1
|
Nakano K, Sorella S, Alfè D, Zen A. Beyond Single-Reference Fixed-Node Approximation in Ab Initio Diffusion Monte Carlo Using Antisymmetrized Geminal Power Applied to Systems with Hundreds of Electrons. J Chem Theory Comput 2024; 20:4591-4604. [PMID: 38788330 PMCID: PMC11171267 DOI: 10.1021/acs.jctc.4c00139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/05/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024]
Abstract
Diffusion Monte Carlo (DMC) is an exact technique to project out the ground state (GS) of a Hamiltonian. Since the GS is always bosonic, in Fermionic systems, the projection needs to be carried out while imposing antisymmetric constraints, which is a nondeterministic polynomial hard problem. In practice, therefore, the application of DMC on electronic structure problems is made by employing the fixed-node (FN) approximation, consisting of performing DMC with the constraint of having a fixed, predefined nodal surface. How do we get the nodal surface? The typical approach, applied in systems having up to hundreds or even thousands of electrons, is to obtain the nodal surface from a preliminary mean-field approach (typically, a density functional theory calculation) used to obtain a single Slater determinant. This is known as single reference. In this paper, we propose a new approach, applicable to systems as large as the C60 fullerene, which improves the nodes by going beyond the single reference. In practice, we employ an implicitly multireference ansatz (antisymmetrized geminal power wave function constraint with molecular orbitals), initialized on the preliminary mean-field approach, which is relaxed by optimizing a few parameters of the wave function determining the nodal surface by minimizing the FN-DMC energy. We highlight the improvements of the proposed approach over the standard single-reference method on several examples and, where feasible, the computational gain over the standard multireference ansatz, which makes the methods applicable to large systems. We also show that physical properties relying on relative energies, such as binding energies, are affordable and reliable within the proposed scheme.
Collapse
Affiliation(s)
- Kousuke Nakano
- Center
for Basic Research on Materials, National
Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047, Japan
- International
School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - Sandro Sorella
- International
School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - Dario Alfè
- Dipartimento
di Fisica Ettore Pancini, Università
di Napoli Federico II, Monte S. Angelo, 80126 Napoli, Italy
- Department
of Earth Sciences, University College London, Gower Street, London WC1E 6BT, U.K.
- Thomas
Young Centre and London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, U.K.
| | - Andrea Zen
- Dipartimento
di Fisica Ettore Pancini, Università
di Napoli Federico II, Monte S. Angelo, 80126 Napoli, Italy
- Department
of Earth Sciences, University College London, Gower Street, London WC1E 6BT, U.K.
| |
Collapse
|
2
|
Dutta R, Gao F, Khamoshi A, Henderson TM, Scuseria GE. Correlated pair ansatz with a binary tree structure. J Chem Phys 2024; 160:084113. [PMID: 38421064 DOI: 10.1063/5.0185375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/02/2024] [Indexed: 03/02/2024] Open
Abstract
We develop an efficient algorithm to implement the recently introduced binary tree state (BTS) ansatz on a classical computer. BTS allows a simple approximation to permanents arising from the computationally intractable antisymmetric product of interacting geminals and respects size-consistency. We show how to compute BTS overlap and reduced density matrices efficiently. We also explore two routes for developing correlated BTS approaches: Jastrow coupled cluster on BTS and linear combinations of BT states. The resulting methods show great promise in benchmark applications to the reduced Bardeen-Cooper-Schrieffer Hamiltonian and the one-dimensional XXZ Heisenberg Hamiltonian.
Collapse
Affiliation(s)
- Rishab Dutta
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
| | - Fei Gao
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Armin Khamoshi
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Thomas M Henderson
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Gustavo E Scuseria
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| |
Collapse
|
3
|
Motta M, Sung KJ, Whaley KB, Head-Gordon M, Shee J. Bridging physical intuition and hardware efficiency for correlated electronic states: the local unitary cluster Jastrow ansatz for electronic structure. Chem Sci 2023; 14:11213-11227. [PMID: 37860666 PMCID: PMC10583744 DOI: 10.1039/d3sc02516k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/20/2023] [Indexed: 10/21/2023] Open
Abstract
A prominent goal in quantum chemistry is to solve the molecular electronic structure problem for ground state energy with high accuracy. While classical quantum chemistry is a relatively mature field, the accurate and scalable prediction of strongly correlated states found, e.g., in bond breaking and polynuclear transition metal compounds remains an open problem. Within the context of a variational quantum eigensolver, we propose a new family of ansatzes which provides a more physically appropriate description of strongly correlated electrons than a unitary coupled cluster with single and double excitations (qUCCSD), with vastly reduced quantum resource requirements. Specifically, we present a set of local approximations to the unitary cluster Jastrow wavefunction motivated by Hubbard physics. As in the case of qUCCSD, exactly computing the energy scales factorially with system size on classical computers but polynomially on quantum devices. The local unitary cluster Jastrow ansatz removes the need for SWAP gates, can be tailored to arbitrary qubit topologies (e.g., square, hex, and heavy-hex), and is well-suited to take advantage of continuous sets of quantum gates recently realized on superconducting devices with tunable couplers. The proposed family of ansatzes demonstrates that hardware efficiency and physical transparency are not mutually exclusive; indeed, chemical and physical intuition regarding electron correlation can illuminate a useful path towards hardware-friendly quantum circuits.
Collapse
Affiliation(s)
- Mario Motta
- IBM Quantum, IBM Research - Almaden San Jose CA 95120 USA
| | - Kevin J Sung
- IBM Quantum, IBM T. J. Watson Research Center Yorktown Heights NY 10598 USA
| | - K Birgitta Whaley
- Department of Chemistry, University of California Berkeley CA 94720 USA
- Berkeley Quantum Information and Computation Center, University of California Berkeley CA 94720 USA
- Challenge Institute for Quantum Computation, University of California Berkeley CA 94720 USA
| | - Martin Head-Gordon
- Department of Chemistry, University of California Berkeley CA 94720 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - James Shee
- Department of Chemistry, University of California Berkeley CA 94720 USA
- Department of Chemistry, Rice University Houston TX 77005 USA
| |
Collapse
|
4
|
Khamoshi A, Dutta R, Scuseria GE. State Preparation of Antisymmetrized Geminal Power on a Quantum Computer without Number Projection. J Phys Chem A 2023; 127:4005-4014. [PMID: 37129503 DOI: 10.1021/acs.jpca.3c00525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The antisymmetrized geminal power (AGP) is equivalent to the number projected Bardeen-Cooper-Schrieffer (PBCS) wave function. It is also an elementary symmetric polynomial (ESP) state. We generalize previous research on deterministically implementing the Dicke state to a state preparation algorithm for an ESP state, or equivalently AGP, on a quantum computer. Our method is deterministic and has polynomial cost, and it does not rely on number symmetry breaking and restoration. We also show that our circuit is equivalent to a disentangled unitary paired coupled cluster operator and a layer of unitary Jastrow operator acting on a single Slater determinant. The method presented herein highlights the ability of disentangled unitary coupled cluster to capture nontrivial entanglement properties that are hardly accessible with traditional Hartree-Fock based electronic structure methods.
Collapse
Affiliation(s)
- Armin Khamoshi
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Rishab Dutta
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Gustavo E Scuseria
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| |
Collapse
|
5
|
Hanson-Heine MWD. Static Electron Correlation in Anharmonic Molecular Vibrations: A Hybrid TAO-DFT Study. J Phys Chem A 2022; 126:7273-7282. [PMID: 36164938 PMCID: PMC9574917 DOI: 10.1021/acs.jpca.2c05881] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hybrid thermally-assisted-occupation density functional theory is used to examine the effects of static electron correlation on the prediction of a benchmark set of experimentally observed molecular vibrational frequencies. The B3LYP and B97-1 thermally-assisted-occupation measure of static electron correlation is important for describing the vibrations of many of the molecules that make up several popular test sets of experimental data. Shifts are seen for known multireference systems and for many molecules containing atoms from the second row of the periodic table of elements. Several molecules only show significant shifts in select vibrational modes, and significant improvements are seen for the prediction of hydrogen stretching frequencies throughout the test set.
Collapse
|
6
|
Zhang SX, Wan ZQ, Lee CK, Hsieh CY, Zhang S, Yao H. Variational Quantum-Neural Hybrid Eigensolver. PHYSICAL REVIEW LETTERS 2022; 128:120502. [PMID: 35394326 DOI: 10.1103/physrevlett.128.120502] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/22/2021] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
The variational quantum eigensolver (VQE) is one of the most representative quantum algorithms in the noisy intermediate-scale quantum (NISQ) era, and is generally speculated to deliver one of the first quantum advantages for the ground-state simulations of some nontrivial Hamiltonians. However, short quantum coherence time and limited availability of quantum hardware resources in the NISQ hardware strongly restrain the capacity and expressiveness of VQEs. In this Letter, we introduce the variational quantum-neural hybrid eigensolver (VQNHE) in which the shallow-circuit quantum Ansatz can be further enhanced by classical post-processing with neural networks. We show that the VQNHE consistently and significantly outperforms the VQE in simulating ground-state energies of quantum spins and molecules given the same amount of quantum resources. More importantly, we demonstrate that, for arbitrary postprocessing neural functions, the VQNHE only incurs a polynomial overhead of processing time and represents the first scalable method to exponentially accelerate the VQE with nonunitary postprocessing that can be efficiently implemented in the NISQ era.
Collapse
Affiliation(s)
- Shi-Xin Zhang
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
- Tencent Quantum Laboratory, Tencent, Shenzhen, Guangdong 518057, China
| | - Zhou-Quan Wan
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
- Tencent Quantum Laboratory, Tencent, Shenzhen, Guangdong 518057, China
| | | | - Chang-Yu Hsieh
- Tencent Quantum Laboratory, Tencent, Shenzhen, Guangdong 518057, China
| | - Shengyu Zhang
- Tencent Quantum Laboratory, Tencent, Shenzhen, Guangdong 518057, China
| | - Hong Yao
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
| |
Collapse
|
7
|
Benfenati F, Mazzola G, Capecci C, Barkoutsos PK, Ollitrault PJ, Tavernelli I, Guidoni L. Improved Accuracy on Noisy Devices by Nonunitary Variational Quantum Eigensolver for Chemistry Applications. J Chem Theory Comput 2021; 17:3946-3954. [PMID: 34077220 DOI: 10.1021/acs.jctc.1c00091] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We propose a modification of the Variational Quantum Eigensolver algorithm for electronic structure optimization using quantum computers, named nonunitary Variational Quantum Eigensolver (nu-VQE), in which a nonunitary operator is combined with the original system Hamiltonian leading to a new variational problem with a simplified wave function ansatz. In the present work, as nonunitary operator, we use the Jastrow factor, inspired from classical Quantum Monte Carlo techniques for simulation of strongly correlated electrons. The method is applied to prototypical molecular Hamiltonians for which we obtain accurate ground-state energies with shallower circuits, at the cost of an increased number of measurements. Finally, we also show that this method achieves an important error mitigation effect that drastically improves the quality of the results for VQE optimizations on today's noisy quantum computers. The absolute error in the calculated energy within our scheme is 1 order of magnitude smaller than the corresponding result using traditional VQE methods, with the same circuit depth.
Collapse
Affiliation(s)
- Francesco Benfenati
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Coppito, L'Aquila 67100, Italy.,Multiverse Computing, Donostia-San Sebastián 20014, Spain
| | | | - Chiara Capecci
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Coppito, L'Aquila 67100, Italy.,Dipartimento di Fisica, Sapienza Università di Roma, Roma 00185, Italy
| | | | | | | | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Coppito, L'Aquila 67100, Italy
| |
Collapse
|
8
|
Genovese C, Sorella S. The nature of the chemical bond in the dicarbon molecule. J Chem Phys 2020; 153:164301. [DOI: 10.1063/5.0023067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Claudio Genovese
- SISSA—International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| | - Sandro Sorella
- SISSA—International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| |
Collapse
|
9
|
Genovese C, Shirakawa T, Nakano K, Sorella S. General Correlated Geminal Ansatz for Electronic Structure Calculations: Exploiting Pfaffians in Place of Determinants. J Chem Theory Comput 2020; 16:6114-6131. [PMID: 32804497 PMCID: PMC8011928 DOI: 10.1021/acs.jctc.0c00165] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Indexed: 11/29/2022]
Abstract
We propose here a single Pfaffian correlated variational ansatz that dramatically improves the accuracy with respect to the single determinant one, while remaining at a similar computational cost. A much larger correlation energy is indeed determined by the most general two electron pairing function, including both singlet and triplet channels, combined with a many-body Jastrow factor, including all possible spin-spin, spin-density, and density-density terms. The main technical ingredient to exploit this accuracy is the use of the Pfaffian for antisymmetrizing a highly correlated pairing function, thus recovering the Fermi statistics for electrons with an affordable computational cost. Moreover, the application of the diffusion Monte Carlo, within the fixed node approximation, allows us to obtain very accurate binding energies for the first preliminary calculations reported in this study: C2, N2, and O2 and the benzene molecule. This is promising and remarkable, considering that they represent extremely difficult molecules even for computationally demanding multideterminant approaches, and opens therefore the way for realistic and accurate electronic simulations with an algorithm scaling at most as the fourth power of the number of electrons.
Collapse
Affiliation(s)
- Claudio Genovese
- SISSA,
International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| | - Tomonori Shirakawa
- Computational
Materials Science Research Team, RIKEN Center
for Computational Science (R-CCS), Kobe, Hyogo 650-0047, Japan
| | - Kousuke Nakano
- SISSA,
International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
- School
of Information Science, Japan Advanced Institute
of Science and Technology (JAIST), Asahidai 1-1, Nomi, Ishikawa 923-1292, Japan
| | - Sandro Sorella
- SISSA,
International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| |
Collapse
|
10
|
Dutta R, Henderson TM, Scuseria GE. Geminal Replacement Models Based on AGP. J Chem Theory Comput 2020; 16:6358-6367. [DOI: 10.1021/acs.jctc.0c00807] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rishab Dutta
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Thomas M. Henderson
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Gustavo E. Scuseria
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| |
Collapse
|
11
|
Nakano K, Attaccalite C, Barborini M, Capriotti L, Casula M, Coccia E, Dagrada M, Genovese C, Luo Y, Mazzola G, Zen A, Sorella S. TurboRVB: A many-body toolkit for ab initio electronic simulations by quantum Monte Carlo. J Chem Phys 2020; 152:204121. [DOI: 10.1063/5.0005037] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Kousuke Nakano
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Japan Advanced Institute of Science and Technology (JAIST), Asahidai 1-1, Nomi, Ishikawa 923-1292, Japan
| | - Claudio Attaccalite
- Aix-Marseille Université, CNRS, CINaM UMR 7325, Campus de Luminy, 13288 Marseille, France
| | | | - Luca Capriotti
- New York University, Tandon School of Engineering, 6 MetroTech Center, Brooklyn, New York 11201, USA
- Department of Mathematics, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Michele Casula
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, IRD UMR 206, MNHN, 4 Place Jussieu, 75252 Paris, France
| | - Emanuele Coccia
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Mario Dagrada
- Forescout Technologies, John F. Kennedylaan 2, 5612AB Eindhoven, The Netherlands
| | - Claudio Genovese
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - Ye Luo
- Computational Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
- Argonne Leadership Computing Facility, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
| | | | - Andrea Zen
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Thomas Young Centre and London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Sandro Sorella
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| |
Collapse
|
12
|
Zen A, Brandenburg JG, Michaelides A, Alfè D. A new scheme for fixed node diffusion quantum Monte Carlo with pseudopotentials: Improving reproducibility and reducing the trial-wave-function bias. J Chem Phys 2019; 151:134105. [DOI: 10.1063/1.5119729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Andrea Zen
- Thomas Young Centre, University College London, London WC1H 0AH, United Kingdom
- London Centre for Nanotechnology, Gordon St., London WC1H 0AH, United Kingdom
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- Department of Earth Sciences, University College London, London WC1E 6BT, United Kingdom
| | - Jan Gerit Brandenburg
- Thomas Young Centre, University College London, London WC1H 0AH, United Kingdom
- Interdisciplinary Center for Scientific Computing, University of Heidelberg, Im Neuenheimer Feld 205A, 69120 Heidelberg, Germany
| | - Angelos Michaelides
- Thomas Young Centre, University College London, London WC1H 0AH, United Kingdom
- London Centre for Nanotechnology, Gordon St., London WC1H 0AH, United Kingdom
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Dario Alfè
- Thomas Young Centre, University College London, London WC1H 0AH, United Kingdom
- London Centre for Nanotechnology, Gordon St., London WC1H 0AH, United Kingdom
- Department of Earth Sciences, University College London, London WC1E 6BT, United Kingdom
- Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II, Monte S. Angelo, I-80126 Napoli, Italy
| |
Collapse
|
13
|
Mazzola G, Ollitrault PJ, Barkoutsos PK, Tavernelli I. Nonunitary Operations for Ground-State Calculations in Near-Term Quantum Computers. PHYSICAL REVIEW LETTERS 2019; 123:130501. [PMID: 31697518 DOI: 10.1103/physrevlett.123.130501] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Indexed: 06/10/2023]
Abstract
We introduce a quantum Monte Carlo inspired reweighting scheme to accurately compute energies from optimally short quantum circuits. This effectively hybrid quantum-classical approach features both entanglement provided by a short quantum circuit, and the presence of an effective nonunitary operator at the same time. The functional form of this projector is borrowed from classical computation and is able to filter out high-energy components generated by a suboptimal variational quantum heuristic Ansatz. The accuracy of this approach is demonstrated numerically in finding energies of entangled ground states of many-body lattice models. We demonstrate a practical implementation on IBM quantum hardware up to an 8-qubit circuit.
Collapse
Affiliation(s)
| | - Pauline J Ollitrault
- IBM Research Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Ivano Tavernelli
- IBM Research Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| |
Collapse
|
14
|
Zhou X, Wang F. Singlet-triplet gaps in diradicals obtained with diffusion quantum Monte Carlo using a Slater-Jastrow trial wavefunction with a minimum number of determinants. Phys Chem Chem Phys 2019; 21:20422-20431. [PMID: 31501831 DOI: 10.1039/c9cp03045j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diradicals are essential species in a wide range of chemical processes, whereas the computational study of their electronic structure often remains a challenge due to near-degeneracy of the frontier molecular orbitals. The fixed-node diffusion quantum Monte Carlo (FN-DMC) method is employed to calculate adiabatic energy gaps of some typical diradicals with the Slater-Jastrow trial wavefunction. The antisymmetrized part of the trial wavefunction is taken to be a linear combination of a minimum number of determinants using RB3LYP orbitals from the closed-shell singlet state or ROB3LYP orbitals from the triplet state. Our results show that using the two-determinant-Jastrow trial wavefunction is necessary to achieve reliable energy differences between closed-shell singlet states. The energy of the triplet state with MS = 1 is calculated to be lower than that with MS = 0 with FN-DMC even using trial wavefunctions with spin-pure states as their antisymmetrized parts and this difference is reduced with better orbitals. This indicates that the fixed-node error is smaller for the triplet state with MS = 1. Adiabatic energy gaps obtained from the present FN-DMC calculations are in reasonable agreement with available experimental values. Compared with results of the high level EOM-SF-CC method, energy gaps of FN-DMC with RB3LYP orbitals are slightly better than those using ROB3LYP orbitals and results of EOM-SF-CCSD. The present FN-DMC calculations using the simplest ansatz for the trial wavefunction can achieve reasonable results for these diradicals and they can readily be applied to large diradicals.
Collapse
Affiliation(s)
- Xiaojun Zhou
- Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu, P. R. China.
| | | |
Collapse
|
15
|
Nakano K, Maezono R, Sorella S. All-Electron Quantum Monte Carlo with Jastrow Single Determinant Ansatz: Application to the Sodium Dimer. J Chem Theory Comput 2019; 15:4044-4055. [DOI: 10.1021/acs.jctc.9b00295] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kousuke Nakano
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136, Trieste, Italy
- School of Information Science, Japan Advanced Institute of Science and Technology (JAIST), Asahidai 1-1, Nomi, Ishikawa 923-1292, Japan
| | - Ryo Maezono
- School of Information Science, Japan Advanced Institute of Science and Technology (JAIST), Asahidai 1-1, Nomi, Ishikawa 923-1292, Japan
- Computational Engineering Applications Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Sandro Sorella
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136, Trieste, Italy
| |
Collapse
|
16
|
Souri M, Mohammadi K. Theoretical investigation of the defect position effect on the NLO properties of N and B doped graphenes. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
17
|
Barborini M, Sorella S, Rontani M, Corni S. Angle-resolved photoemission spectroscopy from first-principles quantum Monte Carlo. J Chem Phys 2018; 149:154102. [DOI: 10.1063/1.5038864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
| | - Sandro Sorella
- Scuola Internazionale Superiore di Studi Avanzati (SISSA) and CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy
| | | | - Stefano Corni
- CNR-NANO, Via Campi 213/a, 41125 Modena, Italy
- Dipartimento di Scienze Chimiche—Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| |
Collapse
|
18
|
Abstract
Fascia is a cacophony of functions and information, a completely adaptable entropy complex. The fascial system has a solid and a liquid component, acting in a perfect symbiotic synchrony. Each cell communicates with the other cells by sending and receiving signals; this concept is a part of quantum physics and it is known as quantum entanglement: a physical system cannot be described individually, but only as a juxtaposition of multiple systems, where the measurement of a quantity determines the value for other systems. Fascial continuum serves as a target for different manual approaches, such as physiotherapy, osteopathy and chiropractic. Cellular behaviour and the inclusion of quantum physics background are hardly being considered to find out what happens between the operator and the patient during a manual physical contact. The article examines these topics. According to the authors' knowledge, this is the first scientific text to offer manual operators’ new perspectives to understand what happens during palpatory contact. A fascial cell has not only memory but also the awareness of the mechanometabolic information it feels, and it has the anticipatory predisposition in preparing itself for alteration of its natural environment.
Collapse
Affiliation(s)
- Bruno Bordoni
- Cardiology, Foundation Don Carlo Gnocchi / (IRCCS) Institute of Hospitalization and Care, Milano, ITA
| | - Marta Simonelli
- Osteopathy, (SOFI) School of French-Italian Osteopathy, Pisa, ITA
| |
Collapse
|
19
|
Sorella S, Seki K, Brovko OO, Shirakawa T, Miyakoshi S, Yunoki S, Tosatti E. Correlation-Driven Dimerization and Topological Gap Opening in Isotropically Strained Graphene. PHYSICAL REVIEW LETTERS 2018; 121:066402. [PMID: 30141665 DOI: 10.1103/physrevlett.121.066402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Indexed: 06/08/2023]
Abstract
The phase diagram of isotropically expanded graphene cannot be correctly predicted by ignoring either electron correlations, or mobile carbons, or the effect of applied stress, as was done so far. We calculate the ground state enthalpy (not just energy) of strained graphene by an accurate off-lattice quantum Monte Carlo correlated ansatz of great variational flexibility. Following undistorted semimetallic graphene at low strain, multideterminant Heitler-London correlations stabilize between ≃8.5% and ≃15% strain an insulating Kekulé-like dimerized (DIM) state. Closer to a crystallized resonating-valence bond than to a Peierls state, the DIM state prevails over the competing antiferromagnetic insulating state favored by density-functional calculations which we conduct in parallel. The DIM stressed graphene insulator, whose gap is predicted to grow in excess of 1 eV before failure near 15% strain, is topological in nature, implying under certain conditions 1D metallic interface states lying in the bulk energy gap.
Collapse
Affiliation(s)
- Sandro Sorella
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Democritos Simulation Center CNR-IOM Istituto Officina dei Materiali, Via Bonomea 265, 34136 Trieste, Italy
- Computational Materials Science Research Team, RIKEN Center for Computational Science (R-CCS), Hyogo 650-0047, Japan
| | - Kazuhiro Seki
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Computational Materials Science Research Team, RIKEN Center for Computational Science (R-CCS), Hyogo 650-0047, Japan
- Computational Condensed Matter Physics Laboratory, RIKEN Cluster for Pioneering Research (CPR), Saitama 351-0198, Japan
| | - Oleg O Brovko
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
| | - Tomonori Shirakawa
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Computational Materials Science Research Team, RIKEN Center for Computational Science (R-CCS), Hyogo 650-0047, Japan
- Computational Condensed Matter Physics Laboratory, RIKEN Cluster for Pioneering Research (CPR), Saitama 351-0198, Japan
- Computational Quantum Matter Research Team, RIKEN, Center for Emergent Matter Science (CEMS), Saitama 351-0198, Japan
| | - Shohei Miyakoshi
- Computational Quantum Matter Research Team, RIKEN, Center for Emergent Matter Science (CEMS), Saitama 351-0198, Japan
| | - Seiji Yunoki
- Computational Materials Science Research Team, RIKEN Center for Computational Science (R-CCS), Hyogo 650-0047, Japan
- Computational Condensed Matter Physics Laboratory, RIKEN Cluster for Pioneering Research (CPR), Saitama 351-0198, Japan
- Computational Quantum Matter Research Team, RIKEN, Center for Emergent Matter Science (CEMS), Saitama 351-0198, Japan
| | - Erio Tosatti
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Democritos Simulation Center CNR-IOM Istituto Officina dei Materiali, Via Bonomea 265, 34136 Trieste, Italy
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
| |
Collapse
|
20
|
Dupuy N, Casula M. Fate of the open-shell singlet ground state in the experimentally accessible acenes: A quantum Monte Carlo study. J Chem Phys 2018; 148:134112. [DOI: 10.1063/1.5016494] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Nicolas Dupuy
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, IRD UMR 206, MNHN, 4 Place Jussieu, 75252 Paris, France
| | - Michele Casula
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, IRD UMR 206, MNHN, 4 Place Jussieu, 75252 Paris, France
| |
Collapse
|
21
|
Benavides-Riveros CL, Lathiotakis NN, Marques MAL. Towards a formal definition of static and dynamic electronic correlations. Phys Chem Chem Phys 2018; 19:12655-12664. [PMID: 28474027 DOI: 10.1039/c7cp01137g] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Some of the most spectacular failures of density-functional and Hartree-Fock theories are related to an incorrect description of the so-called static electron correlation. Motivated by recent progress in the N-representability problem of the one-body density matrix for pure states, we propose a method to quantify the static contribution to the electronic correlation. By studying several molecular systems we show that our proposal correlates well with our intuition of static and dynamic electron correlation. Our results bring out the paramount importance of the occupancy of the highest occupied natural spin-orbital in such quantification.
Collapse
|
22
|
Souri M, Kazemi T. Substitution effect in 2-spiropropane-1,3-diyl derivatives: A DFT and CASSCF study. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.10.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
23
|
Mussard B, Coccia E, Assaraf R, Otten M, Umrigar CJ, Toulouse J. Time-Dependent Linear-Response Variational Monte Carlo. ADVANCES IN QUANTUM CHEMISTRY 2018. [DOI: 10.1016/bs.aiq.2017.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
|
24
|
Combined complete active space configuration interaction and perturbation theory applied to conformational energy prototypes: Rotation and inversion barriers. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
25
|
Coccia E, Varsano D, Guidoni L. Theoretical S1 ← S0 Absorption Energies of the Anionic Forms of Oxyluciferin by Variational Monte Carlo and Many-Body Green’s Function Theory. J Chem Theory Comput 2017; 13:4357-4367. [DOI: 10.1021/acs.jctc.7b00505] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Emanuele Coccia
- S3
Center, CNR Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
| | - Daniele Varsano
- S3
Center, CNR Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
| | - Leonardo Guidoni
- Dipartimento
di Scienze Fisiche e Chimiche, Universitá degli Studi dell’Aquila, via Vetoio, 67100, L’Aquila, Italy
| |
Collapse
|
26
|
Gasperich K, Deible M, Jordan KD. H4: A model system for assessing the performance of diffusion Monte Carlo calculations using a single Slater determinant trial function. J Chem Phys 2017; 147:074106. [DOI: 10.1063/1.4986216] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kevin Gasperich
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Michael Deible
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Kenneth D. Jordan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| |
Collapse
|
27
|
Al-Hamdani YS, Rossi M, Alfè D, Tsatsoulis T, Ramberger B, Brandenburg JG, Zen A, Kresse G, Grüneis A, Tkatchenko A, Michaelides A. Properties of the water to boron nitride interaction: From zero to two dimensions with benchmark accuracy. J Chem Phys 2017; 147:044710. [DOI: 10.1063/1.4985878] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yasmine S. Al-Hamdani
- Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH, United Kingdom
- Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Mariana Rossi
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Dario Alfè
- Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH, United Kingdom
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Theodoros Tsatsoulis
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - Benjamin Ramberger
- University of Vienna, Faculty of Physics and Center for Computational Materials Sciences, Sensengasse 8/12, 1090 Wien, Austria
| | - Jan Gerit Brandenburg
- Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH, United Kingdom
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AH, United Kingdom
| | - Andrea Zen
- Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH, United Kingdom
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Georg Kresse
- University of Vienna, Faculty of Physics and Center for Computational Materials Sciences, Sensengasse 8/12, 1090 Wien, Austria
| | - Andreas Grüneis
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - Alexandre Tkatchenko
- Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Angelos Michaelides
- Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH, United Kingdom
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| |
Collapse
|
28
|
Rishi V, Perera A, Nooijen M, Bartlett RJ. Excited states from modified coupled cluster methods: Are they any better than EOM CCSD? J Chem Phys 2017; 146:144104. [DOI: 10.1063/1.4979078] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Varun Rishi
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
| | - Ajith Perera
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
| | - Marcel Nooijen
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Rodney J. Bartlett
- Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
| |
Collapse
|
29
|
Varsano D, Caprasecca S, Coccia E. Theoretical description of protein field effects on electronic excitations of biological chromophores. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:013002. [PMID: 27830666 DOI: 10.1088/0953-8984/29/1/013002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Photoinitiated phenomena play a crucial role in many living organisms. Plants, algae, and bacteria absorb sunlight to perform photosynthesis, and convert water and carbon dioxide into molecular oxygen and carbohydrates, thus forming the basis for life on Earth. The vision of vertebrates is accomplished in the eye by a protein called rhodopsin, which upon photon absorption performs an ultrafast isomerisation of the retinal chromophore, triggering the signal cascade. Many other biological functions start with the photoexcitation of a protein-embedded pigment, followed by complex processes comprising, for example, electron or excitation energy transfer in photosynthetic complexes. The optical properties of chromophores in living systems are strongly dependent on the interaction with the surrounding environment (nearby protein residues, membrane, water), and the complexity of such interplay is, in most cases, at the origin of the functional diversity of the photoactive proteins. The specific interactions with the environment often lead to a significant shift of the chromophore excitation energies, compared with their absorption in solution or gas phase. The investigation of the optical response of chromophores is generally not straightforward, from both experimental and theoretical standpoints; this is due to the difficulty in understanding diverse behaviours and effects, occurring at different scales, with a single technique. In particular, the role played by ab initio calculations in assisting and guiding experiments, as well as in understanding the physics of photoactive proteins, is fundamental. At the same time, owing to the large size of the systems, more approximate strategies which take into account the environmental effects on the absorption spectra are also of paramount importance. Here we review the recent advances in the first-principle description of electronic and optical properties of biological chromophores embedded in a protein environment. We show their applications on paradigmatic systems, such as the light-harvesting complexes, rhodopsin and green fluorescent protein, emphasising the theoretical frameworks which are of common use in solid state physics, and emerging as promising tools for biomolecular systems.
Collapse
Affiliation(s)
- Daniele Varsano
- S3 Center, CNR Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
| | | | | |
Collapse
|
30
|
Kawasaki A, Sugino O. Four-body correlation embedded in antisymmetrized geminal power wave function. J Chem Phys 2016; 145:244110. [DOI: 10.1063/1.4972991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
31
|
Chu S, Coccia E, Barborini M, Guidoni L. Role of Electron Correlation along the Water Splitting Reaction. J Chem Theory Comput 2016; 12:5803-5810. [DOI: 10.1021/acs.jctc.6b00632] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Shibing Chu
- Dipartimento
di Scienze Fisiche e Chimiche, Università degli studi dell’Aquila, Via Vetoio (Coppito), 67100 L’Aquila, Italy
| | - Emanuele Coccia
- Dipartimento
di Scienze Fisiche e Chimiche, Università degli studi dell’Aquila, Via Vetoio (Coppito), 67100 L’Aquila, Italy
- Sorbonne Universités,
UPMC Univ Paris 06, CNRS, Laboratoire de Chimie Théorique, CC 137-4 place Jussieu, F. 75252 Paris Cedex 05, France
| | | | - Leonardo Guidoni
- Dipartimento
di Scienze Fisiche e Chimiche, Università degli studi dell’Aquila, Via Vetoio (Coppito), 67100 L’Aquila, Italy
| |
Collapse
|
32
|
Barborini M, Sorella S, Rontani M, Corni S. Correlation Effects in Scanning Tunneling Microscopy Images of Molecules Revealed by Quantum Monte Carlo. J Chem Theory Comput 2016; 12:5339-5349. [PMID: 27709944 DOI: 10.1021/acs.jctc.6b00710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Scanning tunneling microscopy (STM) and spectroscopy probe the local density of states of single molecules electrically insulated from the substrate. The experimental images, although usually interpreted in terms of single-particle molecular orbitals, are associated with quasiparticle wave functions dressed by the whole electron-electron interaction. Here we propose an ab initio approach based on quantum Monte Carlo to calculate the quasiparticle wave functions of molecules. Through the comparison between Monte Carlo wave functions and their uncorrelated Hartree-Fock counterparts we visualize the electronic correlation embedded in the simulated STM images, highlighting the many-body features that might be observed.
Collapse
Affiliation(s)
| | - Sandro Sorella
- Scuola Internazionale Superiore di Studi Avanzati (SISSA) and CNR-IOM Democritos National Simulation Center, via Bonomea 265, 34136 Trieste, Italy
| | | | | |
Collapse
|
33
|
Barborini M, Guidoni L. Geometries of low spin states of multi-centre transition metal complexes through extended broken symmetry variational Monte Carlo. J Chem Phys 2016; 145:124107. [DOI: 10.1063/1.4963015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matteo Barborini
- Dipartimento di Ingegneria, Scienze dell’Informazione e Matematica, Università degli studi dell’Aquila, Via Vetoio 2, 67100 Coppito, L’Aquila, Italy
- Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell’Aquila, Via Vetoio 2, 67100 Coppito, L’Aquila, Italy
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell’Aquila, Via Vetoio 2, 67100 Coppito, L’Aquila, Italy
| |
Collapse
|
34
|
Reeves KG, Yao Y, Kanai Y. Diffusion quantum Monte Carlo study of martensitic phase transition energetics: The case of phosphorene. J Chem Phys 2016; 145:124705. [DOI: 10.1063/1.4962759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kyle G. Reeves
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Yi Yao
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Yosuke Kanai
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
35
|
Sinha Ray S, Ghosh A, Chattopadhyay S, Chaudhuri RK. Taming the Electronic Structure of Diradicals through the Window of Computationally Cost Effective Multireference Perturbation Theory. J Phys Chem A 2016; 120:5897-916. [DOI: 10.1021/acs.jpca.6b03211] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Suvonil Sinha Ray
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Anirban Ghosh
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Sudip Chattopadhyay
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Rajat K. Chaudhuri
- Theoretical Physics, Indian Institute of Astrophysics, Bangalore 560034, India
| |
Collapse
|
36
|
Zen A, Coccia E, Gozem S, Olivucci M, Guidoni L. Quantum Monte Carlo Treatment of the Charge Transfer and Diradical Electronic Character in a Retinal Chromophore Minimal Model. J Chem Theory Comput 2016; 11:992-1005. [PMID: 25821414 PMCID: PMC4357234 DOI: 10.1021/ct501122z] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Indexed: 01/22/2023]
Abstract
![]()
The
penta-2,4-dieniminium cation (PSB3) displays similar ground
state and first excited state potential energy features as those of
the retinal protonated Schiff base (RPSB) chromophore in rhodopsin.
Recently, PSB3 has been used to benchmark several electronic structure
methods, including highly correlated multireference wave function
approaches, highlighting the necessity to accurately describe the
electronic correlation in order to obtain reliable properties even
along the ground state (thermal) isomerization paths. In this work,
we apply two quantum Monte Carlo approaches, the variational Monte
Carlo and the lattice regularized diffusion Monte Carlo, to study
the energetics and electronic properties of PSB3 along representative
minimum energy paths and scans related to its thermal cis–trans isomerization. Quantum Monte Carlo
is used in combination with the Jastrow antisymmetrized geminal power
ansatz, which guarantees an accurate and balanced description of the
static electronic correlation thanks to the multiconfigurational nature
of the antisymmetrized geminal power term, and of the dynamical correlation,
due to the presence of the Jastrow factor explicitly depending on
electron–electron distances. Along the two ground state isomerization
minimum energy paths of PSB3, CASSCF calculations yield wave functions
having either charge transfer or diradical character in proximity
of the two transition state configurations. Here, we observe that
at the quantum Monte Carlo level of theory, only the transition state
with charge transfer character can be located. The conical intersection,
which becomes highly sloped, is observed only if the path connecting
the two original CASSCF transition states is extended beyond the diradical
one, namely by increasing the bond-length-alternation (BLA). These
findings are in good agreement with the results obtained by MRCISD+Q
calculations, and they demonstrate the importance of having an accurate
description of the static and dynamical correlation when studying
isomerization and transition states of conjugated systems.
Collapse
|
37
|
Cleland DM, Per MC. Performance of quantum Monte Carlo for calculating molecular bond lengths. J Chem Phys 2016; 144:124108. [DOI: 10.1063/1.4944826] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Deidre M. Cleland
- CSIRO Virtual Nanoscience Laboratory, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Manolo C. Per
- CSIRO Virtual Nanoscience Laboratory, 343 Royal Parade, Parkville, Victoria 3052, Australia
| |
Collapse
|
38
|
Barborini M, Coccia E. Investigating Disjoint Non-Kekulé Diradicals with Quantum Monte Carlo: The Tetramethyleneethane Molecule through the Jastrow Antisymmetrized Geminal Power Wave Function. J Chem Theory Comput 2015; 11:5696-704. [DOI: 10.1021/acs.jctc.5b00819] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matteo Barborini
- S3
Research Center, CNR-NANO, Via Campi 213/a, 41125 Modena, Modena, Italy
| | - Emanuele Coccia
- Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC Univ Paris 06 & CNRS, UMR 7616, F-75005 Paris, France
| |
Collapse
|
39
|
Gryn'ova G, Coote ML, Corminboeuf C. Theory and practice of uncommon molecular electronic configurations. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2015; 5:440-459. [PMID: 27774112 PMCID: PMC5057308 DOI: 10.1002/wcms.1233] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 09/15/2015] [Accepted: 09/17/2015] [Indexed: 11/10/2022]
Abstract
The electronic configuration of the molecule is the foundation of its structure and reactivity. The spin state is one of the key characteristics arising from the ordering of electrons within the molecule's set of orbitals. Organic molecules that have open-shell ground states and interesting physicochemical properties, particularly those influencing their spin alignment, are of immense interest within the up-and-coming field of molecular electronics. In this advanced review, we scrutinize various qualitative rules of orbital occupation and spin alignment, viz., the aufbau principle, Hund's multiplicity rule, and dynamic spin polarization concept, through the prism of quantum mechanics. While such rules hold in selected simple cases, in general the spin state of a system depends on a combination of electronic factors that include Coulomb and Pauli repulsion, nuclear attraction, kinetic energy, orbital relaxation, and static correlation. A number of fascinating chemical systems with spin states that fluctuate between triplet and open-shell singlet, and are responsive to irradiation, pH, and other external stimuli, are highlighted. In addition, we outline a range of organic molecules with intriguing non-aufbau orbital configurations. In such quasi-closed-shell systems, the singly occupied molecular orbital (SOMO) is energetically lower than one or more doubly occupied orbitals. As a result, the SOMO is not affected by electron attachment to or removal from the molecule, and the products of such redox processes are polyradicals. These peculiar species possess attractive conductive and magnetic properties, and a number of them that have already been developed into molecular electronics applications are highlighted in this review. WIREs Comput Mol Sci 2015, 5:440-459. doi: 10.1002/wcms.1233 For further resources related to this article, please visit the WIREs website.
Collapse
Affiliation(s)
- Ganna Gryn'ova
- Institut des Sciences et Ingénierie Chimiques Ecole polytechnique fédérale de Lausanne Lausanne Switzerland
| | - Michelle L Coote
- Australian Research Council Centre of Excellence for Electromaterials Science, Research School of Chemistry Australian National University Canberra Australia
| | - Clemence Corminboeuf
- Institut des Sciences et Ingénierie Chimiques Ecole polytechnique fédérale de Lausanne Lausanne Switzerland
| |
Collapse
|
40
|
Barborini M, Guidoni L. Ground State Geometries of Polyacetylene Chains from Many-Particle Quantum Mechanics. J Chem Theory Comput 2015; 11:4109-18. [PMID: 26405437 PMCID: PMC4570661 DOI: 10.1021/acs.jctc.5b00427] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Indexed: 11/28/2022]
Abstract
Due to the crucial role played by electron correlation, the accurate determination of ground state geometries of π-conjugated molecules is still a challenge for many quantum chemistry methods. Because of the high parallelism of the algorithms and their explicit treatment of electron correlation effects, Quantum Monte Carlo calculations can offer an accurate and reliable description of the electronic states and of the geometries of such systems, competing with traditional quantum chemistry approaches. Here, we report the structural properties of polyacetylene chains H-(C₂H₂)(N)-H up to N = 12 acetylene units, by means of Variational Monte Carlo (VMC) calculations based on the multi-determinant Jastrow Antisymmetrized Geminal Power (JAGP) wave function. This compact ansatz can provide for such systems an accurate description of the dynamical electronic correlation as recently detailed for the 1,3-butadiene molecule [J. Chem. Theory Comput. 2015 11 (2), 508-517]. The calculated Bond Length Alternation (BLA), namely the difference between the single and double carbon bonds, extrapolates, for N → ∞, to a value of 0.0910(7) Å, compatible with the experimental data. An accurate analysis was able to distinguish between the influence of the multi-determinantal AGP expansion and of the Jastrow factor on the geometrical properties of the fragments. Our size-extensive and self-interaction-free results provide new and accurate ab initio references for the structures of the ground state of polyenes.
Collapse
Affiliation(s)
- Matteo Barborini
- Dipartimento
di Ingegneria e Scienze dell’Informazione e Matematica, Università degli studi dell’Aquila, Via Vetoio (Coppito), 67100 L’Aquila, Italy
- Dipartimento
di Scienze Fisiche e Chimiche, Università
degli studi dell’Aquila, Via Vetoio (Coppito), 67100 L’Aquila, Italy
| | - Leonardo Guidoni
- Dipartimento
di Scienze Fisiche e Chimiche, Università
degli studi dell’Aquila, Via Vetoio (Coppito), 67100 L’Aquila, Italy
| |
Collapse
|
41
|
Bytautas L, Scuseria GE, Ruedenberg K. Seniority number description of potential energy surfaces: Symmetric dissociation of water, N2, C2, and Be2. J Chem Phys 2015; 143:094105. [DOI: 10.1063/1.4929904] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Laimutis Bytautas
- Department of Chemistry, Galveston College, 4015 Ave. Q, Galveston, Texas 77550, USA
| | - Gustavo E. Scuseria
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Klaus Ruedenberg
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
42
|
Brunk E, Rothlisberger U. Mixed Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulations of Biological Systems in Ground and Electronically Excited States. Chem Rev 2015; 115:6217-63. [PMID: 25880693 DOI: 10.1021/cr500628b] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Elizabeth Brunk
- †Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.,‡Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, California 94618, United States
| | - Ursula Rothlisberger
- †Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.,§National Competence Center of Research (NCCR) MARVEL-Materials' Revolution: Computational Design and Discovery of Novel Materials, 1015 Lausanne, Switzerland
| |
Collapse
|
43
|
Zen A, Luo Y, Mazzola G, Guidoni L, Sorella S. Ab initio molecular dynamics simulation of liquid water by quantum Monte Carlo. J Chem Phys 2015; 142:144111. [PMID: 25877566 DOI: 10.1063/1.4917171] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Although liquid water is ubiquitous in chemical reactions at roots of life and climate on the earth, the prediction of its properties by high-level ab initio molecular dynamics simulations still represents a formidable task for quantum chemistry. In this article, we present a room temperature simulation of liquid water based on the potential energy surface obtained by a many-body wave function through quantum Monte Carlo (QMC) methods. The simulated properties are in good agreement with recent neutron scattering and X-ray experiments, particularly concerning the position of the oxygen-oxygen peak in the radial distribution function, at variance of previous density functional theory attempts. Given the excellent performances of QMC on large scale supercomputers, this work opens new perspectives for predictive and reliable ab initio simulations of complex chemical systems.
Collapse
Affiliation(s)
- Andrea Zen
- Dipartimento di Fisica, “La Sapienza” - Università di Roma, piazzale Aldo Moro 5, 00185 Rome, Italy
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Ye Luo
- SISSA–International School for Advanced Studies, Via Bonomea 26, 34136 Trieste, Italy
- Democritos Simulation Center CNR–IOM Istituto Officina dei Materiali, 34151 Trieste, Italy
| | - Guglielmo Mazzola
- SISSA–International School for Advanced Studies, Via Bonomea 26, 34136 Trieste, Italy
- Democritos Simulation Center CNR–IOM Istituto Officina dei Materiali, 34151 Trieste, Italy
| | - Leonardo Guidoni
- Dipartimento di Fisica, “La Sapienza” - Università di Roma, piazzale Aldo Moro 5, 00185 Rome, Italy
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’ Aquila, via Vetoio, 67100 L’ Aquila, Italy
| | - Sandro Sorella
- SISSA–International School for Advanced Studies, Via Bonomea 26, 34136 Trieste, Italy
- Democritos Simulation Center CNR–IOM Istituto Officina dei Materiali, 34151 Trieste, Italy
| |
Collapse
|
44
|
Small DW, Sundstrom EJ, Head-Gordon M. A simple way to test for collinearity in spin symmetry broken wave functions: General theory and application to generalized Hartree Fock. J Chem Phys 2015; 142:094112. [DOI: 10.1063/1.4913740] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David W. Small
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Eric J. Sundstrom
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| |
Collapse
|
45
|
Barborini M, Guidoni L. π-Conjugation in trans-1,3-butadiene: static and dynamical electronic correlations described through quantum Monte Carlo. J Chem Theory Comput 2015; 11:508-17. [PMID: 26580909 DOI: 10.1021/ct501157f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We investigate the effects of the static and dynamical electronic correlations on the level of conjugation of the trans-1,3-butadiene molecule through Quantum Monte Carlo methods applied to an Antisymmetrized Geminal Power (AGP) wave function, with a Jastrow factor similar to the Gutzwiller ansatz. The degree of conjugation is measured through the convergence of the structural properties of 1,3-butadiene and in particular of the Bond Length Alternation (BLA), that is the difference between the lengths of the single and double carbon bonds. After verifying the different roles of the Fermionic AGP part of our wave function and of the Jastrow factor in recovering electronic correlation, we study the effects of a constrained Active Space AGP (AGPAS), similar to that used in the Complete Active Space (CAS) representation. Through this AGPAS, we are able to identify the effect of the limited active space on the degree of conjugation, showing that in the limit of infinite active space the structural properties converge exactly to those of the atomic AGP, giving a BLA for 1,3-butadiene around 0.1244(5) Å.
Collapse
Affiliation(s)
- Matteo Barborini
- Dipartimento di Ingegneria e Scienze dell'Informazione e Matematica, Università degli studi dell'Aquila , L'Aquila, Italy.,Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell'Aquila , , L'Aquila, Italy
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell'Aquila , , L'Aquila, Italy
| |
Collapse
|
46
|
Zen A, Trout BL, Guidoni L. Properties of reactive oxygen species by quantum Monte Carlo. J Chem Phys 2014; 141:014305. [DOI: 10.1063/1.4885144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Andrea Zen
- Dipartimento di Fisica, La Sapienza - Università di Roma, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Bernhardt L. Trout
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, Massachusetts 02139, USA
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli studi de L'Aquila, Via Vetoio, 67100 Coppito, L'Aquila, Italy
| |
Collapse
|
47
|
Varsano D, Coccia E, Pulci O, Conte AM, Guidoni L. Ground state structures and electronic excitations of biological chromophores at Quantum Monte Carlo/Many Body Green’s Function Theory level. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
48
|
Giesbertz KJH, van Leeuwen R. Compact two-electron wave function for bond dissociation and Van der Waals interactions: a natural amplitude assessment. J Chem Phys 2014; 140:184108. [PMID: 24832254 DOI: 10.1063/1.4875338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electron correlations in molecules can be divided in short range dynamical correlations, long range Van der Waals type interactions, and near degeneracy static correlations. In this work, we analyze for a one-dimensional model of a two-electron system how these three types of correlations can be incorporated in a simple wave function of restricted functional form consisting of an orbital product multiplied by a single correlation function f (r12) depending on the interelectronic distance r12. Since the three types of correlations mentioned lead to different signatures in terms of the natural orbital (NO) amplitudes in two-electron systems, we make an analysis of the wave function in terms of the NO amplitudes for a model system of a diatomic molecule. In our numerical implementation, we fully optimize the orbitals and the correlation function on a spatial grid without restrictions on their functional form. Due to this particular form of the wave function, we can prove that none of the amplitudes vanishes and moreover that it displays a distinct sign pattern and a series of avoided crossings as a function of the bond distance in agreement with the exact solution. This shows that the wave function ansatz correctly incorporates the long range Van der Waals interactions. We further show that the approximate wave function gives an excellent binding curve and is able to describe static correlations. We show that in order to do this the correlation function f (r12) needs to diverge for large r12 at large internuclear distances while for shorter bond distances it increases as a function of r12 to a maximum value after which it decays exponentially. We further give a physical interpretation of this behavior.
Collapse
Affiliation(s)
- Klaas J H Giesbertz
- Theoretical Chemistry, Faculty of Exact Sciences, VU University, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Robert van Leeuwen
- Department of Physics, Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Survontie 9, Jyväskylä, Finland
| |
Collapse
|