Blar i forfatter Artikler, rapporter og annet (kjemi) "Jensen, Hans Jørgen Aagaard"

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    • Exact two-component Hamiltonians for relativistic quantum chemistry: Two-electron picture-change corrections made simple 

      Knecht, Stefan; Repisky, Michal; Jensen, Hans Jørgen Aagaard; Saue, Trond (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-19)
      Based on self-consistent field (SCF) atomic mean-field (amf) quantities, we present two simple yet computationally efficient and numerically accurate matrix-algebraic approaches to correct both scalar-relativistic and spin–orbit two-electron picture-change effects (PCEs) arising within an exact two-component (X2C) Hamiltonian framework. Both approaches, dubbed amfX2C and e(xtended)amfX2C, allow us ...

    • Molecular quantum mechanical gradients within the polarizable embedding approach-Application to the internal vibrational Stark shift of acetophenone 

      List, Nanna Holmgaard; Beerepoot, Maarten T. P.; Olsen, Jógvan Magnus Haugaard; Gao, Bin; Ruud, Kenneth; Jensen, Hans Jørgen Aagaard; Kongsted, Jacob (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-21)
      We present an implementation of analytical quantum mechanical molecular gradients within the polarizable embedding (PE) model to allow for efficient geometry optimizations and vibrational analysis of molecules embedded in large, geometrically frozen environments. We consider a variational ansatz for the quantum region, covering (multiconfigurational) self-consistent-field and Kohn–Sham density ...