Study on the maximum accuracy of the pseudopotential density functional method with localized atomic orbitals versus plane-wave basis sets

2008 ◽  
Vol 128 (4) ◽  
pp. 044102 ◽  
Author(s):  
Michele Gusso
Keyword(s):  
Plane Wave ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Sets ◽  
Atomic Orbitals ◽  
Maximum Accuracy ◽  
Versus Plane

scholarly journals Origin Invariant Full Optical Rotation Tensor in the Length Dipole Gauge without London Atomic Orbitals

2021 ◽  
Author(s):  
Marco Caricato
Keyword(s):  
Electron Correlation ◽  
Density Functional ◽  
Optical Rotation ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Set ◽  
Rotation Tensor ◽  
Atomic Orbitals ◽  
Complete Basis Set ◽  
Approximate Wave

<div> <div> <div> <p>We present an origin-invariant approach to compute the full optical rotation tensor (Buckingham/Dunn tensor) in the length dipole gauge without recourse to London atomic orbitals, called LG(OI). The LG(OI) approach is simpler and less computationally demanding than the more common LG-London and modified velocity gauge (MVG) approaches and it can be used with any approximate wave function or density functional method. We report an implementation at coupled cluster with single and double excitations level (CCSD), for which we present the first simulations of the origin-invariant Buckingham/Dunn tensor in the length gauge. With this method, we attempt to decouple the effects of electron correlation and basis set incompleteness on the choice of gauge for optical rotation calculations on simple test systems. The simulations show a smooth convergence of the LG(OI) and MVG results with the basis set size towards the complete basis set limit. However, these preliminary results indicate that CCSD may not be close to a complete description of the electron correlation effects on this property even for small molecules, and that basis set incompleteness may be a less important cause of discrepancy between choices of gauge than electron correlation incompleteness. </p> </div> </div> </div>

scholarly journals Origin Invariant Optical Rotation in the Length Dipole Gauge without London Atomic Orbitals

2020 ◽  
Author(s):  
Marco Caricato
Keyword(s):  
Density Functional ◽  
Optical Rotation ◽  
Center Of Mass ◽  
Density Functional Method ◽  
Functional Method ◽  
Coupled Cluster ◽  
Atomic Orbitals ◽  
Numerical Tests ◽  
Approximate Wave Function ◽  
Approximate Wave

<div> <div> <div> <p>We present an approach to perform origin-invariant optical rotation calculations in the length dipole gauge without recourse to London atomic orbitals, called LG(OI). The LG(OI) approach works with any approximate wave function or density functional method, but here we focus on the implementation with the coupled cluster (CC) with single and double excitations method because of the lack of production-level alternatives. Preliminary numerical tests show the efficacy of the LG(OI) procedure, and indicate that conventional CC-LG calculations with the origin in the center of mass of a molecule may still carry significant origin dependence. </p> </div> </div> </div>

Density-functional method for very large systems with LCAO basis sets

1997 ◽  
Vol 65 (5) ◽  
pp. 453-461 ◽  
Author(s):  
Daniel S�nchez-Portal ◽  
Pablo Ordej�n ◽  
Emilio Artacho ◽  
Jos� M. Soler
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Sets ◽  
Large Systems

scholarly journals Origin Invariant Optical Rotation in the Length Dipole Gauge without London Atomic Orbitals

2020 ◽  
Author(s):  
Marco Caricato
Keyword(s):  
Density Functional ◽  
Optical Rotation ◽  
Center Of Mass ◽  
Density Functional Method ◽  
Functional Method ◽  
Coupled Cluster ◽  
Atomic Orbitals ◽  
Numerical Tests ◽  
Approximate Wave Function ◽  
Approximate Wave

<div> <div> <div> <p>We present an approach to perform origin-invariant optical rotation calculations in the length dipole gauge without recourse to London atomic orbitals, called LG(OI). The LG(OI) approach works with any approximate wave function or density functional method, but here we focus on the implementation with the coupled cluster (CC) with single and double excitations method because of the lack of production-level alternatives. Preliminary numerical tests show the efficacy of the LG(OI) procedure, and indicate that conventional CC-LG calculations with the origin in the center of mass of a molecule may still carry significant origin dependence. </p> </div> </div> </div>

scholarly journals Динамическая поляризуемость отрицательного иона водорода

2021 ◽  
Vol 129 (1) ◽  
pp. 22
Author(s):  
В.Е. Чернов ◽  
Б.А. Зон ◽  
А.С. Корнев
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
High Accuracy ◽  
Basis Sets ◽  
Neutral Atoms ◽  
Frequency Dependent ◽  
Large Size ◽  
Correlation Consistent ◽  
Consistent Basis

We performed the calculations of the frequency-dependent polarizability of a hydrogen anion by using correlation-consistent basis sets with high diffuseness. The results obtained turned out to be close to the results obtained by the method of summation over pseudo-states. It is also shown that calculations by the density functional method do not allow obtaining high accuracy. This is due to the large size of anions compared to both cations and neutral atoms (molecules).

scholarly journals Origin Invariant Full Optical Rotation Tensor in the Length Dipole Gauge without London Atomic Orbitals

2021 ◽  
Author(s):  
Marco Caricato
Keyword(s):  
Electron Correlation ◽  
Density Functional ◽  
Optical Rotation ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Set ◽  
Rotation Tensor ◽  
Atomic Orbitals ◽  
Complete Basis Set ◽  
Approximate Wave

<div> <div> <div> <p>We present an origin-invariant approach to compute the full optical rotation tensor (Buckingham/Dunn tensor) in the length dipole gauge without recourse to London atomic orbitals, called LG(OI). The LG(OI) approach is simpler and less computationally demanding than the more common LG-London and modified velocity gauge (MVG) approaches and it can be used with any approximate wave function or density functional method. We report an implementation at coupled cluster with single and double excitations level (CCSD), for which we present the first simulations of the origin-invariant Buckingham/Dunn tensor in the length gauge. With this method, we attempt to decouple the effects of electron correlation and basis set incompleteness on the choice of gauge for optical rotation calculations on simple test systems. The simulations show a smooth convergence of the LG(OI) and MVG results with the basis set size towards the complete basis set limit. However, these preliminary results indicate that CCSD may not be close to a complete description of the electron correlation effects on this property even for small molecules, and that basis set incompleteness may be a less important cause of discrepancy between choices of gauge than electron correlation incompleteness. </p> </div> </div> </div>

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