The photodissociation dynamics of NCO have been examined using fast beam ph
otofragment translational spectroscopy. Excitation of the 1(0)(2), 3(0)(1),
and 1(0)(2)3(0)(2) transitions of the (B) over tilde (2)Pi<--<(X)over tild
e> (2)Pi band produces N(S-4) + CO photofragments exclusively, while excita
tion of the 1(0)(3)3(0)(3) transition yields primarily N(D-2) + CO photopro
ducts. The translational energy [P(E-T)] distributions yield D-0(N-CO) = 2.
34 +/-0.03 eV, and DeltaH(f,0)(0)(NCO) = 1.36 +/-0.03 eV. The P(E-T) distri
butions exhibit vibrationally resolved structure reflecting the vibrational
and rotational distributions of the CO product. The N(D-2) + CO distributi
on can be fit by phase space theory (PST), while the higher degree of CO ro
tational excitation for N(S-4) + CO products implies that NCO passes throug
h a bent geometry upon dissociation. The P(E-T) distributions suggest that
when the (B) over tilde (2)Pi<--<(X)over tilde> (2)Pi band is excited, NCO
undergoes internal conversion to its ground electronic state prior to disso
ciation. Excitation of NCO at 193 nm clearly leads to the production of N(D
-2) + CO fragments. While conclusive evidence for the higher energy O(P-3)
+ CN(X (2)Sigma (+)) channel was not observed, the presence of this dissoci
ation pathway could not be excluded. (C) 2001 American Institute of Physics
.