Accurate, Efficient, and Simple Forces Computed with Quantum Monte Carlo Methods
نویسندگان
چکیده
منابع مشابه
Accurate, efficient, and simple forces computed with quantum Monte Carlo methods.
Computation of ionic forces using quantum Monte Carlo methods has long been a challenge. We introduce a simple procedure, based on known properties of physical electronic densities, to make the variance of the Hellmann-Feynman estimator finite. We obtain very accurate geometries for the molecules H(2), LiH, CH(4), NH(3), H(2)O, and HF, with a Slater-Jastrow trial wave function. Harmonic frequen...
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The diffusion quantum Monte Carlo DMC method is the most accurate approach available for calculating the total energies of solids and large molecules.1 Energy gradients are also of great significance in quantum mechanical calculations, because they give the forces on atoms which may be used to relax structures and perform molecular dynamics simulations. Progress in such calculations using DMC m...
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Atomic force calculations within the variational and diffusion quantum Monte Carlo methods are described. The advantages of calculating diffusion quantum Monte Carlo forces with the 'pure' rather than the 'mixed' probability distribution are discussed. An accurate and practical method for calculating forces using the pure distribution is presented and tested for the SiH molecule. The statistics...
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In order to overcome the difficulty of optimizing molecular geometry using quantum Monte Carlo methods, we introduce various approximations to the exact force expectation value. We follow Pulay’s suggestion @Mol. Phys. 17, 153 ~1969!# to correct the Hellmann–Feynman estimator by introducing the contributions due to the changes in the wave function with respect to the nuclear positions. When use...
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This paper deals with the optimization of trial states for the computation of dominant eigenvalues of operators and very large matrices. In addition to preliminary results for the energy spectrum of van der Waals clusters, we review results of the application of this method to the computation of relaxation times of independent relaxation modes at the Ising critical point in two dimensions.
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 2005
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.94.036404