Activation Energies and Reaction Energetics for 1,3-Dipolar Cycloadditions of Hydrazoic Acid with CC and CN Multiple Bonds from High-Accuracy and Density Functional Quantum Mechanical Calculations

2005 ◽  
Vol 88 (7) ◽  
pp. 1702-1710 ◽  
Author(s):  
Gavin O. Jones ◽  
Daniel H. Ess ◽  
Kendall N. Houk
2019 ◽  
Author(s):  
Prachi Sharma ◽  
Dale Pahls ◽  
Bianca Ramirez ◽  
Connie C. Lu ◽  
Laura Gagliardi

We used density functional theory and multireference wave-function based methods to predict new heterobimetallic complexes featuring a uranium and a first-row transition metal. The quantum mechanical calculations predict a five-fold bonding between uranium and manganese metals.


2019 ◽  
Author(s):  
Prachi Sharma ◽  
Dale Pahls ◽  
Bianca Ramirez ◽  
Connie C. Lu ◽  
Laura Gagliardi

We used density functional theory and multireference wave-function based methods to predict new heterobimetallic complexes featuring a uranium and a first-row transition metal. The quantum mechanical calculations predict a five-fold bonding between uranium and manganese metals.


2020 ◽  
Author(s):  
Cheng-Wei Ju ◽  
Hanzhi Bai ◽  
Bo Li ◽  
Rizhang Liu

<div> <p>The development of functional organic fluorescent materials calls for fast and accurate predictions of photophysical parameters for processes such as high-throughput virtual screening, while the task is challenged by the limitations of quantum mechanical calculations. We establish a database covering >4,300 solvated organic fluorescent dyes and develop new machine learning (ML) approach aimed at efficient and accurate predictions of emission wavelength and photoluminescence quantum yield (PLQY). Our feature engineering has given rise to Functionalized Structure Descriptor (FSD) and Comprehensive General Solvent Descriptor (CGSD), whereby a highly black-box computational framework is realized with consistently good accuracy across different dye families, ability of describing substitution effects and solvent effects, efficiency for large-scale predictions and workability with on-the-fly learning. Evaluations with unseen molecules suggests a remarkable MAE of 0.13 for PLQY and 0.080 eV for emission energy, the latter comparable to time-dependent density functional theory (TD-DFT) calculations. An online prediction platform was constructed based on the ensemble model to make prediction in various solvents (https://www.chemfluor.top/). Our statistical learning methodology will complement quantum mechanical calculations as an efficient alternative approach for the prediction of these parameters.<br></p> </div><p> <br></p>


2015 ◽  
Vol 17 (9) ◽  
pp. 6423-6432 ◽  
Author(s):  
Mikuláš Kocman ◽  
Petr Jurečka ◽  
Matúš Dubecký ◽  
Michal Otyepka ◽  
Yeonchoo Cho ◽  
...  

Various dispersion-corrected density functionals are compared with high level QM data for several model complexes for adsorptive hydrogen storage.


Author(s):  
Björn Winkler ◽  
Victor Milman

AbstractQuantum mechanical calculations based on density functional theory and a generalized gradient approx imation have been used to study the pressure-induced B1 to B2 structural phase transition in YbN, YbP and YbAs. The phase transitions are predicted to occur at 137 GPa in YbN, at 25 GPa in YbP, and at 20 GPa in YbAs. These values are significantly lower than those predicted by empirical poten tial model calculations. Bulk moduli are predicted to be 136, 70 and 63 GPa for YbN, YbP and YbAs, respectively.


2021 ◽  
Vol 33 (9) ◽  
pp. 2105-2118
Author(s):  
Rehab Majed Kubba ◽  
Aisha Muthana Shanshal

The research includes unrestricted (UDFT) and (UPM3) quantum mechanical calculations for studying the reaction path of bonds rupture energies of (O-R) and (C-OAr) in twelve diclofenac derivatives containing different substituted organic groups. All the calculations were performed at the optimize geometries in vacuum phase by using Gaussian 09 program. Comparison was done between the studied diclofenac derivatives and the standard ionic diclofenac of sodium and potassium included geometrical structures, physical properties, total energies of the reactants and products, activation energies and transition states. The results showed that some substituted organic groups could be used to form good carrier bonds for the acidic drug diclofenac, while others were less efficient depending on the nature of the substituted carrier, and that there is a preference for carriers of the type (–R) over the carriers of the type (–Ar).


RSC Advances ◽  
2020 ◽  
Vol 10 (47) ◽  
pp. 28066-28074
Author(s):  
Chunrui Wang ◽  
Junfeng Shao ◽  
Fei Chen ◽  
Xiaowei Sheng

We perform accurate quantum mechanical calculations and analysis for the absorption of ZnPc in the first singlet excited state.


2005 ◽  
Vol 61 (2) ◽  
pp. 133-136 ◽  
Author(s):  
Luis Guillermo Cota ◽  
Pablo de la Mora

The two published lithium peroxide structures, both ascribed to the hexagonal P\bar 6 space group, were subjected to reinterpretation, and another more symmetric structure, now belonging to the P63/mmc space group, was found. Detailed density-functional quantum mechanical calculations and crystal structure optimizations were carried out on both structures and the energetic arguments obtained therewith helped to rule out one of them.


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