  In the present work, the analytical description of an intermolecular
vibrational energy transfer, analyzed by two dimensional infrared spectroscopy,
is established. The energy transfer process takes place between the dark
combination states of low frequency modes pertaining to different molecules.
The appearance of the cross peaks results from coherent transfer between these
combination states and an optically active state of the acceptor molecule. Such
a process has recently been observed experimentally between the nitrile groups
of acetonitrile-d3 and benzonitrile molecules. This molecular system will be
used as a model for the simulations of their two-dimensional infrared spectra.
The dependence of the cross-peak growth, which is a signature of the
intermolecular energy transfer, will be discussed in detail as a function of
the molecular dynamical constants.
