We present a state interaction spin-orbit coupling method to calculate
electron paramagnetic resonance (EPR) g-tensors from density matrix
renormalization group wavefunctions. We apply the technique to compute
g-tensors for the \ce{TiF3} and \ce{CuCl4^2-} complexes, a [2Fe-2S] model of
the active center of ferredoxins, and a \ce{Mn4CaO5} model of the S2 state of
the oxygen evolving complex. These calculations raise the prospects of
determining g-tensors in multireference calculations with a large number of
open shells.Comment: 19 page
