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Hou X, Chen F. Block Effective Hamiltonian Theory and Its Application. J Chem Theory Comput 2023; 19:61-70. [PMID: 36516513 DOI: 10.1021/acs.jctc.2c00820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Block effective Hamiltonian theory (BEHT) is presented in this work. Configuration interaction functions are divided into P, Q, and R spaces. Effective Hamiltonian is constructed with the partitioning technique within the P space. The eigenvalue problem of the effective Hamiltonian is then solved iteratively. It is demonstrated that the ground-state energies of N2, HF, and F2 calculated with BEHT converge to the multireference configuration interaction energies from below and the iteration number becomes smaller as BEHT energy becomes closer to the exact energy. The accuracy of BEHT is better than that of the second-order multireference perturbation theory, although the matrix elements in both methods are the same. The ionization potentials of the singlet state of HF, the doublet state of F, and the triplet state of NH and the potential energy curves of CH4, C2, and N2 are calculated with BEHT and compared with experiments and results of CASSCF, CCSD, and CCSD(T) and the results of the full configuration interaction if available. The iteration numbers are all less than 10 in this study. These calculations show the good performances of BEHT in comparison with other theoretical approximation methods.
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Affiliation(s)
- Xiangling Hou
- Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing100083, China.,Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Beijing100083, China
| | - Feiwu Chen
- Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing100083, China.,Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Beijing100083, China
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PITARCH-RUIZ JOSE, SANCHEZ-MARIN JOSE, DE MERAS ALFREDOSANCHEZ, MAYNAU DANIEL. The vertical spectrum of H2CO revisited: (SC)2-CI and CC calculations. Mol Phys 2009. [DOI: 10.1080/0026897021000034503] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- JOSE PITARCH-RUIZ
- a Departament de Quimica-Fisica , Institut de Ciencia Molecular, Facultat de Ciencies Quimiques, Universitat de Valencia , Dr. Moliner 50, E-46100 , Burjassot (Valencia) , Spain
| | - JOSE SANCHEZ-MARIN
- a Departament de Quimica-Fisica , Institut de Ciencia Molecular, Facultat de Ciencies Quimiques, Universitat de Valencia , Dr. Moliner 50, E-46100 , Burjassot (Valencia) , Spain
| | - ALFREDO SANCHEZ DE MERAS
- a Departament de Quimica-Fisica , Institut de Ciencia Molecular, Facultat de Ciencies Quimiques, Universitat de Valencia , Dr. Moliner 50, E-46100 , Burjassot (Valencia) , Spain
| | - DANIEL MAYNAU
- b Laboratoire de Physique Quantique, URA 505 , Université Paul Sabatier , 118 route de Narbonne, 31062 , Toulouse Cedex , France
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Pitarch-Ruiz J, Sánchez-Marín J, Lavín C, Velasco A, Martín I. Rydberg, valence and mixed states in the vertical spectrum of HF. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.06.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Villaume S, Strich A, Daniel C, Perera SA, Bartlett RJ. A coupled cluster study of the electronic spectroscopy and photochemistry of Cr(CO)6. Phys Chem Chem Phys 2007; 9:6115-22. [DOI: 10.1039/b709050a] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Size Consistent Properties from Size-consistent Self-consistent Configuration Interaction Coefficients. Theor Chem Acc 2006. [DOI: 10.1007/s00214-006-0116-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kamiya M, Hirata S. Higher-order equation-of-motion coupled-cluster methods for ionization processes. J Chem Phys 2006; 125:074111. [PMID: 16942326 DOI: 10.1063/1.2244570] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Compact algebraic equations defining the equation-of-motion coupled-cluster (EOM-CC) methods for ionization potentials (IP-EOM-CC) have been derived and computer implemented by virtue of a symbolic algebra system largely automating these processes. Models with connected cluster excitation operators truncated after double, triple, or quadruple level and with linear ionization operators truncated after two-hole-one-particle (2h1p), three-hole-two-particle (3h2p), or four-hole-three-particle (4h3p) level (abbreviated as IP-EOM-CCSD, CCSDT, and CCSDTQ, respectively) have been realized into parallel algorithms taking advantage of spin, spatial, and permutation symmetries with optimal size dependence of the computational costs. They are based on spin-orbital formalisms and can describe both alpha and beta ionizations from open-shell (doublet, triplet, etc.) reference states into ionized states with various spin magnetic quantum numbers. The application of these methods to Koopmans and satellite ionizations of N2 and CO (with the ambiguity due to finite basis sets eliminated by extrapolation) has shown that IP-EOM-CCSD frequently accounts for orbital relaxation inadequately and displays errors exceeding a couple of eV. However, these errors can be systematically reduced to tenths or even hundredths of an eV by IP-EOM-CCSDT or CCSDTQ. Comparison of spectroscopic parameters of the FH+ and NH+ radicals between IP-EOM-CC and experiments has also underscored the importance of higher-order IP-EOM-CC treatments. For instance, the harmonic frequencies of the A 2Sigma- state of NH+ are predicted to be 1285, 1723, and 1705 cm(-1) by IP-EOM-CCSD, CCSDT, and CCSDTQ, respectively, as compared to the observed value of 1707 cm(-1). The small adiabatic energy separation (observed 0.04 eV) between the X 2Pi and a 4Sigma- states of NH+ also requires IP-EOM-CCSDTQ for a quantitative prediction (0.06 eV) when the a 4Sigma- state has the low-spin magnetic quantum number (s(z) = 1/2). When the state with s(z) = 3/2 is sought, the energy separations converge much more rapidly with the IP-EOM-CCSD value (0.03 eV) already being close to the observed (0.04 eV).
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Affiliation(s)
- Muneaki Kamiya
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida 32611-8435, USA
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Ben Amor N, Villaume S, Maynau D, Daniel C. The electronic spectroscopy of transition metal carbonyls: The tough case of Cr(CO)6. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.02.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Rossi E, Emerson A, Evangelisti S. Common Data Format for Program Sharing and Integration. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/3-540-44862-4_34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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Pitarch-Ruiz J, Sánchez-Marín J, Maynau D. Vertical spectrum of the C2H2+ system. An open shell (SC)2-CAS-SDCI study. J Comput Chem 2003; 24:609-17. [PMID: 12632475 DOI: 10.1002/jcc.10183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The open shell (SC)(2)-CAS-SDCI method along with a basis set of atomic natural orbitals (ANO) has been applied for calculating the main ionization potentials of acetylene, as well as the manifold of excited states of the different symmetries up to 32 eV. In this method, the single and double excitations of a CAS space are generated and the corresponding CI matrix is corrected by means of the (SC)(2) procedure that cancels the size-extensivity error and adds some high order contributions. The mean absolute error for the outer-valence X (2)Pi(u)(1pi(u) (-1)), A (2)Sigma(g) (+)(3sigma(g) (-1)), and B (2)Sigma(u) (+)(2sigma(u) (-1)) states, and the inner-valence C (2)Sigma(g) (+)(2sigma(g) (-1)) state is 0.1 eV. The excited states of C(2)H(2) (+) corresponding to the Sigma(g) (+), Sigma(u) (+), Pi(g), Pi(u), Delta(g), and Delta(u) symmetries are reported and their composition is discussed. The results are thoroughly compared to the best available multireference CI calculations. Recent multichannel CI results by Wells and Lucchese [J Chem Phys 1999, 110, 6365] have been used also as a guide for the discussion of the results. Discrepancies in the description of many multiconfigurational states by means of the (SC)(2)-CAS-SDCI wave function as compared to previous large MR-CI calculations are significant and are, consequently, remarked on. A large mixing of the 3sigma(g) (-1) and 2sigma(g) (-1) processes is found in the A (2)Sigma(g) (+) and C (2)Sigma(g) (+) states, provided that the basis set is augmented with Rydberg functions.
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Affiliation(s)
- José Pitarch-Ruiz
- Departament de Química-Física, Institut de Ciència Molecular, Facultat de Ciències Químiques, Universitat de València, Dr. Moliner, 50, E-46100 Burjassot (València), Spain
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Calzado CJ, Evangelisti S, Maynau D. Multi-reference configuration interaction using localized orbitals: a test study on HN. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0166-1280(02)00533-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Pitarch-Ruiz J, Sánchez-Marín J, Maynau D. Reducing CAS-SDCI space. Using selected spaces in configuration interaction calculations in an efficient way. J Comput Chem 2002; 23:1157-65. [PMID: 12116385 DOI: 10.1002/jcc.10092] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new method is presented, which allows an important reduction of the size of some Configuration Interaction (CI) matrices. Starting from a Complete Active Space (CAS), the numerous configurations that have a small weight in the CAS wave function are eliminated. When excited configurations (e.g., singly and doubly excited) are added to the reference space, the resulting MR-SDCI space is reduced in the same proportion as compared with the full CAS-SDCI. A set of active orbitals is chosen, but some selection of the most relevant excitations is performed because not all the possible excitations act as SDCI generators. Thanks to a new addressing technique, the computational time is drastically reduced, because the new addressing of the selected active space is as efficient as the addressing of the CAS. The presentation of the method is followed by two test calculations on the N(2) and HCCH molecules. For the N(2) the FCI results are taken as a benchmark reference. The outer valence ionization potentials of HCCH are compared to the experimental values. Both examples allow to test the accuracy of the MR-SDCI compared to that of the corresponding CAS-SDCI, despite the noticeable reduction of the CI space. The algorithm is suitable for the dressing techniques that allow for the correction of the size-extensivity error. The corrected results are also shown and discussed.
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Affiliation(s)
- José Pitarch-Ruiz
- Departament de Química-Física, Institut de Ciència Molecular, Universitat de València, Dr. Moliner, 50 E-46100 Burjassot (València), Spain
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Cabrero J, Calzado CJ, Maynau D, Caballol R, Malrieu JP. Metal−Ligand Delocalization in Magnetic Orbitals of Binuclear Complexes. J Phys Chem A 2002. [DOI: 10.1021/jp0204410] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jesús Cabrero
- Departament de Química Física i Inorgànica and Institut d’Estudis Avançats, Universitat Rovira i Virgili, Pl. Imperial Tarraco 1, 43005 Tarragona, Spain, and Laboratoire de Physique Quantique, IRSAMC, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
| | - Carmen J. Calzado
- Departament de Química Física i Inorgànica and Institut d’Estudis Avançats, Universitat Rovira i Virgili, Pl. Imperial Tarraco 1, 43005 Tarragona, Spain, and Laboratoire de Physique Quantique, IRSAMC, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
| | - Daniel Maynau
- Departament de Química Física i Inorgànica and Institut d’Estudis Avançats, Universitat Rovira i Virgili, Pl. Imperial Tarraco 1, 43005 Tarragona, Spain, and Laboratoire de Physique Quantique, IRSAMC, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
| | - Rosa Caballol
- Departament de Química Física i Inorgànica and Institut d’Estudis Avançats, Universitat Rovira i Virgili, Pl. Imperial Tarraco 1, 43005 Tarragona, Spain, and Laboratoire de Physique Quantique, IRSAMC, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
| | - Jean Paul Malrieu
- Departament de Química Física i Inorgànica and Institut d’Estudis Avançats, Universitat Rovira i Virgili, Pl. Imperial Tarraco 1, 43005 Tarragona, Spain, and Laboratoire de Physique Quantique, IRSAMC, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
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Pitarch-Ruiz J, Sánchez-Marín J, Martín I, Velasco AM. Vertical Excitation Energies and Ionization Potentials of H2S. A Size-Consistent Self-Consistent Singles and Doubles Configuration Interaction (SC)2-MR-SDCI Calculation. J Phys Chem A 2002. [DOI: 10.1021/jp020522w] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Martín I, Lavín C, Pérez-Delgado Y, Pitarch-Ruiz J, Sánchez-Marín J. Excitation Energies and Molecular Quantum Defect Orbital Transition Intensities for Rydberg States of ArH. J Phys Chem A 2001. [DOI: 10.1021/jp0106045] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pitarch-Ruiz J, Sánchez-Marı́n J, Maynau D, Heully J. The effect of correcting the size-extensivity error in singles and doubles configuration interaction excitation energies. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0166-1280(00)00664-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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