Hot-atom chemiluminescence: a beam study of the N*(2D) + CH4 system

Fast N(2D) atoms colliding with CH4 at 10–200 eVCM yield CH(A,B), NH(A) and H(n⩾4) emission. From 10 to 50 eVCM the CH yield decreases, exceeding greatly that for N(4S) and N+(3P) + CH4 collisions. This indicates N(2D) insertion. Above 50 eVCM the CH yield increases again, approaching the values found with N(4S) and N+(3P). Here the CH formation is chemically unspecific (‘shattering’). The NH(A) yield decreases monotonically for all three projectiles. N(2D) insertion is here unimportant, in contrast to NH(X) from N(2D) + CH4. At ECM>50 eVCM, all projectiles give NH(A) according to the ‘billiard ball’ model.