The triplet potential energy surface for the N(S-4) + CH2F((2)A') reaction
has been studied employing both MP2 and DFT(B3LYP) methods. The energies of
the involved species have been refined using the G2, CBS, and CCSD(T) meth
ods, respectively. The general picture for this reaction is a typical addit
ion-elimination mechanism, where initially a rather stable intermediate, (N
CH2F)-N-. ., is obtained by the interaction of nitrogen with the radical th
rough the carbon atom. There are two preferred products from the thermodyna
mic viewpoint, trans-FC.=NH and HFC=N-., the latter one being slightly more
stable. Other possible products, such as H2C=N-. and trans-HC.=NH, are als
o exothermic but less stable, whereas cis-HC.=NF is even clearly endothermi
c. From the kinetic viewpoint, HFC=N-. is predicted to be the preferred pro
duct. It seems that neither isomerization nor subsequent elimination of hyd
rogen or fluorine atoms from the primary products is feasible, since all th
ese processes are much less exothermic and involve considerable kinetic bar
riers.