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Jonas Feldt1, Antoine Bienvenu1, Roland Assaraf1

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This study introduces a novel spin-dependent core definition in variational Monte Carlo (VMC) calculations. This method significantly enhances computational efficiency for molecular properties, especially for transition metals.

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Area of Science:

  • Computational chemistry
  • Quantum mechanics

Background:

  • Variational Monte Carlo (VMC) methods are crucial for calculating molecular properties.
  • Current VMC estimators can be computationally expensive and depend on all electron positions.

Purpose of the Study:

  • To develop a more efficient VMC approach using single-core subsamplings.
  • To introduce a spin-dependent core definition to improve VMC calculations.

Main Methods:

  • Utilizing numerically cheap single-core subsamplings for improved VMC estimators.
  • Defining a spin-dependent core that restricts dynamics to valence electrons.
  • Applying the method to alkane chains, silicon clusters, and cobalt clusters.

Main Results:

  • The new estimators depend only on valence electron positions, acting as an effective core potential.
  • The spin-dependent core reduces estimator variance and restricts VMC dynamics.
  • Significant efficiency gains observed, up to two orders of magnitude for transition metals like cobalt.

Conclusions:

  • The proposed spin-dependent core definition simplifies VMC algorithms and enhances computational efficiency.
  • This approach offers substantial performance improvements for molecular property calculations, particularly for heavy elements.