  The effects of long-range intermolecular interactions on characteristic
features of soliton bound states, consisting of localized excitons and
polaritons in molecular crystals interacting with a high-intensity optical
field, are investigated. Analytical solutions to the resulting modified
nonlinear Schr\"odinger equation are obtained in terms of elliptic-type bright-
and dark-soliton structures, which are assumed to correspond to periodic trains
of pulse solitons and kink solitons respectively. Long-range intermolecular
interactions are shown to renormalize the exciton-polariton interaction
strength, hence generating a significantly huge increase in amplitudes of the
bright solitons but a decrease in amplitudes of dark solitons. Results suggest
that long-range intermolecular interactions hold relevant roles, both
qualitatively and quantitatively, in the formation of amplitude and phase
modulated strongly nonlinear exciton-polariton solitary-wave patterns, as well
as in the energy transfer along molecular crystals interacting with
high-intensity optical fields.
