Relativistic Internally Contracted Multireference Electron Correlation Methods

Toru Shiozaki, Wataru Mizukami

    Research output: Contribution to journalArticlepeer-review

    34 Citations (Scopus)


    We report internally contracted relativistic multireference configuration interaction (ic-MRCI), complete active space second-order perturbation (CASPT2), and strongly contracted n-electron valence state perturbation theory (NEVPT2) on the basis of the four-component Dirac Hamiltonian, enabling accurate simulations of relativistic, quasi-degenerate electronic structure of molecules containing transition-metal and heavy elements. Our derivation and implementation of ic-MRCI and CASPT2 are based on an automatic code generator that translates second-quantized ansätze to tensor-based equations, and to efficient computer code. NEVPT2 is derived and implemented manually. The rovibrational transition energies and absorption spectra of HI and TlH are presented to demonstrate the accuracy of these methods.

    Original languageEnglish
    Pages (from-to)4733-4739
    Number of pages7
    JournalJournal of Chemical Theory and Computation
    Issue number10
    Publication statusPublished - Sept 14 2015

    All Science Journal Classification (ASJC) codes

    • Computer Science Applications
    • Physical and Theoretical Chemistry


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