Pseudo-atomic orbitals as basis sets for the O(<i>N</i>) DFT code CONQUEST

Torralba, Antonio Sánchez; Todorović, Milica; Brázdová, Veronika; Choudhury, R; Miyazaki, Tsuyoshi; Gillan, M. J.; Bowler, David R.

doi:10.1088/0953-8984/20/29/294206

Cited by 48 publications

(72 citation statements)

References 26 publications

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“…Additional functions are often adopted to describe polarization (P), for example, triple- with polarization (TZP). A conventional support function consisting of multiple- PAOs 5 is written as…”

Section: Multisite Support Functions In Conquestmentioning

confidence: 99%

“…CONQUEST provides two types of basis functions to express the support functions: b-spline (blip) finite-element functions 4 akin to plane-waves; and pseudo atomic orbitals (PAOs) 5 . We focus on the use of PAOs in the present study.…”

Section: Introductionmentioning

confidence: 99%

“…When increasing the number of PAOs, we often prepare 'multiple- ' functions in which several radial functions are combined with a spherical harmonic function. There are two ways to construct support functions with multiple- PAOs 5 :…”

Section: Introductionmentioning

confidence: 99%

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Efficient Calculations with Multisite Local Orbitals in a Large-Scale DFT Code CONQUEST

Nakata

Bowler

Miyazaki

2014

J. Chem. Theory Comput.

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Multisite local orbitals, which are formed from linear combinations of pseudo-atomic orbitals from a target atom and its neighbor atoms, have been introduced in the large-scale density functional theory calculation code CONQUEST. Multisite local orbitals correspond to local molecular orbitals so that the number of required local orbitals can be minimal. The multisite support functions are determined by using the localized filter diagonalization (LFD) method [Phys. Rev. B 2009, 80, 205104]. Two new methods, the double cutoff method and the smoothing method, are introduced to the LFD method to improve efficiency and stability. TheHamiltonian and overlap matrices with multisite local orbitals are constructed by efficient sparse-matrix multiplications in CONQUEST. The investigation of the calculated energetic and geometrical properties and band structures of bulk Si, Al and DNA systems demonstrate the accuracy and the computational efficiency of the present method. The representability of both occupied and unoccupied band structures with the present method has been also confirmed.3

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Section: Multisite Support Functions In Conquestmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Efficient Calculations with Multisite Local Orbitals in a Large-Scale DFT Code CONQUEST

Nakata

Bowler

Miyazaki

2014

J. Chem. Theory Comput.

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“…[13][14][15] When B-splines are used, we can systematically improve the accuracy of the basis set by reducing the grid spacing and can reach the planewave accuracy. On the other hand, we can employ efficient calculations with a reasonable accuracy by using PAOs as basis sets.…”

Section: Introductionmentioning

confidence: 99%

Linear-scaling first-principles molecular dynamics of complex biological systems with the Conquest code

Otsuka¹,

Taiji²,

Bowler

et al. 2016

Jpn. J. Appl. Phys.

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The recent progress of linear-scaling or OðNÞ methods in density functional theory (DFT) is remarkable. In this paper, we show that all-atom molecular dynamics simulations of complex biological systems based on DFT are now possible using our linear-scaling DFT code CONQUEST. We first overview the calculation methods used in CONQUEST and explain the method introduced recently to realise efficient and robust first-principles molecular dynamics (FPMD) with OðNÞ DFT. Then, we show that we can perform reliable all-atom FPMD simulations of a hydrated DNA model containing about 3400 atoms. We also report that the velocity scaling method is both reliable and useful for controlling the temperature of the FPMD simulation of this system. From these results, we conclude that reliable FPMD simulations of complex biological systems are now possible with CONQUEST.

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“…Similar to the PAOs, Ozaki and Kino 87,88 and others 89,90 used numerical solutions to the atomic Kohn-Sham equations as the secondary basis, and a scheme resembling geometry optimization to obtain the adaptive basis. The CONQUEST program 91 forms local "support functions" (an adaptive basis) from either functions akin to plane waves 92 or pseudoatomic orbitals 93 . The ONETEP package 94,95 forms non-orthogonal generalized Wannier functions (NGWFs) 96 as the environment-adapted basis, which a linear combination of periodic sinc functions confined in an atom-centered sphere of fixed radius.…”

Section: Kohn-sham Density Functional Theorymentioning

confidence: 99%

Approaching the basis set limit for DFT calculations using an environment-adapted minimal basis with perturbation theory: Formulation, proof of concept, and a pilot implementation

Mao

Horn

Mardirossian

et al. 2016

The Journal of Chemical Physics

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Recently developed density functionals have good accuracy for both thermochemistry (TC) and non-covalent interactions (NC) if very large basis sets are used. To approach the basis set limit with potentially lower costs, a new SCF scheme with minimal adaptive basis (MAB) functions variationally optimized on each atomic site is presented, and the desired accuracy can be obtained by applying a perturbative correction (PC). Compared to exact SCF results, using this MAB-SCF (PC) approach with the same target basis set produces < 0.15 kcal/mol RMS errors for most of the tested TC datasets, and < 0.1 kcal/mol for most of the NCs. The performance of density functionals near the basis set limit can be well reproduced with slight discrepancies. With further improvement to its implementation, MAB-SCF (PC) could be a promising substitute for its conventional counterpart to viably approach the basis set limit of modern density functionals.

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Pseudo-atomic orbitals as basis sets for the O(N) DFT code CONQUEST

Cited by 48 publications

References 26 publications

Efficient Calculations with Multisite Local Orbitals in a Large-Scale DFT Code CONQUEST

Efficient Calculations with Multisite Local Orbitals in a Large-Scale DFT Code CONQUEST

Linear-scaling first-principles molecular dynamics of complex biological systems with the Conquest code

Approaching the basis set limit for DFT calculations using an environment-adapted minimal basis with perturbation theory: Formulation, proof of concept, and a pilot implementation

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