High-throughput ab initio reaction mechanism exploration in the cloud with automated multi-reference validation

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 158(8)

Published: Feb. 7, 2023

Quantum chemical calculations on atomistic systems have evolved into a standard approach to studying molecular matter. These often involve significant amount of manual input and expertise, although most this effort could be automated, which would alleviate the need for expertise in software hardware accessibility. Here, we present AutoRXN workflow, an automated workflow exploratory high-throughput electronic structure systems, (i) density functional theory methods are exploited deliver minimum transition-state structures corresponding energies properties, (ii) coupled cluster then launched optimized provide more accurate energy property estimates, (iii) multi-reference diagnostics evaluated back check results subject them multi-configurational potential cases. All carried out cloud environment support massive computational campaigns. Key features all components autonomy, stability, operator interference. We highlight with example autonomous reaction mechanism exploration mode action homogeneous catalyst asymmetric reduction ketones.

Language: Английский

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SCINE—Software for chemical interaction networks

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(22)

Published: June 10, 2024

The software for chemical interaction networks (SCINE) project aims at pushing the frontier of quantum calculations on molecular structures to a new level. While individual as well simple relations between them have become routine in chemistry, developments pushed field high-throughput calculations. Chemical may be created by search specific properties design attempt, or they can defined set elementary reaction steps that form network. modules SCINE been designed facilitate such studies. features are (i) general applicability applied methodologies ranging from electronic structure (no restriction elements periodic table) microkinetic modeling (with little restrictions molecularity), full modularity so also stand-alone programs exchanged external packages fulfill similar purpose (to increase options computational campaigns and provide alternatives case tasks hard impossible accomplish with certain programs), (ii) high stability autonomous operations control steering an operator easy possible, (iii) embedding into complex heterogeneous environments taken individually context A graphical user interface unites all ensures interoperability. All components made available open source free charge.

Language: Английский

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Organic Reactivity Made Easy and Accurate with Automated Multireference Calculations

ACS Central Science, Journal Year: 2024, Volume and Issue: unknown

Published: March 27, 2024

In organic reactivity studies, quantum chemical calculations play a pivotal role as the foundation of understanding and machine learning model development. While prevalent black-box methods like density functional theory (DFT) coupled-cluster (e.g., CCSD(T)) have significantly advanced our reactivity, they frequently fall short in describing multiconfigurational transition states intermediates. Achieving more accurate description necessitates use multireference methods. However, these not been used at scale due to their often-faulty predictions without expert input. Here, we overcome this deficiency with automated pair-density (MC-PDFT) calculations. We apply method 908 automatically generated reactions. find 68% reactions present significant character which approach often provides and/or efficient than DFT CCSD(T). This work presents first high-throughput application enabled by active space selection algorithms computation electronic correlation MC-PDFT on-top functionals. can be fashion, avoiding inconsistency error both single- cases providing descriptions when needed.

Language: Английский

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Quantum Information-Assisted Complete Active Space Optimization (QICAS)

The Journal of Physical Chemistry Letters, Journal Year: 2023, Volume and Issue: 14(49), P. 11022 - 11029

Published: Dec. 4, 2023

We propose an effective quantum information-assisted complete active space optimization scheme (QICAS). What sets QICAS apart from other correlation-based selection schemes is (i) the use of unique measures information that assess correlation in electronic structures unambiguous and predictive manner (ii) orbital step minimizes discarded by approximation. Equipped with these features, yields, for smaller correlated molecule, optimized orbitals respect to which configuration interaction energy reaches corresponding self-consistent field (CASSCF) within chemical accuracy. For more challenging systems such as chromium dimer, offers excellent starting point CASSCF greatly reducing number iterations required numerical convergence. Accordingly, our study validates a profound empirical conjecture: energetically optimal nonactive spaces are predominantly those contain least entanglement.

Language: Английский

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Calculating the Energy Profile of an Enzymatic Reaction on a Quantum Computer

Journal of Chemical Theory and Computation, Journal Year: 2025, Volume and Issue: unknown

Published: March 31, 2025

Quantum computing (QC) provides a promising avenue for enabling quantum chemistry calculations, which are classically impossible due to computational complexity that increases exponentially with system size. As fully fault-tolerant algorithms and hardware, an exponential speedup is predicted, currently out of reach, recent research efforts have been dedicated developing scaling Noisy Intermediate-Scale (NISQ) devices showcase the practical usefulness such machines. To demonstrate NISQ in field chemistry, we apply our recently developed FAST-VQE algorithm state-of-the-art gate reduction strategy based on propositional satisfiability together standard optimization tools simulation rate-determining proton transfer step CO2 hydration catalyzed by carbonic anhydrase resulting first application device enzymatic reaction. this end, combined classical force simulations mechanical methods computers hybrid calculation approach. The presented technique significantly enhances accuracy capabilities QC-based molecular modeling finally pushes it into compelling realistic applications. framework general can be applied beyond case enzymology.

Language: Английский

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Characterizing Conical Intersections in DNA/RNA Nucleobases with Multiconfigurational Wave Functions of Varying Active Space Size

Journal of Chemical Theory and Computation, Journal Year: 2023, Volume and Issue: 19(22), P. 8258 - 8272

Published: Oct. 26, 2023

We characterize the photochemically relevant conical intersections between lowest-lying accessible electronic excited states of different DNA/RNA nucleobases using Cholesky decomposition-based complete active space self-consistent field (CASSCF) algorithms. benchmark two basis set contractions and several spaces for each nucleobase intersection type, measuring first time how size affects topographies in these systems potential implications may have toward their description photoinduced phenomena. Our results show that are highly sensitive to electron correlation included model: by changing amount (and type) correlated orbitals, vastly change, changes observed do not follow any converging pattern obtained with largest most spaces. Comparison across shows analogous almost all mediating population transfer dark 1nO/Nπ* states, while no similarities "ethylene-like" ascribed mediate ultrafast decay component ground state nucleobases. Basis seems a minor effect, appearing be only purine-based derivatives. rule out structural as key factor classifying intersections, which display identical geometries we highlight instead importance correctly describing involved at crossing points. work careful selection is essential accurately describe therefore adequately account role molecular photochemistry.

Language: Английский

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Chelate Complexes of 3d Transition Metal Ions─A Challenge for Electronic-Structure Methods?

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(11), P. 4545 - 4568

Published: May 28, 2024

Different electronic-structure methods were assessed for their ability to predict two important properties of the industrially relevant chelating agent nitrilotriacetic acid (NTA): its selectivity with respect six different first-row transition metal ions and spin-state energetics complex Fe(III). The investigated encompassed density functional theory (DFT), random phase approximation (RPA), coupled cluster (CC) theory, auxiliary-field quantum Monte Carlo (AFQMC) method, as well complete active space self-consistent field (CASSCF) method respective on-top methods: second-order N-electron valence state perturbation (NEVPT2) multiconfiguration pair-density (MC-PDFT). strategies selecting spaces explored, matrix renormalization group (DMRG) approach was used solve largest spaces. Despite somewhat ambiguous multi-reference diagnostics, most gave relatively good agreement experimental data chemical reactions connected selectivity, which only involved transition-metal complexes in high-spin state. CC yielded highest accuracy followed by range-separated DFT AFQMC. We discussed detail that even higher accuracies can be obtained NEVPT2, under prerequisite consistent along entire reaction selected, not case involving A bigger challenge prediction energetics, additionally lower spin states exhibited larger diagnostics. Conceptually different, typically accurate ranging from via DMRG-NEVPT2 combination large AFQMC agreed is energetically significantly favored over other states. This contrast functionals RPA a smaller stabilization some common MC-PDFT predicting low-spin favorable.

Language: Английский

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Error Control and Automatic Detection of Reference Active Spaces in Many-Body Expanded Full Configuration Interaction

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(32), P. 6806 - 6818

Published: Aug. 5, 2024

We present a wide-reaching revamp of the generalized many-body expanded full configuration interaction (MBE-FCI) method. First, we outline how to automatize selection reference active spaces, whereby inherent bias introduced through manual identification is reduced, also within context traditional complete space methods. Second, allow for use compact orbital clusters as expansion objects, which works circumvent unfavorable scaling with number orbitals included in complementary orbitals. Finally, new algorithm ensuring that expansions can be efficiently terminated while conservatively accounting resulting errors. These developments are all tested on variety molecular systems and different representations illustrate abilities our produce correlation energies predetermined error bounds, significantly broadening overall applicability MBE-FCI

Language: Английский

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Variational Active Space Selection with Multiconfiguration Pair-Density Functional Theory

Journal of Chemical Theory and Computation, Journal Year: 2023, Volume and Issue: 19(22), P. 8118 - 8128

Published: Oct. 31, 2023

The selection of an adequate set active orbitals for modeling strongly correlated electronic states is difficult to automate because it highly dependent on the and molecule interest. Although many approaches have shown some success, no single approach has worked well in all cases. In light this, we present "discrete variational selection" (DVS) space selection, which one generates multiple trial wave functions from a diverse systematically constructed spaces then selects between these variationally. We apply this DVS 207 vertical excitations small-to-medium-sized organic inorganic molecules (with 3 18 atoms) QUESTDB database by (i) constructing various sets through diagonalization parametrized operators (ii) choosing result with lowest average energy among This proves ineffective when variationally selecting using density matrix renormalization group (DMRG) or complete self-consistent field (CASSCF) but able provide good results translated PBE (tPBE) functional multiconfiguration pair-density theory (MC-PDFT). Applying DVS-tPBE state-averaged DMRG functions, obtain mean unsigned error only 0.17 eV hybrid MC-PDFT. matches that our previous benchmark without need filter out poor further orbital optimization following SA-DMRG functions. Furthermore, find robustly effectively select new SA-CASSCF results.

Language: Английский

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Toward an Accurate Black-Box Tool for the Kinetics of Gas-Phase Reactions Involving Barrier-less Elementary Steps

Journal of Chemical Theory and Computation, Journal Year: 2023, Volume and Issue: 19(21), P. 7626 - 7639

Published: Oct. 26, 2023

An enhanced computational protocol has been devised for the accurate characterization of gas-phase barrier-less reactions in framework reaction-path (RP) and variable reaction coordinate variational transition-state theory. In particular, synergistic combination density functional theory Monte Carlo sampling to optimize reactive fluxes led a reliable yet effective workflow. A black-box strategy developed selecting most suited with reference high-level one-dimensional potential. At same time, different descriptions hindered rotations are automatically selected, depending on corresponding harmonic frequencies along RP. The performance new tool is investigated by means two prototypical involving degrees static dynamic correlation, namely, H2S + Cl CH3 CH3. remarkable agreement computed kinetic parameters available experimental data confirms accuracy robustness proposed approach. Together their intrinsic interest, these results also pave way toward systematic investigations elementary steps reliable, user-friendly tool, which can be confidently used nonspecialists.

Language: Английский

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