Steric effect in the energy transfer reaction of Ar(3P2)+N2

Steric effect for N-2(C,(3)Pi(u)) formation in the energy transfer reaction of Ar(P-3(2))+N-2 was directly measured by using an oriented Ar(P-3(2),M-J=2) beam at a collision energy of 0.06 eV. The N-2(C,(3)Pi(u)) chemiluminescence intensity was measured as a function of the magnetic orientation field direction in the collision frame. A significant alignment effect on the energy transfer probability was observed. The relative reactivity for each magnetic substate in the collision frame sigma(parallel to M)(')(J)parallel to was determined to be sigma(parallel to 2 parallel to):sigma(parallel to 1 parallel to):sigma(0)=0.50:0.60:1.00. It is suggested that the observed steric effect is primarily due to the favorable configuration of the 3p orbital for the efficient overlap with the 2 sigma(u) molecular orbital of N-2. (c) 2006 American Institute of Physics.