Transcorrelated methods applied to second row elements

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(6)

Published: Feb. 13, 2025

We explore the applicability of transcorrelated method to elements in second row periodic table. use Hamiltonians conjunction with full configuration interaction quantum Monte Carlo and coupled cluster techniques obtain total energies ionization potentials, investigating their dependence on nature size basis sets used. Transcorrelation accelerates convergence complete set limit relative conventional approaches, chemically accurate results can generally be obtained cc-pVTZ basis, even a frozen Ne core post-Hartree–Fock treatment.

Language: Английский

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Shortcut to chemically accurate quantum computing via density-based basis-set correction

Communications Chemistry, Journal Year: 2024, Volume and Issue: 7(1)

Published: Nov. 18, 2024

Quantum computing promises a computational advantage over classical methods in electronic-structure calculations, with expected applications drug design and materials science. Accessing quantitative description of chemical systems while minimizing quantum resources, such as the number qubits, is an essential challenge given limited capabilities current processors. We provide shortcut towards computations at accuracy by approaching complete-basis-set limit (CBS) through integrating density-functional theory into algorithms via density-based basis-set corrections coupled to basis-sets crafted on-the-fly specifically adapted system/user-defined qubit budget. The approach self-consistently accelerates convergence, improving electronic densities, ground-state energies, first-order properties dipole moments. It can also serve classical, posteriori, energy correction hardware calculations. strategy assessed using GPU-accelerated state-vector emulation up 32 qubits. converge energies four (He, Be, H$_2$, LiH) within CBS full-configuration-interaction reference, offering systematic increase beyond double-zeta quality for various molecules H$_8$ hydrogen chain. obtain dissociation curves H$_2$ LiH that reach whereas challenging simulation N$_2$ triple-bond breaking, we achieve near-triple-zeta cost minimal basis-set. This hybrid allows us results would otherwise require brute-force simulations far more than 100 logical thereby opening opportunities explore real-world chemistry reasonable resources.

Language: Английский

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Computational Chemistry Methods in Cancer Treatment: A Molecular Perspective

Published: Nov. 1, 2024

Despite the rapid advancements in targeted drug therapy cancer treatment over past two decades, resistance remains an issue. Point mutations can often explain emergence of resistance, while other cases, it is not clear why occurs. Furthermore, mechanisms involving physical forces that contribute to binding between and protein are poorly understood. The thesis aims address these questions by using computer models, primarily quantum mechanical methods attempt shed light on occurs leukemia treatment. We have used DFT calculate energies for drugs chronic myeloid (CML) acute (AML),demonstrating asciminib enhances effect nilotinib T315I-mutated CML, thus allowing with ponatinib be avoided. In AML treatment, a combination DFT, MD, NCI, EDA been show mutation R140Q/Q316E trans enzyme IDH2 leads enasidenib. accuracy various exchange-correlation functionals was evaluated against limited dataset, yielding ~ 1.5 kcal/mol, highlighting potential simple models. one study, we were able when dasatinib binds mutated form ABL1 arises due variety factors, just breaking hydrogen bond. has employed analyze dominant at site, extension this method (DFTB-EDA) developed handle larger systems. Using FEP/REMD imatinib proteins analyzed study off-target binding, aim clarifying drugs' toxicity. observed tended overestimate energy, under estimate it. Overall, demonstrates EDA, FEP applicable concrete problems studying CML AML, despite methods.This methodology, however, forms but canbe applied more broadly conditions.

Language: Английский

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Removing Basis Set Incompleteness Error in Finite-Temperature Electronic Structure Calculations: Two-Electron Systems

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(49), P. 10659 - 10672

Published: Nov. 25, 2024

We investigate the basis-set-size dependence for quantities related to interacting electrons in canonical ensemble. Calculations are performed using exact diagonalization (finite temperature full configuration interaction method) on two-electron model systems─the uniform electron gas (UEG) and helium atom. Our data reproduce previous observations of a competition how internal energy converges between ground-state correlation high-temperature kinetic energy. explore this can be component parts including kinetic, exchange, energies show there is surprising nuance broken down into mostly monotonically converging quantities. also that separation free with/without allows monotonic convergence with basis set size due variational principle. find matches previously observed properties discuss divergence happens when finite analytical hydrogen atom complete limit compare large periodic box. Reducing box size, we saw trends were similar UEG.

Language: Английский

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Evaluating Variational Quantum Eigensolver Approaches for Simplified Models of Molecular Systems: A Case Study on Protocatechuic Acid

Molecules, Journal Year: 2024, Volume and Issue: 30(1), P. 119 - 119

Published: Dec. 31, 2024

The Variational Quantum Eigensolver (VQE) is a hybrid algorithm that combines quantum and classical computing to determine the ground-state energy of molecular systems. In this context, study applies VQE investigate ground state protocatechuic acid, analyzing its performance with various Ansatzes active spaces. Subsequently, all results were compared those obtained CISD FCI methods. demonstrate Ansatzes, like Unitary Coupled Cluster Singles Doubles (UCCSD) variations Hardware-Efficient generally achieve accuracy close FCI. conclusion, highlights effectiveness as robust method for investigating energies. Additionally, findings emphasize pivotal role Ansatz design space selection in optimizing performance, offering meaningful insights into capabilities constraints.

Language: Английский

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Variational quantum imaginary time evolution for matrix product state Ansatz with tests on transcorrelated Hamiltonians

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(14)

Published: Oct. 8, 2024

The matrix product state (MPS) Ansatz offers a promising approach for finding the ground of molecular Hamiltonians and solving quantum chemistry problems. Building on this concept, proposed technique circuit MPS (QCMPS) enables simulation chemical systems using relatively small number qubits. In study, we enhance optimization performance QCMPS by employing variational imaginary time evolution (VarQITE) approach. Guided McLachlan's principle, VarQITE method provides analytical metrics gradients, resulting in improved convergence efficiency robustness QCMPS. We validate these improvements numerically through simulations H2, H4, LiH molecules. addition, given that is applicable to non-Hermitian Hamiltonians, evaluate its effectiveness preparing transcorrelated Hamiltonians. This yields energy estimates comparable complete basis set (CBS) limit while even fewer particular, perform beryllium atom molecule only three qubits, maintaining high fidelity with CBS systems. qubit reduction achieved combined advantages both transcorrelation. Our findings demonstrate potential practicality algorithm near-term devices.

Language: Английский

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