Accelerating Quantum Chemistry with Vectorized and Batched Integrals

Huang, Hua; Chow, Edmond

doi:10.1109/sc.2018.00044

Cited by 10 publications

(6 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The QP equations were always solved iteratively (i.e., no linearized approximation was used). All calculations used the Simint library , and a 10 –14 Schwarz screening threshold for the evaluation of the electron repulsion integrals. All CLBEs were obtained using the PBEh functional with 45% of exact exchange as the starting point for the G 0 W 0 calculations, unless explicitly noted otherwise.…”

Section: Computational Detailsmentioning

confidence: 99%

Basis Set Selection for Molecular Core-Level GW Calculations

Mejı́a-Rodrı́guez

Kunitsa

Aprà

et al. 2022

J. Chem. Theory Comput.

View full text Add to dashboard Cite

The GW approximation has been recently gaining popularity among the methods for simulating molecular core-level X-ray photoemission spectra. Traditionally, Gaussian-type orbital GW core-level binding energies have been computed using either the cc-pVnZ or def2-nZVP basis set families, extrapolating the obtained results to the complete basis set limit, followed by an element-specific relativistic correction. Despite achieving rather good accuracy, it has been previously stated that these binding energies are chronically underestimated. In the present work, we show that those previous studies obtained results that were not well-converged with respect to the basis set size and that, once basis set convergence is achieved, there seems to be no such underestimation. Standard techniques known to offer a good cost-accuracy ratio in other theories demonstrate that the cc-pVnZ and def2-nZVP families exhibit contraction errors and might lead to unreliable complete basis set extrapolations for absolute binding energies, often deviating about 200–500 meV from the putative basis set limit found in this work. On the other hand, uncontracted versions of these basis sets offer vastly improved convergence. Even faster convergence can be obtained using core-rich property-optimized basis set families like pcSseg-n, pcJ-n, and ccX-nZ. Finally, we also show that the improvement observed for core properties using these specialized basis sets does not degrade their description of valence excitations: vertical ionization potentials and electron affinities computed with these basis sets converge as fast as the ones obtained with the aug-cc-pVnZ family, thus offering a balanced description of both core and valence regions.

show abstract

Section: Computational Detailsmentioning

confidence: 99%

Basis Set Selection for Molecular Core-Level GW Calculations

Mejı́a-Rodrı́guez

Kunitsa

Aprà

et al. 2022

J. Chem. Theory Comput.

View full text Add to dashboard Cite

show abstract

“…This was obtained by reducing the size of messages injected at one time, both by modifying the NWChem and the Global Arrays source code. We have used the Simint library for the calculation of electron repulsion integral (ERI). , The use of the Simint library proved to be crucial to avoid numerical instability. On top of this, Simint has been written to efficiently use the AVX-512 vector operations available on the Cori KNL hardware.…”

mentioning

confidence: 99%

Guest–Host Interactions in Clathrate Hydrates: Benchmark MP2 and CCSD(T)/CBS Binding Energies of CH₄, CO₂, and H₂S in (H₂O)₂₀Cages

Heindel

Herman

Aprà

et al. 2021

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

We present benchmark binding energies of naturally occurring gas molecules CH 4 , CO 2 , and H 2 S in the small cage, namely, the pentagonal dodecahedron (5 12 ) (H 2 O) 20 , which is one of the constituent cages of the 3 major lattices (structures I, II, and H) of clathrate hydrates. These weak interactions require higher levels of electron correlation and converge slowly with an increasing basis set to the complete basis set (CBS) limit, necessitating the use of large basis sets up to the aug-cc-pV5Z and subsequent correction for basis set superposition error (BSSE). For the host hollow (H 2 O) 20 cages, we have identified a most stable isomer with binding energy of −200.8 ± 2.1 kcal/mol at the CCSD(T)/CBS limit (−199.2 ± 0.5 kcal/mol at the MP2/CBS limit). Additionally, we report converged second order Møller−Plesset (MP2) CBS binding energies for the encapsulation of guests in the (H 2 O) 20 cage of −4.3 ± 0.1 for CH 4 @(H 2 O) 20 , −6.6 ± 0.1 for CO 2 @(H 2 O) 20 , and −8.5 ± 0.1 kcal/mol for H 2 S@(H 2 O) 20 , respectively. For CH 4 @(H 2 O) 20 , exhibiting the weakest encapsulation affinity among the three, we report CCSD(T)/aug-cc-pVTZ binding energies and, based on them, a CCSD(T)/CBS estimate of −4.75 ± 0.1 kcal/mol. To the best of our knowledge, the CCSD(T)/aug-cc-pVTZ calculation for CH 4 @(H 2 O) 20 is the largest one reported to date (168 valence electrons, 1978 basis functions, and the correlation of 84 doubly occupied and 1873 virtual orbitals) and required a scalable implementation of the (T) module on 6144 nodes (350 208 cores) of the "Cori" supercomputer at the National Energy Research Supercomputing Center (NERSC) for a total execution time of 195 min (for the (T) part). These efficient scalable implementations of highly correlated methods offer the capability to obtain long-lasting benchmarks of intermolecular interactions in complex systems. They also provide a path toward parametrizing classical potentials needed to study the dynamical and transport properties in these complex systems as well as assess the accuracy of lower scaling electronic structure methods such as density functional theory (DFT) and MP2 including its spin-biased variants.

show abstract

“…no linearized approximation was used). All calculations used the SIMINT library 32,33 and a 10 −14 Schwarz screening threshold for the evaluation of the electron repulsion integrals. All CLBEs were obtained using the PBEh 34 functional with 45 % of exact exchange as starting point for the G 0 W 0 calculations.…”

Section: Computational Detailsmentioning

confidence: 99%

On the basis set selection for molecular core-level $GW$ calculations

Mejia-Rodriguez,

Kunitsa,

Aprà

et al. 2022

Preprint

View full text Add to dashboard Cite

The GW approximation has been recently gaining popularity among the method for simulating molecular core-level X-ray photoemission spectra. Traditionally, GW core-level binding energies have been computed using either the cc-pVnZ or def2-nZVP basis set families, extrapolating the obtained results to the complete basis set limit, followed by a an elementspecific relativistic correction. Despite of achieving good accuracy, these binding energies are chronically underestimated. By using first-row elements and standard techniques known to offer good cost-accuracy ratio in other theories, we show that the cc-pVnZ and def2-nZVP families show large contraction errors and lead to unreliable complete basis set extrapolations.On the other hand, we demonstrate that uncontracted versions of these basis sets offer vastly improved convergence. Even faster convergence can be obtained using core-rich, propertyoptimized, basis sets families like pcSseg-n, pcJ-n and ccX-nZ. Finally, we also show that the improvement over the core properties does not degrade the calculation of the valence excitations, and thus offer a balanced description of both core and valence regions.

show abstract

Accelerating Quantum Chemistry with Vectorized and Batched Integrals

Cited by 10 publications

References 37 publications

Basis Set Selection for Molecular Core-Level GW Calculations

Basis Set Selection for Molecular Core-Level GW Calculations

Guest–Host Interactions in Clathrate Hydrates: Benchmark MP2 and CCSD(T)/CBS Binding Energies of CH₄, CO₂, and H₂S in (H₂O)₂₀Cages

On the basis set selection for molecular core-level $GW$ calculations

Contact Info

Product

Resources

About

Accelerating Quantum Chemistry with Vectorized and Batched Integrals

Cited by 10 publications

References 37 publications

Basis Set Selection for Molecular Core-Level GW Calculations

Basis Set Selection for Molecular Core-Level GW Calculations

Guest–Host Interactions in Clathrate Hydrates: Benchmark MP2 and CCSD(T)/CBS Binding Energies of CH4, CO2, and H2S in (H2O)20Cages

On the basis set selection for molecular core-level $GW$ calculations

Contact Info

Product

Resources

About

Guest–Host Interactions in Clathrate Hydrates: Benchmark MP2 and CCSD(T)/CBS Binding Energies of CH₄, CO₂, and H₂S in (H₂O)₂₀Cages