  The main motivation for this work is the exploration of
rotational-vibrational states corresponding to electronic excitations in a
pre-Born-Oppenheimer quantum theory of molecules. These states are often
embedded in the continuum of the lower-lying dissociation channel of the same
symmetry, and thus are thought to be resonances. In order to calculate
rovibronic resonances, the pre-Born-Oppenheimer variational approach of [J.
Chem. Phys. 137, 024104 (2012)], based on the usage of explicitly correlated
Gaussian functions and the global vector representation, is extended with the
complex coordinate rotation method. The developed computer program is used to
calculate resonance energies and widths for the three-particle positronium
anion, Ps$^-$, and the four-particle positronium molecule, Ps$_2$. Furthermore,
the excited bound and resonance rovibronic states of the four-particle H$_2$
molecule are also considered. Resonance energies and widths are estimated for
the lowest-energy resonances of H$_2$ beyond the $b\ ^3\Sigma_\mathrm{u}^+$
continuum.
