Chemical Physics Letters vol:344 issue:1-2 pages:213-220
The singlet ((1)A') potential energy surface (PES) of the Mg + N2O reaction has been studied at both MP2/6-311+G* and CCSD(T)/6-311+G* levels. Two kinds of reaction channels have been identified: the first one is when the Mg atom approaches N2O in a perpendicular fashion (left perpendicular Mg-O-N approximate to 90.0 degrees) and the second is when Mg approaches from the end-on (oxygen side) of N2O (left perpendicular Mg-O-N approximate to 148.0 degrees). The CCSD(T) activation barrier for the perpendicular approach is 48.8 kJ/mol and compares well with the experimentally determined value (44.3 +/-1.3 kJ/mol). The transition structure for the end-on approach has higher energy barrier, 95.7 kJ/mol. Charges analysis and electron density calculations by atoms-in-molecule theory showed that the reaction mechanism is controlled by covalent interactions between the Mg atom and the O end of N2O rather than by an electron transfer from the Mg atom to the N2O molecule. (C) 2001 Elsevier Science B.V. All rights reserved.