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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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Characterization of the Short-Range Couplings in Excitation Energy Transfer

TL;DR: Voityuk et al. as mentioned in this paper developed a new scheme to account for the EET coupling by generalizing the fragment charge difference scheme, and the short-range coupling is defined as the contribution from Dexter's exchange coupling and the overlap effect, which is very similar to the triplet−triplet energy transfer coupling in both magnitudes and the distance dependences.
Journal ArticleDOI

Time-Dependent Density-Functional Description of the (1)La State in Polycyclic Aromatic Hydrocarbons: Charge-Transfer Character in Disguise?

TL;DR: It is concluded that TD-DFT calculations in medium-size, conjugated organic molecules may involve significant but hard-to-detect errors, and the (1)La states of certain PAHs exhibit some sort of charge-separated character, consistent with the description of this state within valence-bond theory, but such character proves difficult to identify a priori.
Journal ArticleDOI

A Model of Plasma-Biofilm and Plasma-Tissue Interactions at Ambient Pressure

TL;DR: In this paper, the authors present a model framework for plasma-biofilm and plasma-tissue interactions that can link molecular simulation of plasma chemistry to functions at a cell population level or a tissue level.
Journal ArticleDOI

Fast and highly chemoselective alkynylation of thiols with hypervalent iodine reagents enabled through a low energy barrier concerted mechanism.

TL;DR: The mechanism and full scope of the alkynylation of thiols using ethynyl benziodoxolone (EBX) hypervalent iodine reagents is described and a new, three-atom concerted transition state with a very low energy barrier is discovered, which rationalizes the high reaction rate.
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Pronounced sponge-like nanostructure in propylammonium nitrate

TL;DR: The bulk structure of the ionic liquid propylammonium nitrate has been determined using neutron diffraction and empirical potential structure refinement fits to the data show that PAN self-assembles into a quasi-periodic bicontinuous nanostructure reminiscent of an amphiphile L(3)-sponge phase.
References
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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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TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
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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