1
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Bramley GA, Beynon OT, Stishenko PV, Logsdail AJ. The application of QM/MM simulations in heterogeneous catalysis. Phys Chem Chem Phys 2023; 25:6562-6585. [PMID: 36810655 DOI: 10.1039/d2cp04537k] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The QM/MM simulation method is provenly efficient for the simulation of biological systems, where an interplay of extensive environment and delicate local interactions drives a process of interest through a funnel on a complex energy landscape. Recent advances in quantum chemistry and force-field methods present opportunities for the adoption of QM/MM to simulate heterogeneous catalytic processes, and their related systems, where similar intricacies exist on the energy landscape. Herein, the fundamental theoretical considerations for performing QM/MM simulations, and the practical considerations for setting up QM/MM simulations of catalytic systems, are introduced; then, areas of heterogeneous catalysis are explored where QM/MM methods have been most fruitfully applied. The discussion includes simulations performed for adsorption processes in solvent at metallic interfaces, reaction mechanisms within zeolitic systems, nanoparticles, and defect chemistry within ionic solids. We conclude with a perspective on the current state of the field and areas where future opportunities for development and application exist.
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Affiliation(s)
- Gabriel Adrian Bramley
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, CF10 3AT, UK.
| | - Owain Tomos Beynon
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, CF10 3AT, UK.
| | | | - Andrew James Logsdail
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, CF10 3AT, UK.
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2
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Summers TJ, Hemmati R, Miller JE, Agbaglo DA, Cheng Q, DeYonker NJ. Evaluating the active site-substrate interplay between x-ray crystal structure and molecular dynamics in chorismate mutase. J Chem Phys 2023; 158:065101. [PMID: 36792523 DOI: 10.1063/5.0127106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Designing realistic quantum mechanical (QM) models of enzymes is dependent on reliably discerning and modeling residues, solvents, and cofactors important in crafting the active site microenvironment. Interatomic van der Waals contacts have previously demonstrated usefulness toward designing QM-models, but their measured values (and subsequent residue importance rankings) are expected to be influenceable by subtle changes in protein structure. Using chorismate mutase as a case study, this work examines the differences in ligand-residue interatomic contacts between an x-ray crystal structure and structures from a molecular dynamics simulation. Select structures are further analyzed using symmetry adapted perturbation theory to compute ab initio ligand-residue interaction energies. The findings of this study show that ligand-residue interatomic contacts measured for an x-ray crystal structure are not predictive of active site contacts from a sampling of molecular dynamics frames. In addition, the variability in interatomic contacts among structures is not correlated with variability in interaction energies. However, the results spotlight using interaction energies to characterize and rank residue importance in future computational enzymology workflows.
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Affiliation(s)
- Thomas J Summers
- Department of Chemistry, The University of Memphis, 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, USA
| | - Reza Hemmati
- Department of Chemistry, The University of Memphis, 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, USA
| | - Justin E Miller
- Department of Chemistry, The University of Memphis, 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, USA
| | - Donatus A Agbaglo
- Department of Chemistry, The University of Memphis, 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, USA
| | - Qianyi Cheng
- Department of Chemistry, The University of Memphis, 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, USA
| | - Nathan J DeYonker
- Department of Chemistry, The University of Memphis, 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, USA
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3
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Jiang Y, Stull SL, Shao Q, Yang ZJ. Convergence in determining enzyme functional descriptors across Kemp eliminase variants. ELECTRONIC STRUCTURE (BRISTOL, ENGLAND) 2022; 4:044007. [PMID: 37425623 PMCID: PMC10327861 DOI: 10.1088/2516-1075/acad51] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Molecular simulations have been extensively employed to accelerate biocatalytic discoveries. Enzyme functional descriptors derived from molecular simulations have been leveraged to guide the search for beneficial enzyme mutants. However, the ideal active-site region size for computing the descriptors over multiple enzyme variants remains untested. Here, we conducted convergence tests for dynamics-derived and electrostatic descriptors on 18 Kemp eliminase variants across six active-site regions with various boundary distances to the substrate. The tested descriptors include the root-mean-square deviation of the active-site region, the solvent accessible surface area ratio between the substrate and active site, and the projection of the electric field (EF) on the breaking C-H bond. All descriptors were evaluated using molecular mechanics methods. To understand the effects of electronic structure, the EF was also evaluated using quantum mechanics/molecular mechanics methods. The descriptor values were computed for 18 Kemp eliminase variants. Spearman correlation matrices were used to determine the region size condition under which further expansion of the region boundary does not substantially change the ranking of descriptor values. We observed that protein dynamics-derived descriptors, including RMSDactive_site and SASAratio, converge at a distance cutoff of 5 Å from the substrate. The electrostatic descriptor, EFC-H, converges at 6 Å using molecular mechanics methods with truncated enzyme models and 4 Å using quantum mechanics/molecular mechanics methods with whole enzyme model. This study serves as a future reference to determine descriptors for predictive modeling of enzyme engineering.
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Affiliation(s)
- Yaoyukun Jiang
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Sebastian L Stull
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Qianzhen Shao
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
| | - Zhongyue J Yang
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, United States of America
- Data Science Institute, Vanderbilt University, Nashville, TN 37235, United States of America
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, United States of America
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4
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Harder, better, faster, stronger: Large-scale QM and QM/MM for predictive modeling in enzymes and proteins. Curr Opin Struct Biol 2021; 72:9-17. [PMID: 34388673 DOI: 10.1016/j.sbi.2021.07.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/25/2021] [Accepted: 07/05/2021] [Indexed: 11/23/2022]
Abstract
Computational prediction of enzyme mechanism and protein function requires accurate physics-based models and suitable sampling. We discuss recent advances in large-scale quantum mechanical (QM) modeling of biochemical systems that have reduced the cost of high-accuracy models. Tradeoffs between sampling and accuracy have motivated modeling with molecular mechanics (MM) in a multiscale QM/MM or iterative approach. Limitations to both conventional density-functional theory and classical MM force fields remain for describing noncovalent interactions in comparison to experiment or wavefunction theory. Because predictions of enzyme action (i.e. electrostatics), free energy barriers, and mechanisms are sensitive to the protocol and embedding method in QM/MM, convergence tests and systematic methods for quantifying QM-level interactions are a needed, active area of development.
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5
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Summers TJ, Cheng Q, Palma MA, Pham DT, Kelso DK, Webster CE, DeYonker NJ. Cheminformatic quantum mechanical enzyme model design: A catechol-O-methyltransferase case study. Biophys J 2021; 120:3577-3587. [PMID: 34358526 DOI: 10.1016/j.bpj.2021.07.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/26/2021] [Accepted: 07/29/2021] [Indexed: 10/20/2022] Open
Abstract
To accurately simulate the inner workings of an enzyme active site with quantum mechanics (QM), not only must the reactive species be included in the model but also important surrounding residues, solvent, or coenzymes involved in crafting the microenvironment. Our lab has been developing the Residue Interaction Network Residue Selector (RINRUS) toolkit to utilize interatomic contact network information for automated, rational residue selection and QM-cluster model generation. Starting from an x-ray crystal structure of catechol-O-methyltransferase, RINRUS was used to construct a series of QM-cluster models. The reactant, product, and transition state of the methyl transfer reaction were computed for a total of 550 models, and the resulting free energies of activation and reaction were used to evaluate model convergence. RINRUS-designed models with only 200-300 atoms are shown to converge. RINRUS will serve as a cornerstone for improved and automated cheminformatics-based enzyme model design.
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Affiliation(s)
- Thomas J Summers
- Department of Chemistry, The University of Memphis, Memphis, Tennessee
| | - Qianyi Cheng
- Department of Chemistry, The University of Memphis, Memphis, Tennessee
| | - Manuel A Palma
- Department of Chemistry, The University of Memphis, Memphis, Tennessee
| | - Diem-Trang Pham
- Department of Chemistry, The University of Memphis, Memphis, Tennessee; Department of Computer Science, The University of Memphis, Memphis, Tennessee
| | - Dudley K Kelso
- Department of Chemistry, The University of Memphis, Memphis, Tennessee
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi
| | - Nathan J DeYonker
- Department of Chemistry, The University of Memphis, Memphis, Tennessee.
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6
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Mehmood R, Kulik HJ. Both Configuration and QM Region Size Matter: Zinc Stability in QM/MM Models of DNA Methyltransferase. J Chem Theory Comput 2020; 16:3121-3134. [PMID: 32243149 DOI: 10.1021/acs.jctc.0c00153] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Quantum-mechanical/molecular-mechanical (QM/MM) methods are essential to the study of metalloproteins, but the relative importance of sampling and degree of QM treatment in achieving quantitative predictions is poorly understood. We study the relative magnitude of configurational and QM-region sensitivity of energetic and electronic properties in a representative Zn2+ metal binding site of a DNA methyltransferase. To quantify property variations, we analyze snapshots extracted from 250 ns of molecular dynamics simulation. To understand the degree of QM-region sensitivity, we perform analysis using QM regions ranging from a minimal 49-atom region consisting only of the Zn2+ metal and its four coordinating Cys residues up to a 628-atom QM region that includes residues within 12 Å of the metal center. Over the configurations sampled, we observe that illustrative properties (e.g., rigid Zn2+ removal energy) exhibit large fluctuations that are well captured with even minimal QM regions. Nevertheless, for both energetic and electronic properties, we observe a slow approach to asymptotic limits with similarly large changes in absolute values that converge only with larger (ca. 300-atom) QM region sizes. For the smaller QM regions, the electronic description of Zn2+ binding is incomplete: the metal binds too tightly and is too stabilized by the strong electrostatic potential of MM point charges, and the Zn-S bond covalency is overestimated. Overall, this work suggests that efficient sampling with QM/MM in small QM regions is an effective method to explore the influence of enzyme structure on target properties. At the same time, accurate descriptions of electronic and energetic properties require a larger QM region than the minimal metal-coordinating residues in order to converge treatment of both metal-local bonding and the overall electrostatic environment.
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Affiliation(s)
- Rimsha Mehmood
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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7
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Yang Z, Mehmood R, Wang M, Qi HW, Steeves AH, Kulik HJ. Revealing quantum mechanical effects in enzyme catalysis with large-scale electronic structure simulation. REACT CHEM ENG 2019; 4:298-315. [PMID: 31572618 PMCID: PMC6768422 DOI: 10.1039/c8re00213d] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Enzymes have evolved to facilitate challenging reactions at ambient conditions with specificity seldom matched by other catalysts. Computational modeling provides valuable insight into catalytic mechanism, and the large size of enzymes mandates multi-scale, quantum mechanical-molecular mechanical (QM/MM) simulations. Although QM/MM plays an essential role in balancing simulation cost to enable sampling with full QM treatment needed to understand electronic structure in enzyme active sites, the relative importance of these two strategies for understanding enzyme mechanism is not well known. We explore challenges in QM/MM for studying the reactivity and stability of three diverse enzymes: i) Mg2+-dependent catechol O-methyltransferase (COMT), ii) radical enzyme choline trimethylamine lyase (CutC), and iii) DNA methyltransferase (DNMT1), which has structural Zn2+ binding sites. In COMT, strong non-covalent interactions lead to long range coupling of electronic structure properties across the active site, but the more isolated nature of the metallocofactor in DNMT1 leads to faster convergence of some properties. We quantify these effects in COMT by computing covariance matrices of by-residue electronic structure properties during dynamics and along the reaction coordinate. In CutC, we observe spontaneous bond cleavage following initiation events, highlighting the importance of sampling and dynamics. We use electronic structure analysis to quantify the relative importance of CHO and OHO non-covalent interactions in imparting reactivity. These three diverse cases enable us to provide some general recommendations regarding QM/MM simulation of enzymes.
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Affiliation(s)
- Zhongyue Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Rimsha Mehmood
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Mengyi Wang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Helena W. Qi
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Adam H. Steeves
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
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8
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Hou S, Qureshi AH, Wei Z. Atomic Charges in Highly Ionic Diatomic Molecules. ACS OMEGA 2018; 3:17180-17187. [PMID: 31458337 PMCID: PMC6643469 DOI: 10.1021/acsomega.8b02370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/27/2018] [Indexed: 06/10/2023]
Abstract
Atomic charges were investigated as functions of detectable atomic and molecular constants at equilibrium structures. It was found based upon the variation idea that atomic charges in highly ionic molecules can be expressed as a function of molecular dipole moments, polarizabilities of free cations, and polarizabilities of free neutral atoms of the corresponding anions. The function can be given in the form of classical Rittner's relationship (J. Chem. Phys. 1951, 19, 1030). For the ground states of alkali halide molecules, the predicted atomic charges are close to an elementary charge e and the predicted dipole moments are in good agreement with the observed values; for spin-restricted high-ionic systems such as the lowest 9Σ electronic states of BN, AlN, GaN, BP, AlP, GaP, BAs, AlAs, and GaAs molecules, the predicted atomic charges are also near 1e and in good agreement with the results of natural population analysis at MRCI/cc-pvqz and HF/6-311+G(3df) levels. Polarizabilities for the lowest quintet states of B-, Al-, Ga-, N+, P+, and As+ ions were also obtained based upon high-level ab initio computations. Atomic charges from other related methods are also investigated for comparison. The results demonstrate that high-quality atomic charges can be obtained with detectable variables, such as molecular dipole moment, vibrational frequency, as well as polarizabilities of the related free atoms and ions.
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Affiliation(s)
- Shilin Hou
- E-mail: .
Phone: 86-532-6678 6562 (S.H.)
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9
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Kulik HJ. Large-scale QM/MM free energy simulations of enzyme catalysis reveal the influence of charge transfer. Phys Chem Chem Phys 2018; 20:20650-20660. [PMID: 30059109 PMCID: PMC6085747 DOI: 10.1039/c8cp03871f] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hybrid quantum mechanical-molecular mechanical (QM/MM) simulations provide key insights into enzyme structure-function relationships. Numerous studies have demonstrated that large QM regions are needed to systematically converge ground state, zero temperature properties with electrostatic embedding QM/MM. However, it is not well known if ab initio QM/MM free energy simulations have this same dependence, in part due to the hundreds of thousands of energy evaluations required for free energy estimations that in turn limit QM region size. Here, we leverage recent advances in electronic structure efficiency and accuracy to carry out range-separated hybrid density functional theory free energy simulations in a representative methyltransferase. By studying 200 ps of ab initio QM/MM dynamics for each of five QM regions from minimal (64 atoms) to one-sixth of the protein (544 atoms), we identify critical differences between large and small QM region QM/MM in charge transfer between substrates and active site residues as well as in geometric structure and dynamics that coincide with differences in predicted free energy barriers. Distinct geometric and electronic structure features in the largest QM region indicate that important aspects of enzymatic rate enhancement in methyltransferases are identified with large-scale electronic structure.
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Affiliation(s)
- Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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10
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Morgenstern A, Jaszai M, Eberhart ME, Alexandrova AN. Quantified electrostatic preorganization in enzymes using the geometry of the electron charge density. Chem Sci 2017; 8:5010-5018. [PMID: 28970888 PMCID: PMC5612031 DOI: 10.1039/c7sc01301a] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/20/2017] [Indexed: 11/21/2022] Open
Abstract
Electrostatic preorganization is thought to be a principle factor responsible for the impressive catalytic capabilities of enzymes. The full protein structure is believed to facilitate catalysis by exerting a highly specific electrostatic field on the active site. Computationally determining the extent of electrostatic preorganization is a challenging process. We propose using the topology and geometry of the electron charge density in the enzyme's active site to asses the effects of electrostatic preorganization. In support of this approach we study the convergence of features of the charge density as the size of the active site model increases in Histone Deacetylase 8. The magnitude of charge density at critical points and most Bader atomic charges are found to converge quickly as more of the protein is included in the simulation. The exact position of critical points however, is found to converge more slowly and be strongly influenced by the protein residues that are further away from the active site. We conjecture that the positions of critical points are affected through perturbations to the wavefunctions in the active site caused by dipole moments from amino acid residues throughout the protein. We further hypothesize that electrostatic preorganization, from the point of view of charge density, can not be easily understood through the charges on atoms or the nature of the bonding interactions, but through the relative positions of critical points that are known to correlate with reactivity and reaction barriers.
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Affiliation(s)
| | - Matthew Jaszai
- Molecular Theory Group , Colorado School of Mines , USA .
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11
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Karelina M, Kulik HJ. Systematic Quantum Mechanical Region Determination in QM/MM Simulation. J Chem Theory Comput 2017; 13:563-576. [DOI: 10.1021/acs.jctc.6b01049] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Maria Karelina
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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12
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Kulik H, Zhang J, Klinman J, Martínez TJ. How Large Should the QM Region Be in QM/MM Calculations? The Case of Catechol O-Methyltransferase. J Phys Chem B 2016; 120:11381-11394. [PMID: 27704827 PMCID: PMC5108028 DOI: 10.1021/acs.jpcb.6b07814] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/09/2016] [Indexed: 01/29/2023]
Abstract
Hybrid quantum mechanical-molecular mechanical (QM/MM) simulations are widely used in studies of enzymatic catalysis. Until recently, it has been cost prohibitive to determine the asymptotic limit of key energetic and structural properties with respect to increasingly large QM regions. Leveraging recent advances in electronic structure efficiency and accuracy, we investigate catalytic properties in catechol O-methyltransferase, a prototypical methyltransferase critical to human health. Using QM regions ranging in size from reactants-only (64 atoms) to nearly one-third of the entire protein (940 atoms), we show that properties such as the activation energy approach within chemical accuracy of the large-QM asymptotic limits rather slowly, requiring approximately 500-600 atoms if the QM residues are chosen simply by distance from the substrate. This slow approach to asymptotic limit is due to charge transfer from protein residues to the reacting substrates. Our large QM/MM calculations enable identification of charge separation for fragments in the transition state as a key component of enzymatic methyl transfer rate enhancement. We introduce charge shift analysis that reveals the minimum number of protein residues (approximately 11-16 residues or 200-300 atoms for COMT) needed for quantitative agreement with large-QM simulations. The identified residues are not those that would be typically selected using criteria such as chemical intuition or proximity. These results provide a recipe for a more careful determination of QM region sizes in future QM/MM studies of enzymes.
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Affiliation(s)
- Heather
J. Kulik
- Department
of Chemistry and PULSE Institute, Stanford
University, Stanford, California 94305, United States
- SLAC
National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Jianyu Zhang
- Departments
of Chemistry and of Molecular and Cell Biology, and California Institute
for Quantitative Biosciences, University
of California, Berkeley, California 94720, United States
| | - Judith
P. Klinman
- Departments
of Chemistry and of Molecular and Cell Biology, and California Institute
for Quantitative Biosciences, University
of California, Berkeley, California 94720, United States
| | - Todd J. Martínez
- Department
of Chemistry and PULSE Institute, Stanford
University, Stanford, California 94305, United States
- SLAC
National Accelerator Laboratory, Menlo Park, California 94025, United States
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13
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De Vos A, Lejaeghere K, Vanpoucke DEP, Joos JJ, Smet PF, Hemelsoet K. First-Principles Study of Antisite Defect Configurations in ZnGa2O4:Cr Persistent Phosphors. Inorg Chem 2016; 55:2402-12. [DOI: 10.1021/acs.inorgchem.5b02805] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arthur De Vos
- Center
for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde, Belgium
| | - Kurt Lejaeghere
- Center
for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde, Belgium
| | - Danny E. P. Vanpoucke
- Center
for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde, Belgium
- Center for Ordered Materials, Organometallics and Catalysis
(COMOC), Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3), 9000 Ghent, Belgium
| | - Jonas J. Joos
- LumiLab, Department
of Solid State Sciences, Ghent University, Krijgslaan 281 (S1), 9000 Ghent, Belgium
- Center for Nano- and Biophotonics, Ghent University, Sint-Pietersnieuwstraat
41, 9000 Ghent, Belgium
| | - Philippe F. Smet
- LumiLab, Department
of Solid State Sciences, Ghent University, Krijgslaan 281 (S1), 9000 Ghent, Belgium
- Center for Nano- and Biophotonics, Ghent University, Sint-Pietersnieuwstraat
41, 9000 Ghent, Belgium
| | - Karen Hemelsoet
- Center
for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde, Belgium
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14
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Seidler T, Champagne B. Which charge definition for describing the crystal polarizing field and the χ(1) and χ(2) of organic crystals? Phys Chem Chem Phys 2015; 17:19546-56. [DOI: 10.1039/c5cp03248b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Crystal optical susceptibilities are probes to assess the performance of the charge definition employed to describe the crystal polarizing field.
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Affiliation(s)
- Tomasz Seidler
- Laboratoire de Chimie Théorique
- University of Namur
- Namur
- Belgium
- Faculty of Chemistry
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