Quantum Chemical B3LYP/cc-pvqz Computation of Ground-State Structures and Properties of Small Molecules with Atoms of Z ≤ 18 (Hydrogen to Argon) (IUPAC Technical Report)

2002 ◽  
Vol 24 (2) ◽  
Keyword(s):  
Small Molecules ◽  
Ground State ◽  
Quantum Chemical ◽  
Structures And Properties ◽  
Technical Report ◽  
Ground State Structures

Quantum chemical B3LYP/cc-pvqz computation of ground-state structures and properties of small molecules with atoms of Z ≤ 18 (hydrogen to argon)(IUPAC Technical Report)

2001 ◽  
Vol 73 (9) ◽  
pp. 1521-1553 ◽  
Author(s):  
Rudolf Janoschek
Keyword(s):  
Small Molecules ◽  
Ground State ◽  
Quantum Chemical ◽  
Density Functional ◽  
Spectroscopic Properties ◽  
Computational Method ◽  
Coupling Constants ◽  
Basis Sets ◽  
General Question ◽  
Absolute Deviation

Since density functional theory (DFT) achieved a remarkable break-through in computational chemistry, the important general question "How reliable are quantum chemical calculations for spectroscopic properties?" should be answered anew. In this project, the most successful density functionals, namely the Becke B3LYP functionals, and the correlation-consistent polarized valence quadruple zeta basis sets (cc-pvqz) are applied to small molecules. In particular, the complete set of experimentally known diatomic molecules formed by the atoms H to Ar (these are 214 species) is uniformly calculated, and calculated spectroscopic properties are compared with experimental ones. Computationally demanding molecules, such as open-shell systems, anions, or noble gas compounds, are included in this study. Investigated spectroscopic properties are spectroscopic ground state, equilibrium internuclear distance, harmonic vibrational wavenumber, anharmonicity, vibrational absolute absorption intensity, electric dipole moment, ionization potential, and dissociation energy. The same computational method has also been applied to the ground-state geometries of 56 polyatomic molecules up to the size of benzene. Special sections are dedicated to nuclear magnetic resonance (NMR) chemical shifts and isotropic hyperfine coupling constants. Each set of systems for a chosen property is statistically analyzed, and the above important question "How reliable...?" is mathematically answered by the mean absolute deviation between calculated and experimental data, as well as by the worst agreement. In addition to presentation of numerous quantum chemically calculated spectroscopic properties, a corresponding updated list of references for experimentally determined properties is presented.

Unexpected ground-state structures and properties of carbon nitride C3N at ambient and high pressures

2018 ◽  
Vol 140 ◽  
pp. 45-53 ◽  
Author(s):  
Qinghua Wu ◽  
Qianku Hu ◽  
Yiming Hou ◽  
Haiyan Wang ◽  
Aiguo Zhou ◽  
...  
Keyword(s):  
Ground State ◽  
Carbon Nitride ◽  
High Pressures ◽  
Structures And Properties ◽  
Ground State Structures

scholarly journals Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

2013 ◽  
Vol 88 (18) ◽  
Author(s):  
Guoying Gao ◽  
Roald Hoffmann ◽  
N. W. Ashcroft ◽  
Hanyu Liu ◽  
Aitor Bergara ◽  
...  
Keyword(s):  
Ground State ◽  
Theoretical Study ◽  
Structures And Properties ◽  
Ground State Structures

Computationally Augmented Retrosynthesis: Total Synthesis of Paspaline A and Emindole PB

2018 ◽  
Author(s):  
Timothy Newhouse ◽  
Daria E. Kim ◽  
Joshua E. Zweig
Keyword(s):  
Chemical Synthesis ◽  
Total Synthesis ◽  
Small Molecules ◽  
First Principles ◽  
Quantum Chemical ◽  
Computational Analysis ◽  
Empirical Evaluation ◽  
Synthetic Strategy ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions

The diverse molecular architectures of terpene natural products are assembled by exquisite enzyme-catalyzed reactions. Successful recapitulation of these transformations using chemical synthesis is hard to predict from first principles and therefore challenging to execute. A means of evaluating the feasibility of such chemical reactions would greatly enable the development of concise syntheses of complex small molecules. Herein, we report the computational analysis of the energetic favorability of a key bio-inspired transformation, which we use to inform our synthetic strategy. This approach was applied to synthesize two constituents of the historically challenging indole diterpenoid class, resulting in a concise route to (–)-paspaline A in 9 steps from commercially available materials and the first pathway to and structural confirmation of emindole PB in 13 steps. This work highlights how traditional retrosynthetic design can be augmented with quantum chemical calculations to reveal energetically feasible synthetic disconnections, minimizing time-consuming and expensive empirical evaluation.

scholarly journals How metallylenes activate small molecules

2021 ◽  
Vol 12 (12) ◽  
pp. 4526-4535
Author(s):  
Pascal Vermeeren ◽  
Michael T. Doppert ◽  
F. Matthias Bickelhaupt ◽  
Trevor A. Hamlin
Keyword(s):  
Small Molecules ◽  
Quantum Chemical ◽  
Rational Design ◽  
Chemical Analyses

Quantum chemical analyses reveal how model metallylene catalysts activate H2. This is the first step towards the rational design of metallylenes for the activation of small molecules and subsequent reactions.

STRUCTURE, STABILITY, AND ELECTRONIC PROPERTIES OF LARGE FULLERENES

1993 ◽  
Vol 07 (26) ◽  
pp. 4305-4329 ◽  
Author(s):  
C.Z. WANG ◽  
B.L. ZHANG ◽  
K.M. HO ◽  
X.Q. WANG
Keyword(s):  
Total Energy ◽  
Electronic Properties ◽  
Ground State ◽  
Relative Stability ◽  
Chemical Reactivity ◽  
Structure Stability ◽  
Quantum Mechanical ◽  
Efficient Scheme ◽  
Ground State Structures ◽  
Fullerene Clusters

The recent development in understanding the structures, relative stability, and electronic properties of large fullerenes is reviewed. We describe an efficient scheme to generate the ground-state networks for fullerene clusters. Combining this scheme with quantum-mechanical total-energy calculations, the ground-state structures of fullerenes ranging from C 20 to C 100 have been studied. Fullerenes of sizes 60, 70, and 84 are found to be energetically more stable than their neighbors. In addition to the energies, the fragmentation stability and the chemical reactivity of the clusters are shown to be important in determining the abundance of fullerene isomers.

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