Collision-induced electronic transitions from the N-2 a(1)Pi(g)(v=1 and 2) levels

We have used a double-resonance-enhanced multiphoton ionization (REMPI) technique to determine the quenching rates for collision-induced electronic transitions (CIETs) from the N-2 a(1) Pi(g)(upsilon = 1) level as a function of the collision partners He, Ar, and nitrogen. The branching ratio from this level to the a'(1) Sigma(u)(-)(upsilon = 2 and 1) levels is determined experimentally and found to be in excellent agreement with an empirical model developed previously. This ratio is used to determine state-specific CIET rates from pressure-dependent radiative decay curves using a double-exponential model for collisional deactivation. The rates are determined for each of the collision partners, and the most efficient quenchant is determined to be nitrogen followed by Ar and He. In addition, the propensities for CIET have been observed from the a(1) Pi(g)(upsilon = 2) level to the a'(1) Sigma(u)(-)(upsilon = 3) level as a function of the rare-gas partners. There is a dependence of the propensities on the collision partner, and helium has a smaller Delta J propensity than Ar.