COORDINATION OF NO2 TO ALKALINE-EARTH METALS - A THEORETICAL-STUDY

The structure and harmonic vibrational frequencies have been determine d for the alkaline-earth metal MNO2 systems (M = Be, Mg, Ca, and Sr) u sing the B3LYP method. Binding energies have also been calculated usin g conventional ab initio methods, CCSD(T), and MCPF, with different ba sis sets. Four different coordination modes of NO2 to the metal have b een considered. The C-2 upsilon eta(2)-O,O coordination mode is the mo st stable one for all metals. However, for BeNO2 the ground state is a B-2(1) state while for the other metals the (2)A(1) state is the most stable one. Our best estimates for the D-0 binding energies are 77 kc al mol(-1) for BeNO2, 53 kcal mol(-1) for MgNO2, 69 kcal mol(-1) for C aNO2, and 71 kcal mol(-1) for SrNO2.