Molecular physics and chemistry applications of quantum Monte Carlo

Reynolds, Peter J.; Barnett, R. N.; Hammond, B. L.; Lester, William A.

doi:10.1007/bf02628327

Cited by 60 publications

(48 citation statements)

References 34 publications

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“…Although the fixed-node error is typically a very small percentage of the total energy (0.02% for CH 2 [11]), when the total energy is large, the fixed-node error can be a significant fraction of the bond energy. This was found for N2 [12]. Thus the placement of the inner nodes can dominate the accuracy of the calculation.…”

mentioning

confidence: 70%

Valence quantum Monte Carlo with a b i n i t i o effective core potentials

Hammond¹,

Reynolds²,

Lester³

1987

The Journal of Chemical Physics

143

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Effective-core potentials (ECP’s) obtained from ab initio methods are implemented in molecular quantum Monte Carlo (QMC). The theory is presented, and applied to the calculation of electron affinities (EA) of Li and Na, the ionization potential (IP) of Mg, the binding energies (De) of NaH and Na2, and the potential energy curve of Na2. In all cases ECP–QMC results are found to be as accurate as previous all-electron results. In particular, the calculated quantities (vs experimental values) are (in eV): EA(Li)=0.611±0.020 (0.620), EA(Na)=0.555±0.021 (0.546), IP(Mg)=7.637±0.026 (7.646), De (NaH) =1.954±0.073 (1.971), and De (Na2)=0.746±0.020 (0.747). In addition, the statistical precision obtained surpasses that which can be readily achieved in all-electron QMC calculations on these systems.

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mentioning

confidence: 70%

Valence quantum Monte Carlo with a b i n i t i o effective core potentials

Hammond¹,

Reynolds²,

Lester³

1987

The Journal of Chemical Physics

143

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“…20,21,22 Essentially, with this method the possible bias introduced by ψ T in the mixed estimator Φ 0 |Ô|ψ T are removed by proper weighting of the configurations generated along the simulation.…”

Section: Molecular Interaction and Methodsmentioning

confidence: 99%

“…Quantities like the kinetic energy per particle and Lindemann's ratio have been computed within the pure estimator approach 20,21,22 in order to remove any possible bias coming out from the trial wave function used for importance sampling. In this way, we quote quantum isotopic effects in hydrogen directly and only within the statistical uncertainty.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional molecularpara-hydrogen andortho-deuterium at zero temperature

Cazorla

Boronat

2008

Phys. Rev. B

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We study molecular para-hydrogen (p-H2) and ortho-deuterium (o-D2) in two dimensions and in the limit of zero temperature by means of the diffusion Monte Carlo method. We report energetic and structural properties of both systems like the total and kinetic energy per particle, radial pair distribution function, and Lindemann's ratio in the low pressure regime. By comparing the total energy per particle as a function of the density in liquid and solid p-H2 , we show that molecular para-hydrogen, and also ortho-deuterium, remain solid at zero temperature. Interestingly, we assess the quality of three different symmetrized trial wave functions, based on the Nosanow-Jastrow model, in the p-H2 solid film at the variational level. In particular, we analyze a new type of symmetrized trial wave function which has been used very recently to describe solid 4 He and found that also characterizes hydrogen satisfactorily. With this wave function, we show that the one-body density matrix ̺1(r) of solid p-H2 possesses off-diagonal long range order, with a condensate fraction that increases sizably in the negative pressure regime.

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“…This bias is less than that encountered by VMC, but still present. This can be alleviated somewhat by the use of "extrapolated estimators", and by the "forward-walking" method [27].…”

Section: Diffusion Monte Carlomentioning

confidence: 99%

First Principles Methods: A Perspective from Quantum Monte Carlo

Morales

Clay

Pierleoni

et al. 2013

Entropy

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Quantum Monte Carlo methods are among the most accurate algorithms for predicting properties of general quantum systems. We briefly introduce ground state, path integral at finite temperature and coupled electron-ion Monte Carlo methods, their merits and limitations. We then discuss recent calculations using these methods for dense liquid hydrogen as it undergoes a molecular/atomic (metal/insulator) transition. We then discuss a procedure that can be used to assess electronic density functionals, which in turn can be used on a larger scale for first principles calculations and apply this technique to dense hydrogen and liquid water.

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Molecular physics and chemistry applications of quantum Monte Carlo

Cited by 60 publications

References 34 publications

Valence quantum Monte Carlo with a b i n i t i o effective core potentials

Valence quantum Monte Carlo with a b i n i t i o effective core potentials

Two-dimensional molecularpara-hydrogen andortho-deuterium at zero temperature

First Principles Methods: A Perspective from Quantum Monte Carlo

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