posted on 2018-08-28, 00:00authored byMilica Feldt, Ricardo A. Mata
In this work we discuss first applications
of the local molecular
orbital:molecular orbital (LMOMO) scheme on open-shell systems, focusing
on the advantages of isolating the orbital space of (or near) metal
centers. We have used as a benchmark ligand exchange reactions, discussing
the multireference character observed in local and canonical calculations,
the impact of the local domain approximations, and the convergence
of the hybrid scheme. After drawing some conclusions on how to build
a selection for high level regions, we applied the method to the rate-determining
steps in a nitrite reductase catalyzed reaction step. We have been
able to obtain an overall description of the proton, electron transfers
energetics occurring in the system which provide a picture for the
first time in consistence with the experimental findings. The use
of the hybrid scheme is particularly useful in the calculation of
the electronic affinities which had previously only been calculated
at lower levels of theory. These results show the potential of such
local orbital approaches to deal with specific correlation effects
confined to a metal center or their direct vicinity.