  While the traditional local-density approximation (LDA) cannot describe Mott
insulators, {\it ab-initio} determination of the Hubbard $U$, for example,
limits LDA-plus dynamical mean field theory (DMFT) approaches. Here, we attempt
to overcome these bottlenecks by achieving fusion of the quantum chemistry (QC)
approach with DMFT. QC+DMFT supplants the LDA bandstructure by its QC
counterpart as an input to DMFT. Using QC+DMFT, we show that undoped
$La_{2}CuO_{4}$ is a $d$-Mott insulator, and qualitatively discuss the
circulating current- and incoherent metal phase, at small but finite hole
doping. Very good quantitative agreement with experimental photoemission- and
optical spectra constitutes strong support for efficacy of QC+DMFT. Our work
thus opens a new avenue for truly {\it ab-initio} correlation-based approaches
to describe correlated electronic systems in general.
