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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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Journal ArticleDOI

A massively parallel tensor contraction framework for coupled-cluster computations

TL;DR: A distributed-memory numerical library (Cyclops Tensor Framework) that automatically manages tensor blocking and redistribution to perform any user-specified contractions and enables the expression of massively-parallel coupled-cluster methods via a concise tensor contraction interface.
Journal ArticleDOI

Scaled Second Order Perturbation Corrections to Configuration Interaction Singles: Efficient and Reliable Excitation Energy Methods

TL;DR: Two modifications of the perturbative doubles correction to configuration interaction with single substitutions (CIS(D)) are suggested, which are excited state analogues of ground state scaled second-order Møller-Plesset (MP2) methods, which significantly improve upon CIS(D) itself.
Journal ArticleDOI

A generalized many-body expansion and a unified view of fragment-based methods in electronic structure theory.

TL;DR: Preliminary applications to molecular and ionic clusters suggest that two-body methods in which dimers are constructed from intersecting fragments may be a route to achieve very high accuracy in fragment-based calculations.
Journal ArticleDOI

M2(m-dobdc) (M = Mg, Mn, Fe, Co, Ni) Metal–Organic Frameworks Exhibiting Increased Charge Density and Enhanced H2 Binding at the Open Metal Sites

TL;DR: A family of structural isomers of this framework, M2(m-dobdc) is reported, featuring exposed M(2+) cation sites with a higher apparent charge density, and the regioisomeric linker alters the symmetry of the ligand field at the metal sites, leading to increases of 0.4-1.5 kJ/mol in the H2 binding enthalpies relative to M2 (dobDC).
Journal ArticleDOI

Improved Prediction of Properties of π-Conjugated Oligomers with Range-Separated Hybrid Density Functionals

TL;DR: WB97XD is suitable for calculating band structures of conjugated polymers employing orbital energies and the accuracy of the negative orbital energies is good down to about 30 eV so that valence and innervalence PE spectra can be modeled.
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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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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