-cluster methods and several new and common density functionals. We find that (a) DLPNO-CCSD(T) with TightPNO cutoffs is an acceptable substitute for full canonical CCSD(T) calculations on this system; (b) for the closed-shell systems where it could be applied, LNO-CCSD(T) with tight convergence criteria is very close to the canonical results; (c) the recent ωB97X-V and ωB97M-V functionals exhibit superior performance to commonly used DFT functionals in both closed- and open-shell calculations; (d) the revDSD-PBEP86 revision of the DSD-PBEP86 double hybrid represents an improvement over the original, even though transition metals were not involved in its parametrization; and (e) DSD-SCAN and DOD-SCAN show comparable efficiency. Most tested (meta)-GGA and hybrid density functionals perform better for open-shell than for closed-shell complexes; this is not the case for the double hybrids considered.
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Affiliation(s)
- Irena Efremenko
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Jan M L Martin
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, 7610001 Rehovot, Israel
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6
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Szabó PB, Csóka J, Kállay M, Nagy PR. Linear-Scaling Open-Shell MP2 Approach: Algorithm, Benchmarks, and Large-Scale Applications. J Chem Theory Comput 2021; 17:2886-2905. [PMID: 33819030 PMCID: PMC8154337 DOI: 10.1021/acs.jctc.1c00093] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
A linear-scaling
local second-order Møller–Plesset
(MP2) method is presented for high-spin open-shell molecules based
on restricted open-shell (RO) reference functions. The open-shell
local MP2 (LMP2) approach inherits the iteration- and redundancy-free
formulation and the completely integral-direct, OpenMP-parallel, and
memory and disk use economic algorithms of our closed-shell LMP2 implementation.
By utilizing restricted local molecular orbitals for the demanding
integral transformation step and by introducing a novel long-range
spin-polarization approximation, the computational cost of RO-LMP2
approaches that of closed-shell LMP2. Extensive benchmarks were performed
for reactions of radicals, ionization potentials, as well as spin-state
splittings of carbenes and transition-metal complexes. Compared to
the conventional MP2 reference for systems of up to 175 atoms, local
errors of at most 0.1 kcal/mol were found, which are well below the
intrinsic accuracy of MP2. RO-LMP2 computations are presented for
challenging protein models of up to 601 atoms and 11 000 basis
functions, which involve either spin states of a complexed iron ion
or a highly delocalized singly occupied orbital. The corresponding
runtimes of 9–15 h obtained with a single, many-core CPU demonstrate
that MP2, as well as spin-scaled MP2 and double-hybrid density functional
methods, become widely accessible for open-shell systems of unprecedented
size and complexity.
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Affiliation(s)
- P Bernát Szabó
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
| | - József Csóka
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
| | - Mihály Kállay
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
| | - Péter R Nagy
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
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7
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Hégely B, Nagy PR, Kállay M. Dual Basis Set Approach for Density Functional and Wave Function Embedding Schemes. J Chem Theory Comput 2018; 14:4600-4615. [DOI: 10.1021/acs.jctc.8b00350] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Bence Hégely
- MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
| | - Péter R. Nagy
- MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
| | - Mihály Kállay
- MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary
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8
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Fiedler B, Himmel D, Krossing I, Friedrich J. More Stable Template Localization for an Incremental Focal-Point Approach—Implementation and Application to the Intramolecular Decomposition of Tris-perfluoro- tert-butoxyalane. J Chem Theory Comput 2018; 14:557-571. [DOI: 10.1021/acs.jctc.7b00707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin Fiedler
- Institut
für Chemie, Technische Universität Chemnitz, 09111 Chemnitz, Germany
| | - Daniel Himmel
- Institut
für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Ingo Krossing
- Institut
für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Joachim Friedrich
- Institut
für Chemie, Technische Universität Chemnitz, 09111 Chemnitz, Germany
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9
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Fiedler B, Schmitz G, Hättig C, Friedrich J. Combining Accuracy and Efficiency: An Incremental Focal-Point Method Based on Pair Natural Orbitals. J Chem Theory Comput 2017; 13:6023-6042. [PMID: 29045786 DOI: 10.1021/acs.jctc.7b00654] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this work, we present a new pair natural orbitals (PNO)-based incremental scheme to calculate CCSD(T) and CCSD(T0) reaction, interaction, and binding energies. We perform an extensive analysis, which shows small incremental errors similar to previous non-PNO calculations. Furthermore, slight PNO errors are obtained by using TPNO = TTNO with appropriate values of 10-7 to 10-8 for reactions and 10-8 for interaction or binding energies. The combination with the efficient MP2 focal-point approach yields chemical accuracy relative to the complete basis-set (CBS) limit. In this method, small basis sets (cc-pVDZ, def2-TZVP) for the CCSD(T) part are sufficient in case of reactions or interactions, while some larger ones (e.g., (aug)-cc-pVTZ) are necessary for molecular clusters. For these larger basis sets, we show the very high efficiency of our scheme. We obtain not only tremendous decreases of the wall times (i.e., factors >102) due to the parallelization of the increment calculations as well as of the total times due to the application of PNOs (i.e., compared to the normal incremental scheme) but also smaller total times with respect to the standard PNO method. That way, our new method features a perfect applicability by combining an excellent accuracy with a very high efficiency as well as the accessibility to larger systems due to the separation of the full computation into several small increments.
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Affiliation(s)
- Benjamin Fiedler
- Institut für Chemie, Technische Universität Chemnitz , 09111 Chemnitz, Germany
| | - Gunnar Schmitz
- Institut for Kemi, Aarhus Universitet , 8000 Aarhus C, Denmark
| | - Christof Hättig
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Joachim Friedrich
- Institut für Chemie, Technische Universität Chemnitz , 09111 Chemnitz, Germany
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10
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Fiedler B, Coriani S, Friedrich J. Molecular Dipole Moments within the Incremental Scheme Using the Domain-Specific Basis-Set Approach. J Chem Theory Comput 2016; 12:3040-52. [PMID: 27300371 DOI: 10.1021/acs.jctc.6b00076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We present the first implementation of the fully automated incremental scheme for CCSD unrelaxed dipole moments using the domain-specific basis-set approach. Truncation parameters are varied, and the accuracy of the method is statistically analyzed for a test set of 20 molecules. The local approximations introduce small errors at second order and negligible ones at third order. For a third-order incremental CCSD expansion with a CC2 error correction, a cc-pVDZ/SV domain-specific basis set (tmain = 3.5 Bohr), and the truncation parameter f = 30 Bohr, we obtain a mean error of 0.00 mau (-0.20 mau) and a standard deviation of 1.95 mau (2.17 mau) for the total dipole moments (Cartesian components of the dipole vectors). By analyzing incremental CCSD energies, we demonstrate that the MP2 and CC2 error correction schemes are an exclusive correction for the domain-specific basis-set error. Our implementation of the incremental scheme provides fully automated computations of highly accurate dipole moments at reduced computational cost and is fully parallelized in terms of the calculation of the increments. Therefore, one can utilize the incremental scheme, on the same hardware, to extend the basis set in comparison to standard CCSD and thus obtain a better total accuracy.
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Affiliation(s)
- Benjamin Fiedler
- Institute for Chemistry, Technische Universität Chemnitz , Straße der Nationen 62, D-09111 Chemnitz, Germany
| | - Sonia Coriani
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste , Via L. Giorgieri 1, I-34127 Trieste, Italy.,Aarhus Institute of Advanced Studies, Aarhus University , Høegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark
| | - Joachim Friedrich
- Institute for Chemistry, Technische Universität Chemnitz , Straße der Nationen 62, D-09111 Chemnitz, Germany
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11
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Anacker T, Hill JG, Friedrich J. Optimized Basis Sets for the Environment in the Domain-Specific Basis Set Approach of the Incremental Scheme. J Phys Chem A 2016; 120:2443-58. [DOI: 10.1021/acs.jpca.6b01097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Tony Anacker
- Department
of Theoretical Chemistry, Chemnitz University of Technology, Straße
der Nationen 62, D-09111 Chemnitz, Germany
| | - J. Grant Hill
- Department
of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Joachim Friedrich
- Department
of Theoretical Chemistry, Chemnitz University of Technology, Straße
der Nationen 62, D-09111 Chemnitz, Germany
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12
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Anacker T, Tew DP, Friedrich J. First UHF Implementation of the Incremental Scheme for Open-Shell Systems. J Chem Theory Comput 2015; 12:65-78. [PMID: 26605975 DOI: 10.1021/acs.jctc.5b00933] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The incremental scheme makes it possible to compute CCSD(T) correlation energies to high accuracy for large systems. We present the first extension of this fully automated black-box approach to open-shell systems using an Unrestricted Hartree-Fock (UHF) wave function, extending the efficient domain-specific basis set approach to handle open-shell references. We test our approach on a set of organic and metal organic structures and molecular clusters and demonstrate standard deviations from canonical CCSD(T) values of only 1.35 kJ/mol using a triple ζ basis set. We find that the incremental scheme is significantly more cost-effective than the canonical implementation even for relatively small systems and that the ease of parallelization makes it possible to perform high-level calculations on large systems in a few hours on inexpensive computers. We show that the approximations that make our approach widely applicable are significantly smaller than both the basis set incompleteness error and the intrinsic error of the CCSD(T) method, and we further demonstrate that incremental energies can be reliably used in extrapolation schemes to obtain near complete basis set limit CCSD(T) reaction energies for large systems.
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Affiliation(s)
- Tony Anacker
- Institute for Chemistry, Chemnitz University of Technology , Straße der Nationen 62, D-09111 Chemnitz, Sachsen, Germany
| | - David P Tew
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - Joachim Friedrich
- Institute for Chemistry, Chemnitz University of Technology , Straße der Nationen 62, D-09111 Chemnitz, Sachsen, Germany
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13
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Cao X, Zhang J, Weissmann D, Dolg M, Chen X. Accurate quantum chemical modelling of the separation of Eu3+ from Am3+/Cm3+ by liquid–liquid extraction with Cyanex272. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp03100a] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The liquid–liquid extraction of Eu(iii) with Cyanex272 from aqueous solutions containing Eu(iii), Am(iii) and Cm(iii) is modeled with quantum chemical methods.
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Affiliation(s)
- Xiaoyan Cao
- Theoretical Chemistry
- University of Cologne
- 50939 Cologne
- Germany
| | - Jun Zhang
- Theoretical Chemistry
- University of Cologne
- 50939 Cologne
- Germany
| | | | - Michael Dolg
- Theoretical Chemistry
- University of Cologne
- 50939 Cologne
- Germany
| | - Xuebo Chen
- Department of Chemistry
- Beijing Normal University
- 100875 Beijing
- P. R. China
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