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Advances in methods and algorithms in a modern quantum chemistry program package

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TLDR
Specific developments discussed include fast methods for density functional theory calculations, linear scaling evaluation of energies, NMR chemical shifts and electric properties, fast auxiliary basis function methods for correlated energies and gradients, equation-of-motion coupled cluster methods for ground and excited states, geminal wavefunctions, embedding methods and techniques for exploring potential energy surfaces.
Abstract
Advances in theory and algorithms for electronic structure calculations must be incorporated into program packages to enable them to become routinely used by the broader chemical community. This work reviews advances made over the past five years or so that constitute the major improvements contained in a new release of the Q-Chem quantum chemistry package, together with illustrative timings and applications. Specific developments discussed include fast methods for density functional theory calculations, linear scaling evaluation of energies, NMR chemical shifts and electric properties, fast auxiliary basis function methods for correlated energies and gradients, equation-of-motion coupled cluster methods for ground and excited states, geminal wavefunctions, embedding methods and techniques for exploring potential energy surfaces.

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Exploring the influence of organic species on pre- and post-nucleation calcium carbonate

TL;DR: In this paper, a combination of experimental and theoretical methods has been used to probe how three simple additives, containing varying numbers of carboxylate groups, influence the early stages of the growth of calcium carbonate.
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Distance-dependent Schwarz-based integral estimates for two-electron integrals: Reliable tightness vs. rigorous upper bounds

TL;DR: The efficiency of the QQR estimates within SCF theory is studied and the performance for a benchmark set of 44 medium to large molecules is demonstrated, showing that reliable tightness of integral estimates is more important for the screening performance than rigorous upper bound properties.
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Theoretical Characterization of the Air-Stable, High-Mobility Dinaphtho[2,3-b:2′3′-f]thieno[3,2-b]-thiophene Organic Semiconductor

TL;DR: In this paper, the authors investigated the microscopic charge transport parameters of the DNTT molecule and crystal and showed that the moderate anisotropy of the hole mobility is highly dependent on the presence of in-plane herring-bonelike intermolecular interactions with large electronic coupling (transfer integral) values (ca. 0.1 eV).
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Investigating the Dearomative Rearrangement of Biaryl Phosphine-Ligated Pd(II) Complexes

TL;DR: A series of monoligated L·PdII(Ar)X complexes (L = dialkyl biaryl phosphine) have been prepared and studied in an effort to better understand an unusual dearomative rearrangement previously documented in these systems.
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Structure of the aqueous electron: assessment of one-electron pseudopotential models in comparison to experimental data and time-dependent density functional theory.

TL;DR: This work examines a new electron-water pseudopotential model that predicts a more delocalized wave function and no well-defined solvent cavity and finds that the cavity-forming models are far more consistent with the experimental data for the electron's radius of gyration, optical absorption spectrum, and vertical electron binding energy.
References
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Journal ArticleDOI

Density‐functional thermochemistry. III. The role of exact exchange

TL;DR: In this article, a semi-empirical exchange correlation functional with local spin density, gradient, and exact exchange terms was proposed. But this functional performed significantly better than previous functionals with gradient corrections only, and fits experimental atomization energies with an impressively small average absolute deviation of 2.4 kcal/mol.
Journal ArticleDOI

Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen

TL;DR: In this paper, a detailed study of correlation effects in the oxygen atom was conducted, and it was shown that primitive basis sets of primitive Gaussian functions effectively and efficiently describe correlation effects.

疟原虫var基因转换速率变化导致抗原变异[英]/Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

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Journal ArticleDOI

General atomic and molecular electronic structure system

TL;DR: A description of the ab initio quantum chemistry package GAMESS, which can be treated with wave functions ranging from the simplest closed‐shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication.
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