Our laboratories have recently calculated a set of collision coefficients characterizing
the efficiency of energy transfer between helium and/or hydrogen and a large variety of
interstellar molecules. We have considered with molecules ranging from light hydrides,
observed by the Herschel Space Observatory, to medium size molecules, observed by mm
antennas, to heavy complex organic molecules, observed also in the cm range. We present a
review of recent theoretical results obtained in our laboratories, for various kinds of
commonly observed molecules.