Abstract:

 Ab initio UHF/6-31G** method have been used to study the reaction mechanism of CH3O with NO on the singlet and triplet potential energy surfaces. Two parallel reaction channels, leading to products CH3ONO(a) and HCHO+HNO(b), were separately found on these potential energy surfaces. The Intrinsic Reaction Coordinates (IRC) for the above reactions were traced by using the algorithm of Morokuma. The activation barriers at 6-31G**+ZPE level are 86.86 kJ•mol-1 and 159.22 kJ•mol-1 respectively for path(a) and path(b) on the singlet-state surface, and 139.20 kJ•mol-1 and 196.49 kJ•mol-1 respectively on the triplet-state surface. The theoretical results show that the reaction occurs more favorably on the singlet-state surface and that CH3ONO is predominately produced than other products, which is in agreement with the experimental result.

Key words: CH₃O, NO, Reaction mechanism, AB inito