The pi-coordinated interaction of a palladium atom with acetylene and
ethylene is investigated through theoretical calculations, including e
lectron correlation effects. The interaction is analysed as a van der
Waals one and it is concluded that the ground state of PdC2H2 and PdC2
H4 molecules are bound by 48-93 kJ mol-1 and 85.85 kJ mol-1 relative t
o the ground state of the Pd (1S) atom, C2H2 (1SIGMA(g)) and C2H4 (1A(
g)) molecules. A comparison with experimental results for this system
is presented.