SUPPRESSION OF THE COLLISIONAL QUENCHING OF N2(A'(5)SIGMA(G)(-15(2) ISOTOPIC-SUBSTITUTION()) BY N)

The excitation of nitrogen molecules into the B 3PI(g) state by collis ional intramolecular energy transfer from N2(A'5SIGMA(g)+) was studied for N-15(2) and N-14(2) under single-collision conditions in a N2 be am/He target gas cell arrangement. In contrast to the N-14(2) case, th e emission from N-15(2) shows no enhancement of any particular rotatio nal/fine structure lines in the N2(B-->A) spectrum. This demonstrates that no perturbations between the A' and B states of N-15(2) exist, su ch as were recently found in the case of N-14(2). As a result, the que nching cross section of the A' state of the N-15(2) molecule must be m uch smaller than that of the N-14(2) isotope.