21 research outputs found
Laplace-Transform GW
We present a simple and accurate GW implementation based on a combination of
a Laplace transformation (LT) and other acceleration techniques used in
post-SCF quantum chemistry, namely, natural auxiliary functions and the
frozen-core approximation. The LT-GW approach combines three major benefits:
(a) a small prefactor for the computational scaling, (b) easy integration into
existing molecular GW implementations, and (c) significant performance
improvements for a wide range of possible applications. Illustrating these
advantages for systems consisting of up to 352 atoms and 7412 basis functions,
we further demonstrate the benefits of this approach combined with an efficient
implementation of the Bethe-Salpeter equation
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Massively Parallel Fragment-Based Quantum Chemistry for Large Molecular Systems: The Serestipy Software
We describe the Serestipy software, which is an add-on to the quantum-chemistry program Serenity. Serestipy is a representational-state transfer-oriented application programming interface written in the Python programming language enabling parallel subsystem density-functional theory calculations. We introduce approximate strategies in the context of frozen-density embedding time-dependent density-functional theory to make parallel large-scale excited-state calculations feasible. Their accuracy is carefully benchmarked with calculations for large assemblies of porphine molecules. We apply this framework to a theoretical model nanotube consisting of rings of porphine monomers, with 12,160 atoms (or 264,960 basis functions) in total. We obtain its electronic structure and absorption spectrum in less than a day of computation time
Niclasens von Weyl XI. Translation: Process des Hieronymus auf dem Concil zu Costnitz : mit Poggius lateinischem Urtexte sowie mit sprachlichen und litterarhistorischen Anmerkungen
vom Oberlehrer Niemeye
Accelerating Analytic-Continuation GW Calculations with a Laplace Transform and Natural Auxiliary Functions
We
present a simple and accurate GW implementation based
on a combination
of a Laplace transform (LT) and other acceleration techniques used
in post-self-consistent field quantum chemistry, namely, natural auxiliary
functions and the frozen-core approximation. The LT-GW approach combines
three major benefits: (a) a small prefactor for computational scaling,
(b) easy integration into existing molecular GW implementations, and
(c) significant performance improvements for a wide range of possible
applications. Illustrating these advantages for systems consisting
of up to 352 atoms and 7412 basis functions, we further demonstrate
the benefits of this approach combined with an efficient implementation
of the Bethe–Salpeter equation
Inter-subsystem charge-transfer excitations in exact subsystem time-dependent density-functional theory
Light-Enabled Deracemization of Cyclopropanes by Al-Salen Photocatalysis
Privileged chiral catalysts continue to transform the reactivity landscape, but achieving parity in excited state paradigms remains a frontier in contemporary synthesis. Whilst the interception of photogenerated intermediates by ground state cycles has partially addressed this challenge, single, chiral photocatalysts that simultaneously regulate reactivity and selectivity remain conspicuously scarce. Existing strategies leverage precision donor-acceptor recognition motifs to orchestrate enantioinduction. Expanding the latitude of this emerging branch of photocatalysis to incorporate simple, ubiquitous recognition units would be highly enabling but requires a suite of privileged photocatalysts. Motivated by the well-defined photo-physical properties of chiral Al-salen complexes, the efficiency of this privileged catalyst has been investigated and validated in the highly enantioselective deracemization of cyclopropyl ketones (up to 98:2 e.r.)
qcserenity/serenity: Release 1.5.3
<h2>Release 1.5.3 (25.10.2023)</h2>
<h3>Functionalities</h3>
<ul>
<li>Added two flavors of restricted open-shell HF and KS for the ground-state (Niklas Niemeyer)</li>
<li>Fermi-shifted Huzinaga EO Kernel for subsystem TDDFT (Niklas Niemeyer)</li>
<li>Laplace-Transform GW (Johannes Tölle, Niklas Niemeyer)</li>
<li>Renamed ReadOrbitalsTask to OrbitalsIOTask (Niklas Göllmann)</li>
<li>Added the functionality to write Turbomole files (Niklas Göllmann)</li>
<li>Added the functionality to write Molden files for both spherical and cartesian harmonics (Niklas Göllmann)</li>
<li>Added three schemes to generate complete basis function products for the Cholesky
decomposition framework: Simple, First, Complete (Lars Hellmann)</li>
<li>Added the functionality to control density fitting for individual
contributions (Coulomb, exchange, long-range exchange, correlation)</li>
</ul>