A5058939274- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Strong Light-Matter Interactions
- X-ray Spectroscopy and Fluorescence Analysis
- Catalytic Processes in Materials Science
- Cold Atom Physics and Bose-Einstein Condensates
- Electron and X-Ray Spectroscopy Techniques
- Various Chemistry Research Topics
- Photochemistry and Electron Transfer Studies
- Mass Spectrometry Techniques and Applications
- Atmospheric chemistry and aerosols
- History and advancements in chemistry
- Scientific Computing and Data Management
- CO2 Reduction Techniques and Catalysts
- Quantum, superfluid, helium dynamics
- Machine Learning in Materials Science
- Semiconductor Quantum Structures and Devices
- Electrostatics and Colloid Interactions
- Advanced Data Storage Technologies
- Molecular spectroscopy and chirality
- Crystallography and molecular interactions
- Quantum optics and atomic interactions
- Membrane Separation and Gas Transport
- Advanced Biosensing Techniques and Applications
- Analytical chemistry methods development
Flatiron Health (United States)
2025
Lawrence Berkeley National Laboratory
2021-2024
University of California, Berkeley
2021-2024
Center for Theoretical Biological Physics
2022
Instituto de Aeronáutica e Espaço
2018
Instituto Tecnológico de Aeronáutica
2014-2018
Psi4NumPy demonstrates the use of efficient computational kernels from open-source Psi4 program through popular NumPy library for linear algebra in Python to facilitate rapid development clear, understandable computer code new quantum chemical methods, while maintaining a relatively low execution time. Using these tools, reference implementations have been created number including self-consistent field (SCF), SCF response, many-body perturbation theory, coupled-cluster configuration...
Core-level spectra of 1s electrons elements heavier than Ne show significant relativistic effects. We combine advances in orbital-optimized density functional theory (OO-DFT) with the spin-free exact two-component (X2C) model for scalar effects to study K-edge third period elements. OO-DFT/X2C is found be quite accurate at predicting energies, yielding a ∼0.5 eV root-mean-square error versus experiment modern SCAN (and related) functionals. This marks improvement over >50 deviations that are...
The lack of particle-hole attraction and orbital relaxation within time-dependent density functional theory (TDDFT) lead to extreme errors in the prediction K-edge X-ray absorption spectra (XAS). We derive a linear-response formalism that uses optimized orbitals n - 1-electron system as reference, building proper hole into initial density. Our approach is an exact generalization static-exchange approximation ameliorates interaction error associated with adiabatic reduces TDDFT XAS by orders...
We investigate the use of orbital-optimized references in conjunction with single-reference coupled-cluster theory single and double substitutions (CCSD) for study core excitations ionizations 18 small organic molecules, without response or equation-of-motion (EOM) formalisms. Three schemes are employed to successfully address convergence difficulties associated equations, spin contamination resulting from a symmetry-broken reference, case excitations. In order gauge inherent potential...
<div> <p><i>Psi4NumPy</i> demonstrates the use of efficient computational kernels from open- source <i>Psi4</i> program through popular <i>NumPy</i> library for linear algebra in Python to facilitate rapid development clear, understandable computer code new quantum chemical methods, while maintaining a relatively low execution time. Using these tools, reference implementations have been created number including self-consistent field (SCF), SCF...
Simulating solids with quantum chemistry methods and Gaussian-type orbitals (GTOs) has been gaining popularity. Nonetheless, there are few systematic studies that assess the basis set incompleteness error (BSIE) in these GTO-based simulations over a variety of solids. In this work, we report implementation for solids, apply it to address convergence issue. We employ simple strategy generate large uncontracted (unc) GTO sets, call unc-def2-GTH sets. These sets exhibit improvement towards...
The pseudopotential (PP) approximation is one of the most common techniques in computational chemistry. Despite its long history, development custom PPs has not tracked with explosion different density functional approximations (DFAs). As a result, use exchange/correlation models for which they were developed widespread, although this practice known to be theoretically unsound. extent PP inconsistency errors (PPIEs) associated been systematically explored across types energy differences...
We present a generalization of the phaseless auxiliary-field quantum Monte Carlo (AFQMC) method to cavity quantum-electrodynamical (QED) matter systems. The can be formulated in both Coulomb and dipole gauge. verify its accuracy by benchmarking calculations on set small molecules against full configuration interaction state-of-the-art QED coupled cluster (QED–CCSD) calculations. Our results show that (i) gauge invariance achieved within correlation-consistent Gaussian basis sets, (ii)...
We introduce an electron-photon exchange-correlation functional for quantum electrodynamical density-functional theory (QEDFT). The approach, photon MBD (pMBD), is inspired by the many-body dispersion (MBD) method weak intermolecular interactions, which generalized to include both electronic and photonic (electromagnetic) degrees of freedom on same footing. demonstrate that pMBD accurately captures effects arise in context strong light-matter such as anisotropic beyond single-photon effects,...
The reaction system formed by the methanethiol molecule (CH3SH) and a hydrogen atom was studied via three elementary reactions, two abstractions C–S bond cleavage (CH3SH + H → CH3S H2 (R1); CH2SH (R2); CH3 H2S (R3)). stable structures were optimized with various methodologies of density functional theory MP2 method. Two minimum energy paths for each built using BB1K methodologies, electronic properties on reactants, products, saddle points improved coupled cluster single, double, connected...
We introduce an electron-photon exchange-correlation functional for quantum electrodynamical density-functional theory (QEDFT). The approach, photon MBD (pMBD), is inspired by the many-body dispersion (MBD) method weak intermolecular interactions, which generalized to include both electronic and photonic (electromagnetic) degrees of freedom on same footing. demonstrate that pMBD accurately captures effects arise in context strong light-matter such as anisotropic beyond single-photon effects,...
Accurate simulation of electronic excitations and deexcitations are critical for complementing complex spectroscopic experiments can provide validation to theoretical approaches. Using a generalized framework, we contrast the accuracy validity orbital-constrained linear-response approaches that build upon Kohn-Sham density functional theory (DFT) simulate emission spectra origin propose an efficient approximation, named many-body x-ray spectroscopy or MBXES, simulating such processes. We...
Membrane-based gas separation technology is of crucial importance in the current economy and nanoporous graphene, given its single-atomic layer, an essential building-block material to achieve efficiency towards permeability selectivity for such processes. Classically, pore size main feature that governs diffusion energy barrier. Its nature, nevertheless, also affected by other non-negligible physical mechanisms not yet discussed. Here we propose a theoretical study on role non-covalent...
We present a generalization of the phaseless auxiliary-field quantum Monte Carlo (AFQMC) method to cavity quantum-electrodynamical (QED) matter systems. The can be formulated in both Coulomb and dipole gauge. verify its accuracy by benchmarking calculations on set small molecules against full configuration interaction state-of-the-art QED coupled cluster (QED-CCSD) calculations. Our results show that (i) gauge invariance achieved within correlation-consistent Gaussian basis sets, (ii)...
L\"owdin's symmetry dilemma is an ubiquitous issue in approximate quantum chemistry. In the context of Hartree-Fock (HF) theory, use Slater determinants with some imposed constraints to preserve symmetries exact problem may lead physically unreasonable potential energy surfaces. On other hand, lifting these leads so-called broken solutions that usually provide better energetics, at cost losing information about good numbers describe state system. This behavior has been previously extensively...
X-ray photoelectron spectroscopy (XPS) is a powerful characterization technique that unveils subtle chemical environment differences via core–electron binding energy (CEBE) analysis. We extend the development of real-space pseudopotential methods to calculating 1s, 2s, and 2p3/2 CEBEs third-row elements (S, P, Si) within framework Kohn–Sham density-functional theory (KS-DFT). The new approach systematically prevents variational collapse simplifies core-excited orbital selection dense level...
Psi4NumPy demonstrates the use of efficient computational kernels from open- source Psi4 program through popular NumPy library for linear algebra in Python to facilitate rapid development clear, understandable computer code new quantum chemical methods, while maintaining a relatively low execution time. Using these tools, reference implementations have been created number including self-consistent field (SCF), SCF response, many-body perturbation theory, coupled-cluster configuration...
Chemical bond plays a central role in the description of physicochemical properties molecules and solids it is essential to several fields science engineering, governing material’s mechanical, electrical, catalytic optoelectronic properties, among others. Due this indisputable importance, proper chemical needed, commonly obtained through solving Schrödinger equation system with either molecular orbital theory (molecules) or band (solids). However, connecting these seemingly different...
<p>Chemical bond plays a central role in the description of physicochemical properties molecules and solids it is essential to several fields science engineering, governing material’s mechanical, electrical, catalytic optoelectronic properties, among others. Due this indisputable importance, proper chemical needed, commonly obtained through solving Schrödinger equation system with either molecular orbital theory (molecules) or band (solids). However, connecting these seemingly...
The particle-hole interaction problem is longstanding within time-dependent density functional theory (TDDFT) and leads to extreme errors in the prediction of K-edge X-ray absorption spectra (XAS). We derive a linear-response formalism that uses optimized orbitals n-1-electron system as reference, building orbital relaxation proper hole into initial density. Our approach an exact generalization static-exchange approximation ameliorates error associated with adiabatic reduces TDDFT XAS by...
We investigate the use of orbital-optimized references in conjunction with single-reference coupled-cluster theory single and double substitutions (CCSD) for study core excitations ionizations 18 small organic molecules, without any response or equation-of-motion formalisms. Three schemes are employed to successfully address convergence difficulties associated equations, spin contamination resulting from a symmetry-broken reference, case excitations. In order gauge inherent potential methods...