Decomposition pathways of formamide in the presence of vanadium and titanium monoxides

2015 ◽  
Vol 17 (26) ◽  
pp. 16927-16936 ◽  
Author(s):  
Huyen Thi Nguyen ◽  
Minh Tho Nguyen

Thermally feasible decomposition pathways of formamide (FM) in the presence of vanadium VO(X4Σ−) and titanium TiO(X3Δ) monoxides are determined using density functional theory (the BP86 functional) and coupled-cluster theory (CCSD(T)) computations with large basis sets.

2020 ◽  
Vol 246 ◽  
pp. 00006
Author(s):  
Anneke Dittmer

The following article gives a brief introduction to quantum chemistry and its application to the prediction of band gaps of inorganic and organic semiconductors. Two important quantum chemistry concepts —Density Functional Theory (DFT) and Coupled Cluster Theory (CC)— are shortly explained. These two concepts are used to calculate the optical and the transport band gap of a set of semiconductors modelled with an electrostatic embedding approach.


2015 ◽  
Vol 17 (27) ◽  
pp. 17854-17863 ◽  
Author(s):  
Pierre Guiglion ◽  
Martijn A. Zwijnenburg

We use a combination of Time-Dependent Density Functional Theory (TD-DFT) and approximate Coupled Cluster Theory (RI-CC2) to compare trends in the optical gap and fluorescence energies of ortho-, meta- and para-oligomers of phenylene.


2019 ◽  
Author(s):  
Kamal Batra ◽  
Stefan Zahn ◽  
Thomas Heine

<p>We thoroughly benchmark time-dependent density- functional theory for the predictive calculation of UV/Vis spectra of porphyrin derivatives. With the aim to provide an approach that is computationally feasible for large-scale applications such as biological systems or molecular framework materials, albeit performing with high accuracy for the Q-bands, we compare the results given by various computational protocols, including basis sets, density-functionals (including gradient corrected local functionals, hybrids, double hybrids and range-separated functionals), and various variants of time-dependent density-functional theory, including the simplified Tamm-Dancoff approximation. An excellent choice for these calculations is the range-separated functional CAM-B3LYP in combination with the simplified Tamm-Dancoff approximation and a basis set of double-ζ quality def2-SVP (mean absolute error [MAE] of ~0.05 eV). This is not surpassed by more expensive approaches, not even by double hybrid functionals, and solely systematic excitation energy scaling slightly improves the results (MAE ~0.04 eV). </p>


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