A QM/MM program using frozen localized orbitals and the Huzinaga equation

Research output: Contribution to journalArticle

5 Citations (Scopus)


A mixed QM/MM computer program coupling Amber and Mrcc is presented. This is the first implementation of the Huzinaga equation-based local self-consistent field (HLSCF) method that makes it possible to calculate ab initio wave functions without orthogonalizing the basis set to the frozen orbitals separating the QM and MM subsystems. A significant novelty of the program is that it includes an automatic generation of the frozen localized orbitals obtained from calculations performed for model molecules cut out of the system. The Amber–Mrcc code also allows the use of the link atom (LA) approach. Sample calculations were performed to check the performance of both the HLSCF and the LA approaches by describing the interactions between the QM and MM subsystems with electrostatic embedding. It was found that the conceptually appealing HLSCF method is a competitive alternative to the LA method.

Original languageEnglish
Article number132
JournalTheoretical Chemistry Accounts
Issue number11
Publication statusPublished - Nov 1 2015


  • Frozen strictly localized molecular orbital
  • Huzinaga equation-based local self-consistent field (HLSCF)
  • Link atom
  • Mixed quantum mechanics/molecular mechanics

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'A QM/MM program using frozen localized orbitals and the Huzinaga equation'. Together they form a unique fingerprint.

  • Cite this