ACE-Molecule: An open-source real-space quantum chemistry package

Abstract

ACE-Molecule (advanced computational engine for molecules) is a real-space quantum chemistry package for both periodic and non-periodic systems. ACE-Molecule adopts a uniform real-space numerical grid supported by the Lagrange-sinc functions. ACE-Molecule provides density functional theory (DFT) as a basic feature. ACE-Molecule is specialized in efficient hybrid DFT and wave-function theory calculations based on Kohn–Sham orbitals obtained from a strictly localized exact exchange potential. It is open-source oriented calculations with a flexible and convenient development interface. Thus, ACE-Molecule can be improved by actively adopting new features from other open-source projects and offers a useful platform for potential developers and users. In this work, we introduce overall features, including theoretical backgrounds and numerical examples implemented in ACE-Molecule.

Reducing Qubit Requirements while Maintaining Numerical Precision for the Variational Quantum Eigensolver: A Basis-Set-Free Approach

“…Basis-set-free approaches represent the spatial part of the orbitals or other wave functions without the use of a globally defined basis set. Some examples are approaches based on Daubechies wavelets, 7−9 Lagrange-sinc functions, 10 or multiresolution analysis (MRA). 11−14 MRA offers an alternative to the traditional basis sets by representing the spatial parts of molecular wave functions on adaptive real-space grids, where wavelet-based numerical techniques allow adaptive refinement of the grid in a black-box fashion.…”

“…Basis-set-free approaches represent the spatial part of the orbitals or other wave functions without the use of a globally defined basis set. Some examples are approaches based on Daubechies wavelets, − Lagrange-sinc functions, or multiresolution analysis (MRA). − MRA offers an alternative to the traditional basis sets by representing the spatial parts of molecular wave functions on adaptive real-space grids, where wavelet-based numerical techniques allow adaptive refinement of the grid in a black-box fashion. In this representation, each function (orbital) is described individually by automatically constructed adaptive multiwavelets, making it a basis-set-free representation, because the numerical basis is individually constructed from a proper L 2 basis with a numerically well-defined truncation criterion.…”

System-Specific Separable Basis Based on Tucker Decomposition: Application to Density Functional Calculations

“…In GOSPEL, the Hartree potential was evaluated using the interpolation scaling method, as in our previous studies. 23 , 24 An XC potential is evaluated from the experimental version of libXC . 25 …”

Free and Open Source Software for Computational Chemistry Education

“…ABINIT 88 is Fortran program for plane wave calculations that supports DFT as well as more advanced formalisms like many-body perturbation theory. 154 is a C++ program that employs uniform real-space grids of Lagrange sinc functions and pseudopotentials, and supports density functional calculations on both periodic and non-periodic systems and wave function theory calculations based on Kohn-Sham orbitals.…”