The quantum Monte Carlo method

Towler, M. D.

doi:10.1002/pssb.200642125

Cited by 23 publications

(19 citation statements)

References 87 publications

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“…9 Fixed-node diffusion Monte Carlo (FNDMC) is widely used in theoretical physics for highly accurate computational electronic structure theory calculations. 10 It has many very attractive features: it is a genuine many-body theory with an explicit description of electron correlation, it shows a favorable scaling of computational cost with system size (quadratic, at best), and involves a naturally parallel algorithm that can be made to scale almost linearly with the number of processors, allowing easy exploitation of grid resources as well as the new generation of 'petascale' machines. 11,12 Because of these advantages, FNDMC has drawn attention also from quantum chemistry.…”

Section: Methodological Aspectsmentioning

confidence: 99%

The Lithium–Thiophene Riddle Revisited

Korth¹,

Towler²

2011

J. Phys. Chem. A

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Abstract:A recent study of the interaction of a lithium atom with the thiophene molecule found a large disagreement between high-level coupled cluster (CCSD(T)/AVTZ) and quatum Monte Carlo (fixednode diffusion Monte Carlo, or FNDMC) calculations. We address this 'lithium-thiophene riddle' by analyzing the influence of crucial FNDMC simulation parameters, namely the one-electron models, basis sets, and pseudopotentials used for the generation of the trial wave function. These are shown to have a significant impact on the calculated FNDMC interaction energies and good agreement between CCSD(T) and FNDMC is found when nodal hypersurfaces of sufficient quality are used. Based on our proposed consensus reference value, we go on to benchmark the standard toolbox of lower-level quantum chemistry methods for this model interaction. Newly-developed dispersion-corrected DFT methods perform reasonably well despite the partial charge transfer character of the interaction and might well be worthy of further study in larger lithium-thiophene systems.

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Section: Methodological Aspectsmentioning

confidence: 99%

The Lithium–Thiophene Riddle Revisited

Korth¹,

Towler²

2011

J. Phys. Chem. A

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“…Improved computational accuracy can be achieved with the continuum quantum Monte Carlo (QMC) technique 21,22 MP grid was chosen for both the B3 and B1 structures. The DFT calculations were performed using the Quantum ESPRESSO code 43 .…”

Section: Theorymentioning

confidence: 99%

“…The QMC (VMC and DMC) calculations were performed using the CASINO code 21,22 . We used trial wave functions of Slater-Jastrow types.…”

Section: Qmc Calculationsmentioning

confidence: 99%

“…In this work we study the B3-B1 pressure induced phase transition in GaAs using the highly accurate continuum Quantum Monte Carlo (QMC) method 21,22 . We investigate whether the choice of charge density functionals as implemented in standard density functional theory (DFT) used so far to study this phase transition significantly affects the obtained phase transition pressure, and also assess the accuracy of QMC in predicting the B3-B1 pressure induced phase transition in…”

Section: Introductionmentioning

confidence: 99%

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Quantum Monte Carlo study of pressure-inducedB3−B1phase transition in GaAs

Ouma¹,

Mapelu

Makau

et al. 2012

Phys. Rev. B

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We have investigated the transition pressure, p t , of bulk GaAs from the zinc blende (B3) to the rocksalt (B1) structure using the local density approximation (LDA), generalized gradient approximation (PBE-GGA) and diffusion Monte Carlo (DMC). We took into account finite temperature effects (zero-point vibrational effects) as well as finite size corrections. Our DMC calculation using GGA trial nodal surface supports the higher value of the transition pressure (∼ 17 GPa) than the lower value of (∼ 12 GPa), both of which are experimentally reported values. This projection increases the transition pressure, p t , from DFT predictions, being of the same tendency as that for Si bulk crystal. The choice of the XC functional in DFT was found to significantly determine the phase transition pressure, while DMC gave more accurate results for this transition pressure.

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“…Compared to these high-level wavefunction-based methods, quantum Monte Carlo (QMC) methods [22][23][24] scale much more favorably with the system size. Having 'embarrassingly-parallel' characteristic of the Monte Carlo algorithm, the QMC approaches are highly attractive, especially given the recent trend in high-performance computing to employ a large number of processing cores for achieving a better performance (more than 3 million cores in the fastest supercomputer in 2014 [25]).…”

Section: Introductionmentioning

confidence: 99%

Reptation Quantum Monte Carlo calculation of charge transfer: The Na–Cl dimer

Yao

Kanai

2015

Chemical Physics Letters

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a b s t r a c tThe phenomenon of ion pairing in aqueous solutions is of widespread importance in chemistry and physics, and charge transfer between the ions plays a significant role. We examine the performance of quantum Monte Carlo (QMC) calculations for describing the charge transfer behavior in a NaCl dimer. The influence of the fermion nodes is investigated by obtaining the electron density using the reptation Monte Carlo approach. The fermion nodes are given by single-particle orbitals in Slater-Jastrow trial wavefunctions. We consider the single-particle orbitals from Hartree-Fock and density functional theory calculations with several exchange-correlation approximations. Appreciable dependence of the charge transfer on the fixed-node approximation was found although the total energy was found to be rather insensitive. Our work shows that a careful examination of the fixed-node approximation is necessary for quantifying charge transfer in QMC calculations even when other properties such as reaction energetics are insensitive to the approximation.

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The quantum Monte Carlo method

Cited by 23 publications

References 87 publications

The Lithium–Thiophene Riddle Revisited

The Lithium–Thiophene Riddle Revisited

Quantum Monte Carlo study of pressure-inducedB3−B1phase transition in GaAs

Reptation Quantum Monte Carlo calculation of charge transfer: The Na–Cl dimer

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