• Cavity-Free Continuum Solvation: Implementation and Parametrization in a Multiwavelet Framework 

      Gerez Sazo, Gabriel Adolfo; Remigio Eikås, Roberto Di; Jensen, Stig Rune; Bjørgve, Magnar; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-18)
      We present a multiwavelet-based implementation of a quantum/classical polarizable continuum model. The solvent model uses a diffuse solute–solvent boundary and a position-dependent permittivity, lifting the sharp-boundary assumption underlying many existing continuum solvation models. We are able to include both surface and volume polarization effects in the quantum/classical coupling, with guaranteed ...
    • Full Breit Hamiltonian in the Multiwavelets Framework 

      Tantardini, Christian; Remigio, Roberto Di; Bjørgve, Magnar; Jensen, Stig Rune; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-01)
      New techniques in core–electron spectroscopy are necessary to resolve the structures of oxides of f-elements and other strongly correlated materials that are present only as powders and not as single crystals. Thus, accurate quantum chemical methods must be developed to calculate core spectroscopic properties in such materials. In this contribution, we present an important development in this ...
    • Kinetic energy-free Hartree–Fock equations: an integral formulation 

      Jensen, Stig Rune; Durdek, Antoine Pacifique Romain; Bjørgve, Magnar; Wind, Peter; Flå, Tor; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-18)
      We have implemented a self-consistent feld solver for Hartree–Fock calculations, by making use of Multiwavelets and Multiresolution Analysis. We show how such a solver is inherently a preconditioned steepest descent method and therefore a good starting point for rapid convergence. A distinctive feature of our implementation is the absence of any reference to the kinetic energy operator. This is ...
    • Separable representations of the Poisson, Helmholtz and complex Helmholtz kernels 

      Bjørgve, Magnar (Master thesis; Mastergradsoppgave, 2017-02-15)
      For high accuracy applications of integral operators in higher dimensions the complexity of operation and storage usually grows exponentially with dimensions. One method that has proven successful for handling these difficulties are the separation of the integral kernels as linear combinations of products of one-dimensional kernels, commonly referred to as separation of variables. In this ...
    • Unleashing the VAMPyR. A Python Journey into the Realm of Multiwavelets and Quantum Chemisty 

      Bjørgve, Magnar (Doctoral thesis; Doktorgradsavhandling, 2024-04-04)
      This thesis presents VAMPyR, an advancement in quantum chemistry that significantly mitigates the challenges inherent in high-precision computational methods. By providing a Python interface to the multiwavelet-based functionalities of MRCPP, VAMPyR enables a more intuitive, accessible, and efficient approach to quantum chemical calculations, reducing the complexity traditionally encountered with ...