A real-time method to reduce ballistocardiogram artifacts from EEG during fMRI based on optimal basis sets (OBS)

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

scholarly journals Role of Exchange and Correlation in High-Harmonic Generation Spectra of H2, N2 and CO2: Real-Time Time-Dependent Electronic-Structure Approaches

2020 ◽  
Author(s):  
Emanuele Coccia ◽  
Eleonora Luppi ◽  
Carlo Federico Pauletti
Keyword(s):  
Real Time ◽  
Harmonic Generation ◽  
Density Functional ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Time Dependent ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Exchange And Correlation

<p>This study arises from the attempt to answer the following question: how different descriptions of electronic exchange and correlation affect the high-harmonic generation (HHG) spectroscopy of H2, N2 and CO2 molecules? We compare HHG spectra for H2, N2 and CO2 with different ab initio electronic structures methods: real-time time-dependent configuration interaction (RT-TDCIS) and real-time time-dependent density functional theory (RT-TDDFT) using truncated basis sets composed of correlated wave functions expanded on Gaussian basis sets. In the framework of RT-TDDFT, we employ PBE and LC-ωPBE functionals. We study HHG spectroscopy by disentangling the effect of electronic exchange and correlation. We first analyse the electronic exchange alone and in the case of RT-TDDFT with LC-ωPBE, we use ω = 0.3 and ω = 0.4 to tune the percentage of long-range Hartree-Fock exchange and of short-range exchange PBE. Then, we added the correlation as described by PBE functional. All the methods give very similar HHG spectra and they seem not to be particularly sensitive to the different description of exchange and correlation or to the correct asymptotic behaviour of the Coulomb potential. Despite this general trend, some differences are found in the region connecting the cutoff and the background. Here, the harmonics can be resolved with different accuracy depending on the theoretical schemes used. We believe that the investigation of the molecular continuum and its coupling with strong fields merits further theoretical investigations in the next future. </p>

Optimal basis sets for CBS extrapolation of the correlation energy: oVxZ and oV(x+d)Z

2019 ◽  
Vol 150 (15) ◽  
pp. 154106 ◽  
Author(s):  
A. J. C. Varandas ◽  
F. N. N. Pansini
Keyword(s):  
Correlation Energy ◽  
Basis Sets ◽  
Optimal Basis

Optimal basis sets for detailed Brillouin-zone integrations

1996 ◽  
Vol 54 (23) ◽  
pp. 16464-16469 ◽  
Author(s):  
Eric L. Shirley
Keyword(s):  
Brillouin Zone ◽  
Basis Sets ◽  
Optimal Basis

Optimal basis for real-time compression of ultrasound RF signals

2013 ◽  
Author(s):  
Sharmin Kibria ◽  
Patrick Kelly ◽  
Tamara Sobers ◽  
Jai Gupta ◽  
Linda Gupta
Keyword(s):  
Real Time ◽  
Optimal Basis ◽  
Time Compression ◽  
Rf Signals

Construction of Optimal Basis Sets in Approximate Theories of the Electronic Structure of Molecules

1981 ◽  
Vol 36 (4) ◽  
pp. 373-377
Author(s):  
Z. B. Maksić
Keyword(s):  
Electronic Structure ◽  
Basis Functions ◽  
Basis Sets ◽  
Optimal Basis ◽  
Structure Of Molecules ◽  
Löwdin Orthogonalization ◽  
Orthogonalization Procedure

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

scholarly journals Role of Exchange and Correlation in High-Harmonic Generation Spectra of H2, N2 and CO2: Real-Time Time-Dependent Electronic-Structure Approaches

2020 ◽  
Author(s):  
Emanuele Coccia ◽  
Eleonora Luppi ◽  
Carlo Federico Pauletti
Keyword(s):  
Real Time ◽  
Harmonic Generation ◽  
Density Functional ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Time Dependent ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Exchange And Correlation

<p>This study arises from the attempt to answer the following question: how different descriptions of electronic exchange and correlation affect the high-harmonic generation (HHG) spectroscopy of H2, N2 and CO2 molecules? We compare HHG spectra for H2, N2 and CO2 with different ab initio electronic structures methods: real-time time-dependent configuration interaction (RT-TDCIS) and real-time time-dependent density functional theory (RT-TDDFT) using truncated basis sets composed of correlated wave functions expanded on Gaussian basis sets. In the framework of RT-TDDFT, we employ PBE and LC-ωPBE functionals. We study HHG spectroscopy by disentangling the effect of electronic exchange and correlation. We first analyse the electronic exchange alone and in the case of RT-TDDFT with LC-ωPBE, we use ω = 0.3 and ω = 0.4 to tune the percentage of long-range Hartree-Fock exchange and of short-range exchange PBE. Then, we added the correlation as described by PBE functional. All the methods give very similar HHG spectra and they seem not to be particularly sensitive to the different description of exchange and correlation or to the correct asymptotic behaviour of the Coulomb potential. Despite this general trend, some differences are found in the region connecting the cutoff and the background. Here, the harmonics can be resolved with different accuracy depending on the theoretical schemes used. We believe that the investigation of the molecular continuum and its coupling with strong fields merits further theoretical investigations in the next future. </p>

scholarly journals Basis Set Selection for Calculation of Structural and Electronic Properties of Systems Incorporating a Superoxide Radical in an Aqueous Medium

2021 ◽  
pp. 53-57
Author(s):  
A.V. Ryabykh ◽  
M.A. Pirogov ◽  
O.A. Maslova ◽  
S.A. Beznosyuk
Keyword(s):  
Aqueous Medium ◽  
Superoxide Radical ◽  
Selection Criterion ◽  
Polarizable Continuum Model ◽  
Basis Set ◽  
Basis Sets ◽  
Optimal Basis ◽  
Molecular Systems ◽  
Structural And Electronic Properties ◽  
Computer Calculations

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.

Removal of FMRI environment artifacts from EEG data using optimal basis sets

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):  
Basis Sets ◽  
Optimal Basis ◽  
Eeg Data
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