1
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Tiihonen J, Kent PRC, Krogel JT. Surrogate Hessian accelerated structural optimization for stochastic electronic structure theories. J Chem Phys 2022; 156:054104. [DOI: 10.1063/5.0079046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Juha Tiihonen
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Paul R. C. Kent
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Tennessee 37831, USA
| | - Jaron T. Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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2
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Tiihonen J, Clay RC, Krogel JT. Toward quantum Monte Carlo forces on heavier ions: Scaling properties. J Chem Phys 2021; 154:204111. [PMID: 34241166 DOI: 10.1063/5.0052266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantum Monte Carlo (QMC) forces have been studied extensively in recent decades because of their importance with spectroscopic observables and geometry optimization. Here, we benchmark the accuracy and computational cost of QMC forces. The zero-variance zero-bias (ZVZB) force estimator is used in standard variational and diffusion Monte Carlo simulations with mean-field based trial wavefunctions and atomic pseudopotentials. Statistical force uncertainties are obtained with a recently developed regression technique for heavy tailed QMC data [P. Lopez Rios and G. J. Conduit, Phys. Rev. E 99, 063312 (2019)]. By considering selected atoms and dimers with elements ranging from H to Zn (1 ≤ Zeff ≤ 20), we assess the accuracy and the computational cost of ZVZB forces as the effective pseudopotential valence charge, Zeff, increases. We find that the costs of QMC energies and forces approximately follow simple power laws in Zeff. The force uncertainty grows more rapidly, leading to a best case cost scaling relationship of approximately Zeff 6.5(3) for diffusion Monte Carlo. We find that the accessible system size at fixed computational cost scales as Zeff -2, insensitive to model assumptions or the use of the "space warp" variance-reduction technique. Our results predict the practical cost of obtaining forces for a range of materials, such as transition metal oxides where QMC forces have yet to be applied, and underscore the importance of further developing force variance-reduction techniques, particularly for atoms with high Zeff.
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Affiliation(s)
- Juha Tiihonen
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Raymond C Clay
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Jaron T Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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3
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Qu Z, Ma Y. Variational Multistate Density Functional Theory for a Balanced Treatment of Static and Dynamic Correlations. J Chem Theory Comput 2020; 16:4912-4922. [PMID: 32672966 DOI: 10.1021/acs.jctc.0c00208] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Here, an approach to variational multistate density functional theory (vMSDFT) is explored. In this approach, the Kohn-Sham orbitals as well as configuration coefficients were simultaneously optimized, thus yielding a full variational minimum. Furthermore, this work also proposes two important improvements on the MSDFT framework. First, a "point-to-point correction" is used to correct the static correlation present in the DFT framework. Therefore, double counting of static correlation in vMSDFT is mitigated. Second, a general form to construct the transition density functional in the vMSDFT framework is proposed, which allows for the properties of vMSDFT wave functions to be standardized to the complete active space self-consistent field properties. The utility of vMSDFT is illustrated on molecular systems of interest including bond breaking, diradicals, excited states, and conical intersections. The numerical results suggest that the accuracy of vMSDFT is in close agreement with the high-level multireference methods.
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Affiliation(s)
- Zexing Qu
- Institute of Theoretical Chemistry and Laboratory of Theoretical & Computational Chemistry, Jilin University, Changchun 130023, China
| | - Yingjin Ma
- Computer Network Information Center, Chinese Academy of Sciences, Beijing 100190, China.,Center of Scientific Computing Applications & Research, Chinese Academy of Sciences, Beijing 100190, China
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4
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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
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5
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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]
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6
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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
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7
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Szefczyk B, Grabarek D, Walczak E, Andruniów T. Excited-state minima and emission energies of retinal chromophore analogues: Performance of CASSCF and CC2 methods as compared with CASPT2. J Comput Chem 2017; 38:1799-1810. [PMID: 28512740 DOI: 10.1002/jcc.24821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/10/2017] [Accepted: 04/13/2017] [Indexed: 11/08/2022]
Abstract
This study provides gas-phase S1 excited-state geometries along with emission and adiabatic energies for methylated/demethylated and ring-locked analogues of protonated Schiff base retinal models comprising system of five conjugated double bonds (PSB5), using second order multiconfiguration perturbation theory (CASPT2). CASPT2 results serve as reference data to assess the performance of CC2 (second-order approximate coupled cluster singles and doubles) and a commonly used CASSCF/CASPT2 protocol, that is, complete active space self-consistent field (CASSCF) geometry optimization followed by CASPT2 energy calculation. We find that the CASSCF methodology fails to locate planar S1 minimum energy structures for four out of five investigated planar models in contrast to CC2 and CASPT2 methods. However, for those which were found: one planar and two twisted minima, there is an excellent agreement between CASSCF and CASPT2 results in terms of geometrical parameters, one-electron properties, as well as emission and adiabatic energies. CC2 performs well for in-plane S1 minima and their spectroscopic and electronic properties. However, this picture deteriorates for twisted minima. As expected, the CC2 description of the S2 electronic state, with strong multireference and significant double excitation character, is very poor, exhibiting errors in transition energies exceeding 1 eV. They may be substantially diminished by recalculating transition energies with CASPT2 method. Our work shows that CASSCF/CASPT2 and CC2 shortcomings may influence gas-phase retinal analogues' excited state description in a dramatic way. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Borys Szefczyk
- Advanced Materials Engineering and Modelling Group, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, Wroclaw, 50-370, Poland
| | - Dawid Grabarek
- Advanced Materials Engineering and Modelling Group, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, Wroclaw, 50-370, Poland
| | - Elżbieta Walczak
- Advanced Materials Engineering and Modelling Group, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, Wroclaw, 50-370, Poland
| | - Tadeusz Andruniów
- Advanced Materials Engineering and Modelling Group, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, Wroclaw, 50-370, Poland
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8
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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.
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Affiliation(s)
- Daniele Varsano
- S3 Center, CNR Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
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9
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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
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10
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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
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11
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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.
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12
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Grabarek D, Walczak E, Andruniów T. Assessing the Accuracy of Various Ab Initio Methods for Geometries and Excitation Energies of Retinal Chromophore Minimal Model by Comparison with CASPT3 Results. J Chem Theory Comput 2016; 12:2346-56. [DOI: 10.1021/acs.jctc.6b00108] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dawid Grabarek
- Advanced Materials Engineering
and Modelling Group, Wroclaw University of Technology, Wyb. Wyspianskiego
27, 50-370 Wroclaw, Poland
| | - Elżbieta Walczak
- Advanced Materials Engineering
and Modelling Group, Wroclaw University of Technology, Wyb. Wyspianskiego
27, 50-370 Wroclaw, Poland
| | - Tadeusz Andruniów
- Advanced Materials Engineering
and Modelling Group, Wroclaw University of Technology, Wyb. Wyspianskiego
27, 50-370 Wroclaw, Poland
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13
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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.
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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
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14
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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
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15
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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]
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16
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Zen A, Coccia E, Luo Y, Sorella S, Guidoni L. Static and Dynamical Correlation in Diradical Molecules by Quantum Monte Carlo Using the Jastrow Antisymmetrized Geminal Power Ansatz. J Chem Theory Comput 2014; 10:1048-61. [DOI: 10.1021/ct401008s] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Andrea Zen
- Dipartimento
di Fisica, Sapienza-Università di Roma, Piazzale Aldo Moro
5, 00185 Rome, Italy
| | - Emanuele Coccia
- Dipartimento
di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, Via Vetoio 2, 67010 L’Aquila, Italy
| | - Ye Luo
- Scuola
Internazionale Superiore di Studi Avanzati (SISSA) and Democritos
National Simulation Center, Istituto Officina dei Materiali del CNR, via Bonomea 265, 34136 Trieste, Italy
| | - Sandro Sorella
- Scuola
Internazionale Superiore di Studi Avanzati (SISSA) and Democritos
National Simulation Center, Istituto Officina dei Materiali del CNR, via Bonomea 265, 34136 Trieste, Italy
| | - Leonardo Guidoni
- Dipartimento
di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, Via Vetoio 2, 67010 L’Aquila, Italy
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17
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Coccia E, Varsano D, Guidoni L. Ab Initio Geometry and Bright Excitation of Carotenoids: Quantum Monte Carlo and Many Body Green's Function Theory Calculations on Peridinin. J Chem Theory Comput 2014; 10:501-6. [PMID: 26580027 PMCID: PMC4864508 DOI: 10.1021/ct400943a] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this letter, we report the singlet ground state structure of the full carotenoid peridinin by means of variational Monte Carlo (VMC) calculations. The VMC relaxed geometry has an average bond length alternation of 0.1165(10) Å, larger than the values obtained by DFT (PBE, B3LYP, and CAM-B3LYP) and shorter than that calculated at the Hartree-Fock (HF) level. TDDFT and EOM-CCSD calculations on a reduced peridinin model confirm the HOMO-LUMO major contribution of the Bu(+)-like (S2) bright excited state. Many Body Green's Function Theory (MBGFT) calculations of the vertical excitation energy of the Bu(+)-like state for the VMC structure (VMC/MBGFT) provide an excitation energy of 2.62 eV, in agreement with experimental results in n-hexane (2.72 eV). The dependence of the excitation energy on the bond length alternation in the MBGFT and TDDFT calculations with different functionals is discussed.
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Affiliation(s)
- Emanuele Coccia
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, via Vetoio, 67110 L’Aquila, Italy
| | - Daniele Varsano
- S3 Center, CNR Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, via Vetoio, 67110 L’Aquila, Italy
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18
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Varsano D, Barborini M, Guidoni L. Kohn-Sham orbitals and potentials from quantum Monte Carlo molecular densities. J Chem Phys 2014; 140:054102. [DOI: 10.1063/1.4863213] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Zen A, Luo Y, Sorella S, Guidoni L. Molecular Properties by Quantum Monte Carlo: An Investigation on the Role of the Wave Function Ansatz and the Basis Set in the Water Molecule. J Chem Theory Comput 2013; 9:4332-4350. [PMID: 24526929 PMCID: PMC3920371 DOI: 10.1021/ct400382m] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Quantum Monte Carlo methods are accurate and promising many body techniques for electronic structure calculations which, in the last years, are encountering a growing interest thanks to their favorable scaling with the system size and their efficient parallelization, particularly suited for the modern high performance computing facilities. The ansatz of the wave function and its variational flexibility are crucial points for both the accurate description of molecular properties and the capabilities of the method to tackle large systems. In this paper, we extensively analyze, using different variational ansatzes, several properties of the water molecule, namely, the total energy, the dipole and quadrupole momenta, the ionization and atomization energies, the equilibrium configuration, and the harmonic and fundamental frequencies of vibration. The investigation mainly focuses on variational Monte Carlo calculations, although several lattice regularized diffusion Monte Carlo calculations are also reported. Through a systematic study, we provide a useful guide to the choice of the wave function, the pseudopotential, and the basis set for QMC calculations. We also introduce a new method for the computation of forces with finite variance on open systems and a new strategy for the definition of the atomic orbitals involved in the Jastrow-Antisymmetrised Geminal power wave function, in order to drastically reduce the number of variational parameters. This scheme significantly improves the efficiency of QMC energy minimization in case of large basis sets.
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Affiliation(s)
- Andrea Zen
- Dipartimento di Fisica, La Sapienza—Università di Roma, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Ye Luo
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
| | - Sandro Sorella
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli studi de L’Aquila, Via Vetoio, 67100 Coppito, L’Aquila, Italy
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20
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Hernández-Rodríguez EW, Montero-Alejo AL, López R, Sánchez-García E, Montero-Cabrera LA, García de la Vega JM. Electron density deformations provide new insights into the spectral shift of rhodopsins. J Comput Chem 2013; 34:2460-71. [DOI: 10.1002/jcc.23414] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/26/2013] [Accepted: 07/27/2013] [Indexed: 11/08/2022]
Affiliation(s)
| | - Ana Lilian Montero-Alejo
- Laboratorio de Química Computacional y Teórica; Departamento de Química Física; Universidad de La Habana; Havana; 10400; Cuba
| | - Rafael López
- Departamento de Química Física Aplicada; Facultad de Ciencias, Universidad Autónoma de Madrid; Madrid; 28049; Spain
| | - Elsa Sánchez-García
- Max-Planck-Institut für Kohlenforschung; Kaiser-Wilhelm-Platz 1; Mülheim an der Ruhr; 45470; Germany
| | - Luis Alberto Montero-Cabrera
- Laboratorio de Química Computacional y Teórica; Departamento de Química Física; Universidad de La Habana; Havana; 10400; Cuba
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21
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Coccia E, Varsano D, Guidoni L. Protein Field Effect on the Dark State of 11- cis Retinal in Rhodopsin by Quantum Monte Carlo/Molecular Mechanics. J Chem Theory Comput 2013; 9:8-12. [PMID: 24611033 PMCID: PMC3943175 DOI: 10.1021/ct3007502] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The accurate determination of the geometrical details of the dark state of 11-cis retinal in rhodopsin represents a fundamental step for the rationalization of the protein role in the optical spectral tuning in the vision mechanism. We have calculated geometries of the full retinal protonated Schiff base chromophore in the gas phase and in the protein environment using the correlated variational Monte Carlo method. The bond length alternation of the conjugated carbon chain of the chromophore in the gas phase shows a significant reduction when moving from the β-ionone ring to the nitrogen, whereas, as expected, the protein environment reduces the electronic conjugation. The proposed dark state structure is fully compatible with solid-state NMR data reported by Carravetta et al. [J. Am. Chem. Soc. 2004, 126, 3948-3953]. TDDFT/B3LYP calculations on such geometries show a blue opsin shift of 0.28 and 0.24 eV induced by the protein for S1 and S2 states, consistently with literature spectroscopic data. The effect of the geometrical distortion alone is a red shift of 0.21 and 0.16 eV with respect to the optimized gas phase chromophore. Our results open new perspectives for the study of the properties of chromophores in their biological environment using correlated methods.
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Affiliation(s)
- Emanuele Coccia
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, via Vetoio, 67100, L’Aquila, Italy
| | - Daniele Varsano
- Dipartimento di Fisica, “Sapienza” - Università di Roma, piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, via Vetoio, 67100, L’Aquila, Italy
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22
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Barborini M, Guidoni L. Reaction pathways by quantum Monte Carlo: insight on the torsion barrier of 1,3-butadiene, and the conrotatory ring opening of cyclobutene. J Chem Phys 2012; 137:224309. [PMID: 23249005 PMCID: PMC3925821 DOI: 10.1063/1.4769791] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantum Monte Carlo (QMC) methods are used to investigate the intramolecular reaction pathways of 1,3-butadiene. The ground state geometries of the three conformers s-trans, s-cis, and gauche, as well as the cyclobutene structure are fully optimised at the variational Monte Carlo (VMC) level, obtaining an excellent agreement with the experimental results and other quantum chemistry high level calculations. Transition state geometries are also estimated at the VMC level for the s-trans to gauche torsion barrier of 1,3-butadiene and for the conrotatory ring opening of cyclobutene to the gauche-1,3-butadiene conformer. The energies of the conformers and the reaction barriers are calculated at both variational and diffusional Monte Carlo levels providing a precise picture of the potential energy surface of 1,3-butadiene and supporting one of the two model profiles recently obtained by Raman spectroscopy [Boopalachandran et al., J. Phys. Chem. A 115, 8920 (2011)]. Considering the good scaling of QMC techniques with the system's size, our results also demonstrate how variational Monte Carlo calculations can be applied in the future to properly investigate the reaction pathways of large and correlated molecular systems.
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Affiliation(s)
- Matteo Barborini
- Dipartimento di Matematica Pura ed Applicata, Università degli studi dell'Aquila, via Vetoio (Coppito 2), 67100 L'Aquila, Italy
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23
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Gozem S, Krylov AI, Olivucci M. Conical Intersection and Potential Energy Surface Features of a Model Retinal Chromophore: Comparison of EOM-CC and Multireference Methods. J Chem Theory Comput 2012; 9:284-92. [DOI: 10.1021/ct300759z] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Samer Gozem
- Department of Chemistry, Bowling
Green State University, Bowling Green, Ohio 43403, United States
| | - Anna I. Krylov
- Department of Chemistry, University
of Southern California, Los Angeles, California 90089-0482, United
States
| | - Massimo Olivucci
- Department of Chemistry, Bowling
Green State University, Bowling Green, Ohio 43403, United States
- Dipartimento di Chimica,
Università
di Siena, via De Gasperi 2, I-53100 Siena, Italy
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24
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Zen A, Zhelyazov D, Guidoni L. Optimized Structure and Vibrational Properties by Error Affected Potential Energy Surfaces. J Chem Theory Comput 2012; 8:4204-4215. [PMID: 24093004 DOI: 10.1021/ct300576n] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The precise theoretical determination of the geometrical parameters of molecules at the minima of their potential energy surface and of the corresponding vibrational properties are of fundamental importance for the interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo techniques are correlated electronic structure methods promising for large molecules, which are intrinsically affected by stochastic errors on both energy and force calculations, making the mentioned calculations more challenging with respect to other more traditional quantum chemistry tools. To circumvent this drawback in the present work, we formulate the general problem of evaluating the molecular equilibrium structures, the harmonic frequencies, and the anharmonic coefficients of an error affected potential energy surface. The proposed approach, based on a multidimensional fitting procedure, is illustrated together with a critical evaluation of systematic and statistical errors. We observe that the use of forces instead of energies in the fitting procedure reduces the statistical uncertainty of the vibrational parameters by 1 order of magnitude. Preliminary results based on variational Monte Carlo calculations on the water molecule demonstrate the possibility to evaluate geometrical parameters and harmonic and anharmonic coefficients at this level of theory with an affordable computational cost and a small stochastic uncertainty (<0.07% for geometries and <0.7% for vibrational properties).
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Affiliation(s)
- Andrea Zen
- Dipartimento di Fisica, La Sapienza-Università di Roma, P.le Aldo Moro 2, 00185 Roma, Italy
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