The heat of formation of the norbornyl cation

1970 ◽  
Vol 48 (2) ◽  
pp. 384-385 ◽  
Author(s):  
H. Spencer ◽  
Y. K. Mo
Keyword(s):  
Experimental Data ◽  
Heat Of Formation ◽  
Heats Of Formation ◽  
Quantum Mechanical ◽  
Mechanical Methods

The heat of formation of the norbornyl ion has been evaluated from experimental data. This was compared to the heats of formation of various formulations of the norbornyl ion computed by quantum mechanical methods.

scholarly journals On the Heats of Formation of Alkanes

2019 ◽  
Vol 53 (3) ◽  
Author(s):  
Jenn-Huei Lii ◽  
Norman L. Allinger
Keyword(s):  
Computational Methods ◽  
Heats Of Formation ◽  
Quantum Mechanical ◽  
Experimental Accuracy ◽  
Dispersion Energy ◽  
Test Set ◽  
Mechanical Methods

A broad diverse test set of alkanes and cycloalkanes previously studied with MM4 calculations has had the heats of formation calculated by several different quantum mechanical methods: HartreeFock, MP2, and MP4, and also by B3LYP and B3LYP + dispersion energy. Overall, three computational methods (MM4, MP4, and B3LYP + dispersion) yield results that are generally of experimental accuracy. These results are analyzed and compared in some detail.

scholarly journals Interactions between large molecules pose a puzzle for reference quantum mechanical methods

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yasmine S. Al-Hamdani ◽  
Péter R. Nagy ◽  
Andrea Zen ◽  
Dennis Barton ◽  
Mihály Kállay ◽  
...  
Keyword(s):  
Experimental Information ◽  
Quantum Mechanical ◽  
Interaction Energies ◽  
Small Organic Molecules ◽  
Large Molecules ◽  
Reference Information ◽  
Mechanical Methods ◽  
Non Covalent Interactions ◽  
Semi Empirical ◽  
Covalent Interactions

AbstractQuantum-mechanical methods are used for understanding molecular interactions throughout the natural sciences. Quantum diffusion Monte Carlo (DMC) and coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] are state-of-the-art trusted wavefunction methods that have been shown to yield accurate interaction energies for small organic molecules. These methods provide valuable reference information for widely-used semi-empirical and machine learning potentials, especially where experimental information is scarce. However, agreement for systems beyond small molecules is a crucial remaining milestone for cementing the benchmark accuracy of these methods. We show that CCSD(T) and DMC interaction energies are not consistent for a set of polarizable supramolecules. Whilst there is agreement for some of the complexes, in a few key systems disagreements of up to 8 kcal mol−1 remain. These findings thus indicate that more caution is required when aiming at reproducible non-covalent interactions between extended molecules.

scholarly journals A Review on Combination of Ab Initio Molecular Dynamics and NMR Parameters Calculations

2021 ◽  
Vol 22 (9) ◽  
pp. 4378
Author(s):  
Anna Helena Mazurek ◽  
Łukasz Szeleszczuk ◽  
Dariusz Maciej Pisklak
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Small Amplitude ◽  
Ab Initio Molecular Dynamics ◽  
Quantum Mechanical ◽  
Time Step ◽  
Noticeable Effect ◽  
Nmr Parameters ◽  
Mechanical Methods ◽  
Simulation Time

This review focuses on a combination of ab initio molecular dynamics (aiMD) and NMR parameters calculations using quantum mechanical methods. The advantages of such an approach in comparison to the commonly applied computations for the structures optimized at 0 K are presented. This article was designed as a convenient overview of the applied parameters such as the aiMD type, DFT functional, time step, or total simulation time, as well as examples of previously studied systems. From the analysis of the published works describing the applications of such combinations, it was concluded that including fast, small-amplitude motions through aiMD has a noticeable effect on the accuracy of NMR parameters calculations.

scholarly journals New Approach for Correcting Noncovalent Interactions in Semiempirical Quantum Mechanical Methods: The Importance of Multiple-Orientation Sampling

2021 ◽  
Vol 17 (9) ◽  
pp. 5556-5567
Author(s):  
Sergio Pérez-Tabero ◽  
Berta Fernández ◽  
Enrique M. Cabaleiro-Lago ◽  
Emilio Martínez-Núñez ◽  
Saulo A. Vázquez
Keyword(s):  
Noncovalent Interactions ◽  
Quantum Mechanical ◽  
New Approach ◽  
Mechanical Methods

Quantum Mechanical Methods for the Investigation of Metalloproteins and Related Bioinorganic Compounds

2014 ◽  
pp. 207-268 ◽  
Author(s):  
Luca Bertini ◽  
Maurizio Bruschi ◽  
Ugo Cosentino ◽  
Claudio Greco ◽  
Giorgio Moro ◽  
...  
Keyword(s):  
Quantum Mechanical ◽  
Mechanical Methods

scholarly journals Studying the excited electronic states of guanine rich DNA quadruplexes by quantum mechanical methods: main achievements and perspectives

2020 ◽  
Vol 19 (4) ◽  
pp. 436-444 ◽  
Author(s):  
Lara Martínez-Fernández ◽  
Luciana Esposito ◽  
Roberto Improta
Keyword(s):  
Electronic States ◽  
Quantum Mechanical ◽  
Excited Electronic States ◽  
Mechanical Methods ◽  
Dna Quadruplexes

Calculations are providing more and more useful insights into the interaction between light and DNA quadruplexes.

Sign in / Sign up

Export Citation Format

Share Document