Optimal basis sets for detailed Brillouin-zone integrations

1996 ◽  
Vol 54 (23) ◽  
pp. 16464-16469 ◽  
Author(s):  
Eric L. Shirley
2019 ◽  
Vol 150 (15) ◽  
pp. 154106 ◽  
Author(s):  
A. J. C. Varandas ◽  
F. N. N. Pansini

1981 ◽  
Vol 36 (4) ◽  
pp. 373-377
Author(s):  
Z. B. Maksić

Properties of the weighted Löwdin orthogonalization procedure are thoroughly discussed. It is shown that its flexibility might be very useful in the construction of optimal truncated basis sets in approximate theories of the electronic structure of molecules and solids. The relevance of pairwise nonorthogonal (hybrid) basis functions is pointed out


2016 ◽  
Vol 127 ◽  
pp. 114-125 ◽  
Author(s):  
Xia Wu ◽  
Tong Wu ◽  
Zhichao Zhan ◽  
Li Yao ◽  
Xiaotong Wen
Keyword(s):  

Author(s):  
A.V. Ryabykh ◽  
M.A. Pirogov ◽  
O.A. Maslova ◽  
S.A. Beznosyuk

In this work, computer simulation has been carried out, and the molecular parameters of oxygen and a superoxide ion have been calculated to select the most optimal basis set of functions for further quantum mechanical calculations that include the presence of reactive oxygen species. For each particle, the equilibrium bond lengths and averaged polarizabilities in a continuous dielectric aqueous medium are obtained with the Conductor-like Polarizable Continuum Model (CPCM) and Solvation Model based on Density (SMD). Calculations for the 16 basic sets are conducted using the Orca software package. The obtained numerical values are compared with experimental data. The electron affinity energy of the oxygen molecule is used as the main selection criterion. The total time of computer calculations for each basis set is considered, and the most optimal basis sets are selected. The basis sets 6-31+G(d), 6-311+G, def2-TZVPD, and aug-cc-pVDZ are recommended for numerical calculations of molecular systems incorporating molecular oxygen and superoxide radical as its reduction product.


NeuroImage ◽  
2005 ◽  
Vol 28 (3) ◽  
pp. 720-737 ◽  
Author(s):  
R.K. Niazy ◽  
C.F. Beckmann ◽  
G.D. Iannetti ◽  
J.M. Brady ◽  
S.M. Smith
Keyword(s):  

2015 ◽  
Vol 8 (2) ◽  
pp. 2122-2134
Author(s):  
Sarvendra Kumar ◽  
Rajesh Kumar ◽  
Jayant Teotia ◽  
M. K. Yadav

In the present work, UV- Visible spectra of 2-Chloro-3,4-Dimethoxybenzaldehyde (2,3,4-CDMB) compound  have been carried out experimentally and theoretically. The ultraviolet absorption spectrum of title compound in three solvents (Acetone, Diethyl Ether, CCl4) of different polarity were examined in the range of 200–500 nm. The structure of the molecule was optimized and the structural characteristics were determined by HF and DFT (B3LYP) methods with 6-31+G(d,p) and 6-311++G(d,p) as basis sets. The excitation energy, wavelength corresponds to absorption maxima () and oscillator strength (f) are calculated by Time-Dependent Density Functional Theory (TD-DFT) using B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) as basis sets. The electric dipole moment (μ), polarizability (α) and the first hyperpolarizability (β ) have been computed to evaluate the non-linear optical (NLO) response of the investigated compound by HF and DFT (B3LYP) with already mentioned basis sets. Thermodynamic functions of the title compound at different temperatures were also calculated.


2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).


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